// Copyright 2023 Greptime Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::fmt::Debug;
use std::net::SocketAddr;
use std::path::Path;
use std::sync::Arc;
use std::{fs, path};

use async_trait::async_trait;
use cache::{build_fundamental_cache_registry, with_default_composite_cache_registry};
use catalog::CatalogManagerRef;
use catalog::information_schema::InformationExtensionRef;
use catalog::kvbackend::{CatalogManagerConfiguratorRef, KvBackendCatalogManagerBuilder};
use catalog::process_manager::ProcessManager;
use clap::Parser;
use common_base::Plugins;
use common_catalog::consts::{MIN_USER_FLOW_ID, MIN_USER_TABLE_ID};
use common_config::{Configurable, metadata_store_dir};
use common_datasource::object_store::{LocalFileAccess, configured_local_path};
use common_error::ext::BoxedError;
use common_meta::DatanodeId;
use common_meta::cache::{LayeredCacheRegistryBuilder, LayeredCacheRegistryRef};
use common_meta::ddl::flow_meta::FlowMetadataAllocator;
use common_meta::ddl::table_meta::TableMetadataAllocator;
use common_meta::ddl::{DdlContext, NoopRegionFailureDetectorControl};
use common_meta::ddl_manager::{DdlManager, DdlManagerConfiguratorRef, DdlManagerRef};
use common_meta::key::flow::FlowMetadataManager;
use common_meta::key::{TableMetadataManager, TableMetadataManagerRef};
use common_meta::kv_backend::KvBackendRef;
use common_meta::node_manager::{FlownodeRef, NodeManagerRef};
use common_meta::procedure_executor::{LocalProcedureExecutor, ProcedureExecutorRef};
use common_meta::region_keeper::MemoryRegionKeeper;
use common_meta::region_registry::LeaderRegionRegistry;
use common_meta::sequence::{Sequence, SequenceBuilder};
use common_meta::wal_provider::{WalProviderRef, build_wal_provider};
use common_options::plugin_options::StandaloneFlag;
use common_procedure::ProcedureManagerRef;
use common_query::prelude::set_default_prefix;
use common_telemetry::info;
use common_telemetry::logging::{DEFAULT_LOGGING_DIR, TracingOptions};
use common_time::timezone::set_default_timezone;
use common_version::{short_version, verbose_version};
use datanode::config::{DatanodeOptions, StorageConfig};
use datanode::datanode::{Datanode, DatanodeBuilder};
use datanode::region_server::RegionServer;
use flow::{
    FlowDualEngineRef, FlownodeBuilder, FlownodeInstance, FlownodeOptions, FrontendClient,
    FrontendInvoker, GrpcQueryHandlerWithBoxedError,
};
use frontend::frontend::Frontend;
use frontend::instance::StandaloneDatanodeManager;
use frontend::instance::builder::FrontendBuilder;
use frontend::server::Services;
use meta_srv::metasrv::{FLOW_ID_SEQ, TABLE_ID_SEQ};
use plugins::PluginOptions;
use plugins::frontend::context::{
    CatalogManagerConfigureContext, StandaloneCatalogManagerConfigureContext,
};
use plugins::standalone::context::DdlManagerConfigureContext;
use servers::tls::{TlsMode, TlsOption, merge_tls_option};
use snafu::{OptionExt, ResultExt};
use standalone::options::StandaloneOptions;
use standalone::{StandaloneInformationExtension, StandaloneRepartitionProcedureFactory};
use tracing_appender::non_blocking::WorkerGuard;

use crate::error::{OtherSnafu, Result, StartFlownodeSnafu};
use crate::options::{GlobalOptions, GreptimeOptions};
use crate::{App, create_resource_limit_metrics, error, log_versions, maybe_activate_heap_profile};

pub const APP_NAME: &str = "greptime-standalone";

fn standalone_local_file_access(
    storage: &StorageConfig,
) -> common_datasource::error::Result<LocalFileAccess> {
    let data_home = configured_local_path(&storage.data_home)?;
    let copy_root = match &storage.copy_root {
        Some(root) => configured_local_path(root)?.with_context(|| {
            common_datasource::error::InvalidLocalFileRootConfigSnafu {
                root: root.clone(),
                reason: "copy_root must be a local path or file URL".to_string(),
            }
        })?,
        None => {
            let Some(data_home) = &data_home else {
                info!(
                    "SQL access to local files is disabled because storage.data_home is not a local path and storage.copy_root is unset"
                );
                return Ok(LocalFileAccess::Disabled);
            };
            data_home.join("copy")
        }
    };

    let access = LocalFileAccess::sandboxed(&copy_root)?;
    if let Some(data_home) = data_home {
        let canonical_data_home = data_home.canonicalize().with_context(|_| {
            common_datasource::error::InvalidLocalFileRootSnafu {
                root: data_home.display().to_string(),
            }
        })?;
        let canonical_copy_root = access.sandbox_root().with_context(|| {
            common_datasource::error::InvalidLocalFileRootConfigSnafu {
                root: copy_root.display().to_string(),
                reason: "sandboxed local file access has no root".to_string(),
            }
        })?;
        let default_copy_root = canonical_data_home.join("copy");
        let exposes_internal_files = canonical_data_home.starts_with(canonical_copy_root)
            || (canonical_copy_root.starts_with(&canonical_data_home)
                && !canonical_copy_root.starts_with(default_copy_root));
        if exposes_internal_files {
            return common_datasource::error::InvalidLocalFileRootConfigSnafu {
                root: copy_root.display().to_string(),
                reason: "copy_root must not expose files in data_home outside data_home/copy"
                    .to_string(),
            }
            .fail();
        }
    }

    Ok(access)
}

#[derive(Parser)]
pub struct Command {
    #[clap(subcommand)]
    subcmd: SubCommand,
}

impl Command {
    pub async fn build(&self, opts: GreptimeOptions<StandaloneOptions>) -> Result<Instance> {
        self.subcmd.build(opts).await
    }

    pub fn load_options(
        &self,
        global_options: &GlobalOptions,
    ) -> Result<GreptimeOptions<StandaloneOptions>> {
        self.subcmd.load_options(global_options)
    }
}

#[derive(Parser)]
enum SubCommand {
    Start(StartCommand),
}

impl SubCommand {
    async fn build(&self, opts: GreptimeOptions<StandaloneOptions>) -> Result<Instance> {
        match self {
            SubCommand::Start(cmd) => cmd.build(opts).await,
        }
    }

    fn load_options(
        &self,
        global_options: &GlobalOptions,
    ) -> Result<GreptimeOptions<StandaloneOptions>> {
        match self {
            SubCommand::Start(cmd) => cmd.load_options(global_options),
        }
    }
}

pub struct Instance {
    datanode: Datanode,
    frontend: Frontend,
    flownode: FlownodeInstance,
    procedure_manager: ProcedureManagerRef,
    leader_services_controller: Box<dyn StandaloneLeaderServicesController>,
    leader_services_context: LeaderServicesContext,
    // Keep the logging guard to prevent the worker from being dropped.
    _guard: Vec<WorkerGuard>,
}

impl Instance {
    /// Find the socket addr of a server by its `name`.
    pub fn server_addr(&self, name: &str) -> Option<SocketAddr> {
        self.frontend.server_handlers().addr(name)
    }

    /// Get the mutable Frontend component of this Standalone instance for externally modification
    /// by others (might not be in this code base, so don't delete this function).
    pub fn mut_frontend(&mut self) -> &mut Frontend {
        &mut self.frontend
    }

    /// Get the Datanode component of this Standalone instance for externally usage
    /// by others (might not be in this code base, so don't delete this function).
    pub fn datanode(&self) -> &Datanode {
        &self.datanode
    }
}

#[async_trait]
impl App for Instance {
    fn name(&self) -> &str {
        APP_NAME
    }

    async fn start(&mut self) -> Result<()> {
        self.datanode.start_telemetry();

        self.leader_services_controller
            .start(self.leader_services_context.clone())
            .await?;

        plugins::start_frontend_plugins(&self.frontend.instance)
            .await
            .context(error::StartFrontendSnafu)?;

        self.frontend
            .start()
            .await
            .context(error::StartFrontendSnafu)?;

        self.flownode.start().await.context(StartFlownodeSnafu)?;

        Ok(())
    }

    async fn stop(&mut self) -> Result<()> {
        self.frontend
            .shutdown()
            .await
            .context(error::ShutdownFrontendSnafu)?;

        self.leader_services_controller
            .stop(
                self.procedure_manager.clone(),
                self.datanode.region_server(),
            )
            .await?;

        self.datanode
            .shutdown()
            .await
            .context(error::ShutdownDatanodeSnafu)?;

        self.flownode
            .shutdown()
            .await
            .context(error::ShutdownFlownodeSnafu)?;

        info!("Datanode instance stopped.");

        Ok(())
    }
}

#[derive(Debug, Default, Parser)]
pub struct StartCommand {
    #[clap(long)]
    http_addr: Option<String>,
    #[clap(long = "grpc-bind-addr", alias = "rpc-bind-addr", alias = "rpc-addr")]
    grpc_bind_addr: Option<String>,
    #[clap(long)]
    mysql_addr: Option<String>,
    #[clap(long)]
    postgres_addr: Option<String>,
    #[clap(short, long)]
    influxdb_enable: bool,
    #[clap(short, long)]
    pub config_file: Option<String>,
    #[clap(long)]
    tls_mode: Option<TlsMode>,
    #[clap(long)]
    tls_cert_path: Option<String>,
    #[clap(long)]
    tls_key_path: Option<String>,
    #[clap(long)]
    tls_watch: bool,
    #[clap(long)]
    user_provider: Option<String>,
    #[clap(long, default_value = "GREPTIMEDB_STANDALONE")]
    pub env_prefix: String,
    /// The working home directory of this standalone instance.
    #[clap(long)]
    data_home: Option<String>,
}

impl StartCommand {
    /// Load the GreptimeDB options from various sources (command line, config file or env).
    pub fn load_options(
        &self,
        global_options: &GlobalOptions,
    ) -> Result<GreptimeOptions<StandaloneOptions>> {
        let mut opts = GreptimeOptions::<StandaloneOptions>::load_layered_options(
            self.config_file.as_deref(),
            self.env_prefix.as_ref(),
        )
        .context(error::LoadLayeredConfigSnafu)?;

        self.merge_with_cli_options(global_options, &mut opts.component)?;
        opts.component.sanitize();

        Ok(opts)
    }

    // The precedence order is: cli > config file > environment variables > default values.
    pub fn merge_with_cli_options(
        &self,
        global_options: &GlobalOptions,
        opts: &mut StandaloneOptions,
    ) -> Result<()> {
        if let Some(dir) = &global_options.log_dir {
            opts.logging.dir.clone_from(dir);
        }

        if global_options.log_level.is_some() {
            opts.logging.level.clone_from(&global_options.log_level);
        }

        opts.tracing = TracingOptions {
            #[cfg(feature = "tokio-console")]
            tokio_console_addr: global_options.tokio_console_addr.clone(),
        };

        let tls_opts = TlsOption::new(
            self.tls_mode,
            self.tls_cert_path.clone(),
            self.tls_key_path.clone(),
            self.tls_watch,
        );

        if let Some(addr) = &self.http_addr {
            opts.http.addr.clone_from(addr);
        }

        if let Some(data_home) = &self.data_home {
            opts.storage.data_home.clone_from(data_home);
        }

        // If the logging dir is not set, use the default logs dir in the data home.
        if opts.logging.dir.is_empty() {
            opts.logging.dir = Path::new(&opts.storage.data_home)
                .join(DEFAULT_LOGGING_DIR)
                .to_string_lossy()
                .to_string();
        }

        if let Some(addr) = &self.grpc_bind_addr {
            // frontend grpc addr conflict with datanode default grpc addr
            let datanode_grpc_addr = DatanodeOptions::default().grpc.bind_addr;
            if addr.eq(&datanode_grpc_addr) {
                return error::IllegalConfigSnafu {
                    msg: format!(
                        "gRPC listen address conflicts with datanode reserved gRPC addr: {datanode_grpc_addr}",
                    ),
                }.fail();
            }
            opts.grpc.bind_addr.clone_from(addr);
            opts.grpc.tls = merge_tls_option(&opts.grpc.tls, tls_opts.clone());
        }

        if let Some(addr) = &self.mysql_addr {
            opts.mysql.enable = true;
            opts.mysql.addr.clone_from(addr);
            opts.mysql.tls = merge_tls_option(&opts.mysql.tls, tls_opts.clone());
        }

        if let Some(addr) = &self.postgres_addr {
            opts.postgres.enable = true;
            opts.postgres.addr.clone_from(addr);
            opts.postgres.tls = merge_tls_option(&opts.postgres.tls, tls_opts.clone());
        }

        if self.influxdb_enable {
            opts.influxdb.enable = self.influxdb_enable;
        }

        if let Some(user_provider) = &self.user_provider {
            opts.user_provider = Some(user_provider.clone());
        }

        Ok(())
    }

    #[allow(unreachable_code)]
    #[allow(unused_variables)]
    #[allow(clippy::diverging_sub_expression)]
    /// Build GreptimeDB instance with the loaded options.
    pub async fn build(&self, opts: GreptimeOptions<StandaloneOptions>) -> Result<Instance> {
        common_runtime::init_global_runtimes(&opts.runtime);

        let guard = common_telemetry::init_global_logging(
            APP_NAME,
            &opts.component.logging,
            &opts.component.tracing,
            None,
            Some(&opts.component.slow_query),
        );

        crate::options::flush_dropped_plugin_warnings();
        log_versions(verbose_version(), short_version(), APP_NAME);
        maybe_activate_heap_profile(&opts.component.memory);
        create_resource_limit_metrics(APP_NAME);

        info!("Standalone start command: {:#?}", self);
        info!("Standalone options: {opts:#?}");

        let (mut instance, _) =
            Self::build_with(opts.component, opts.plugins, InstanceCreator::default()).await?;
        instance._guard.extend(guard);
        Ok(instance)
    }

    pub async fn build_with(
        mut opts: StandaloneOptions,
        plugin_opts: Vec<PluginOptions>,
        creator: InstanceCreator,
    ) -> Result<(Instance, InstanceCreatorResult)> {
        let mut plugins = Plugins::new();
        plugins.insert(StandaloneFlag);
        set_default_prefix(opts.default_column_prefix.as_deref())
            .map_err(BoxedError::new)
            .context(error::BuildCliSnafu)?;

        opts.grpc.detect_server_addr();
        let fe_opts = opts.frontend_options();
        let dn_opts = opts.datanode_options();
        let node_id = dn_opts.node_id;
        let init_regions_parallelism = dn_opts.init_regions_parallelism;

        plugins::setup_frontend_plugins_pre_build(&mut plugins, &plugin_opts, &fe_opts, None)
            .await
            .context(error::StartFrontendSnafu)?;

        plugins::setup_datanode_plugins_pre_build(&mut plugins, &plugin_opts, &dn_opts)
            .await
            .context(error::StartDatanodeSnafu)?;

        set_default_timezone(fe_opts.default_timezone.as_deref())
            .context(error::InitTimezoneSnafu)?;

        let data_home = &dn_opts.storage.data_home;
        // Ensure the data_home directory exists.
        fs::create_dir_all(path::Path::new(data_home))
            .context(error::CreateDirSnafu { dir: data_home })?;
        let local_file_access = standalone_local_file_access(&dn_opts.storage)
            .map_err(BoxedError::new)
            .context(OtherSnafu)?;

        let metadata_dir = metadata_store_dir(data_home);
        let kv_backend = creator
            .metadata_kv_backend_creator
            .create(metadata_dir, &opts)
            .await?;
        let (procedure_manager, event_recorder_handle) =
            standalone::build_procedure_manager(kv_backend.clone(), opts.procedure);

        plugins::setup_standalone_plugins(&mut plugins, &plugin_opts, &opts, kv_backend.clone())
            .await
            .context(error::SetupStandalonePluginsSnafu)?;

        // Builds cache registry
        let layered_cache_builder = LayeredCacheRegistryBuilder::default();
        let fundamental_cache_registry = build_fundamental_cache_registry(kv_backend.clone());
        let mut layered_cache_builder = with_default_composite_cache_registry(
            layered_cache_builder.add_cache_registry(fundamental_cache_registry),
        )
        .context(error::BuildCacheRegistrySnafu)?;

        if let Some(plugin_cache_builder) = plugins::standalone::configure_cache_registry(&plugins)
        {
            layered_cache_builder =
                layered_cache_builder.add_cache_registry(plugin_cache_builder.build());
        }

        let layered_cache_registry = Arc::new(layered_cache_builder.build());

        let mut builder = DatanodeBuilder::new(dn_opts, plugins.clone(), kv_backend.clone());
        builder.with_cache_registry(layered_cache_registry.clone());
        builder.with_local_file_access(local_file_access.clone());
        if let Some(writable) = creator.open_regions_writable_override {
            builder.with_open_regions_writable_override(writable);
        }

        plugins::setup_datanode_plugins_post_build(&mut plugins, &plugin_opts, &builder)
            .await
            .context(error::StartDatanodeSnafu)?;
        builder.set_plugins(plugins.clone());

        let datanode = builder.build().await.context(error::StartDatanodeSnafu)?;

        let information_extension = Arc::new(StandaloneInformationExtension::new(
            datanode.region_server(),
            procedure_manager.clone(),
        ));

        plugins.insert::<InformationExtensionRef>(information_extension.clone());

        let process_manager = Arc::new(ProcessManager::new(opts.grpc.server_addr.clone(), None));

        // for standalone not use grpc, but get a handler to frontend grpc client without
        // actually make a connection
        let (frontend_client, frontend_instance_handler) =
            FrontendClient::from_empty_grpc_handler(opts.query.clone());
        let frontend_client = Arc::new(frontend_client);

        let builder = KvBackendCatalogManagerBuilder::new(
            information_extension.clone(),
            kv_backend.clone(),
            layered_cache_registry.clone(),
        )
        .with_procedure_manager(procedure_manager.clone())
        .with_process_manager(process_manager.clone());
        let builder = if let Some(configurator) =
            plugins.get::<CatalogManagerConfiguratorRef<CatalogManagerConfigureContext>>()
        {
            let ctx = StandaloneCatalogManagerConfigureContext {
                fe_client: frontend_client.clone(),
            };
            let ctx = CatalogManagerConfigureContext::Standalone(ctx);
            configurator
                .configure(builder, ctx)
                .await
                .context(OtherSnafu)?
        } else {
            builder
        };
        let catalog_manager = builder.build();

        let table_metadata_manager =
            Self::create_table_metadata_manager(kv_backend.clone()).await?;

        let flow_metadata_manager = Arc::new(FlowMetadataManager::new(kv_backend.clone()));
        let flownode_options = FlownodeOptions {
            flow: opts.flow.clone(),
            ..Default::default()
        };

        let mut flow_builder = FlownodeBuilder::new(
            flownode_options,
            plugins.clone(),
            table_metadata_manager.clone(),
            catalog_manager.clone(),
            flow_metadata_manager.clone(),
            frontend_client.clone(),
        );

        plugins::setup_flownode_plugins_post_build(&mut plugins, &plugin_opts, &flow_builder)
            .await
            .context(error::StartFlownodeSnafu)?;
        flow_builder.set_plugins(plugins.clone());

        let flownode = flow_builder
            .build()
            .await
            .map_err(BoxedError::new)
            .context(error::OtherSnafu)?;
        let flow_engine = flownode.flow_engine();

        // set the ref to query for the local flow state
        {
            information_extension
                .set_flow_engine(flow_engine.clone())
                .await;
        }

        let node_manager = creator
            .node_manager_creator
            .create(&kv_backend, datanode.region_server(), flow_engine.clone())
            .await?;

        let table_id_allocator = creator.table_id_allocator_creator.create(&kv_backend);
        let flow_id_sequence = Arc::new(
            SequenceBuilder::new(FLOW_ID_SEQ, kv_backend.clone())
                .initial(MIN_USER_FLOW_ID as u64)
                .step(10)
                .build(),
        );
        let kafka_options = opts
            .wal
            .clone()
            .try_into()
            .context(error::InvalidWalProviderSnafu)?;
        let wal_provider = build_wal_provider(&kafka_options, kv_backend.clone())
            .await
            .context(error::BuildWalProviderSnafu)?;
        let wal_provider = Arc::new(wal_provider);
        let table_metadata_allocator = Arc::new(TableMetadataAllocator::new(
            table_id_allocator.clone(),
            wal_provider.clone(),
        ));
        let flow_metadata_allocator = Arc::new(FlowMetadataAllocator::with_noop_peer_allocator(
            flow_id_sequence,
        ));

        let ddl_context = DdlContext {
            node_manager: node_manager.clone(),
            cache_invalidator: layered_cache_registry.clone(),
            memory_region_keeper: Arc::new(MemoryRegionKeeper::default()),
            leader_region_registry: Arc::new(LeaderRegionRegistry::default()),
            table_metadata_manager: table_metadata_manager.clone(),
            table_metadata_allocator: table_metadata_allocator.clone(),
            flow_metadata_manager: flow_metadata_manager.clone(),
            flow_metadata_allocator: flow_metadata_allocator.clone(),
            region_failure_detector_controller: Arc::new(NoopRegionFailureDetectorControl),
            soft_drop_enabled: false,
            soft_drop_retention: None,
            create_database_metadata_committer: None,
        };

        let ddl_manager = DdlManager::new(
            ddl_context,
            procedure_manager.clone(),
            Arc::new(StandaloneRepartitionProcedureFactory),
        );

        let ddl_manager = if let Some(configurator) =
            plugins.get::<DdlManagerConfiguratorRef<DdlManagerConfigureContext>>()
        {
            let ctx = DdlManagerConfigureContext {
                kv_backend: kv_backend.clone(),
                fe_client: frontend_client.clone(),
                catalog_manager: catalog_manager.clone(),
            };
            configurator
                .configure(ddl_manager, ctx)
                .await
                .context(OtherSnafu)?
        } else {
            ddl_manager
        };
        ddl_manager
            .register_loaders()
            .context(error::InitDdlManagerSnafu)?;

        let procedure_executor = creator
            .procedure_executor_creator
            .create(Arc::new(ddl_manager), procedure_manager.clone())
            .await?;

        let fe_instance = FrontendBuilder::new(
            fe_opts.clone(),
            kv_backend.clone(),
            layered_cache_registry.clone(),
            catalog_manager.clone(),
            node_manager.clone(),
            procedure_executor.clone(),
            process_manager,
        )
        .with_local_file_access(local_file_access);

        plugins::setup_frontend_plugins_post_build(&mut plugins, &plugin_opts, &fe_instance)
            .await
            .context(error::StartFrontendSnafu)?;

        let fe_instance = fe_instance
            .with_plugin(plugins.clone())
            .try_build()
            .await
            .context(error::StartFrontendSnafu)?;
        let fe_instance = Arc::new(fe_instance);

        event_recorder_handle.install(fe_instance.event_recorder());

        // set the frontend client for flownode
        let grpc_handler = fe_instance.clone() as Arc<dyn GrpcQueryHandlerWithBoxedError>;
        let weak_grpc_handler = Arc::downgrade(&grpc_handler);
        frontend_instance_handler
            .set_handler(weak_grpc_handler)
            .await;

        // set the frontend invoker for flownode
        let flow_streaming_engine = flow_engine.streaming_engine();
        // flow server need to be able to use frontend to write insert requests back
        let invoker = FrontendInvoker::build_from(
            flow_streaming_engine.clone(),
            catalog_manager.clone(),
            kv_backend.clone(),
            layered_cache_registry.clone(),
            procedure_executor,
            node_manager.clone(),
            fe_instance.frontend_peer_addr().to_string(),
        )
        .await
        .context(StartFlownodeSnafu)?;
        flow_streaming_engine.set_frontend_invoker(invoker).await;

        let servers = Services::new(opts, fe_instance.clone(), plugins.clone())
            .build()
            .context(error::StartFrontendSnafu)?;

        let frontend = Frontend {
            instance: fe_instance,
            servers,
            heartbeat_task: None,
        };
        let leader_services_context = LeaderServicesContext {
            procedure_manager: procedure_manager.clone(),
            wal_provider: wal_provider.clone(),
            region_server: datanode.region_server(),
            kv_backend: kv_backend.clone(),
            cache_registry: layered_cache_registry,
            catalog_manager,
            flow_engine,
            frontend_client,
            node_id,
            init_regions_parallelism,
            plugin_options: plugin_opts,
        };

        let instance = Instance {
            datanode,
            frontend,
            flownode,
            procedure_manager,
            leader_services_controller: creator.leader_services_controller,
            leader_services_context,
            _guard: vec![],
        };
        let result = InstanceCreatorResult {
            kv_backend,
            node_manager,
            table_id_allocator,
        };
        Ok((instance, result))
    }

    pub async fn create_table_metadata_manager(
        kv_backend: KvBackendRef,
    ) -> Result<TableMetadataManagerRef> {
        let table_metadata_manager = Arc::new(TableMetadataManager::new(kv_backend));

        table_metadata_manager
            .init()
            .await
            .context(error::InitMetadataSnafu)?;

        Ok(table_metadata_manager)
    }
}

#[async_trait]
pub trait NodeManagerCreator: Send + Sync {
    async fn create(
        &self,
        kv_backend: &KvBackendRef,
        region_server: RegionServer,
        flow_server: FlownodeRef,
    ) -> Result<NodeManagerRef>;
}

pub struct DefaultNodeManagerCreator;

#[async_trait]
impl NodeManagerCreator for DefaultNodeManagerCreator {
    async fn create(
        &self,
        _: &KvBackendRef,
        region_server: RegionServer,
        flow_server: FlownodeRef,
    ) -> Result<NodeManagerRef> {
        Ok(Arc::new(StandaloneDatanodeManager {
            region_server,
            flow_server,
        }))
    }
}

/// Customizes how standalone opens its metadata KV backend.
///
/// The default implementation preserves the built-in raft-engine path. Other
/// callers can provide a custom implementation without changing standalone
/// configuration types.
#[async_trait]
pub trait MetadataKvBackendCreator: Send + Sync {
    async fn create(&self, metadata_dir: String, opts: &StandaloneOptions) -> Result<KvBackendRef>;
}

pub struct DefaultMetadataKvBackendCreator;

#[async_trait]
impl MetadataKvBackendCreator for DefaultMetadataKvBackendCreator {
    async fn create(&self, metadata_dir: String, opts: &StandaloneOptions) -> Result<KvBackendRef> {
        standalone::build_metadata_kvbackend(metadata_dir, opts.metadata_store)
            .context(error::BuildMetadataKvbackendSnafu)
    }
}

pub trait TableIdAllocatorCreator: Send + Sync {
    fn create(&self, kv_backend: &KvBackendRef) -> Arc<Sequence>;
}

struct DefaultTableIdAllocatorCreator;

impl TableIdAllocatorCreator for DefaultTableIdAllocatorCreator {
    fn create(&self, kv_backend: &KvBackendRef) -> Arc<Sequence> {
        Arc::new(
            SequenceBuilder::new(TABLE_ID_SEQ, kv_backend.clone())
                .initial(MIN_USER_TABLE_ID as u64)
                .step(10)
                .build(),
        )
    }
}

#[async_trait]
pub trait ProcedureExecutorCreator: Send + Sync {
    async fn create(
        &self,
        ddl_manager: DdlManagerRef,
        procedure_manager: ProcedureManagerRef,
    ) -> Result<ProcedureExecutorRef>;
}

pub struct DefaultProcedureExecutorCreator;

#[async_trait]
impl ProcedureExecutorCreator for DefaultProcedureExecutorCreator {
    async fn create(
        &self,
        ddl_manager: DdlManagerRef,
        procedure_manager: ProcedureManagerRef,
    ) -> Result<ProcedureExecutorRef> {
        Ok(Arc::new(LocalProcedureExecutor::new(
            ddl_manager,
            procedure_manager,
        )))
    }
}

#[async_trait]
pub trait StandaloneLeaderServicesController: Send + Sync {
    /// Starts leader services that manage standalone metadata or WAL state.
    ///
    /// The default implementation starts the procedure manager and WAL provider
    /// during instance startup.
    async fn start(&self, context: LeaderServicesContext) -> Result<()>;

    /// Stops services started by [`StandaloneLeaderServicesController::start`].
    async fn stop(
        &self,
        procedure_manager: ProcedureManagerRef,
        region_server: RegionServer,
    ) -> Result<()>;
}

#[derive(Clone)]
/// Additional runtime handles for custom leader-service controllers.
///
/// The default standalone startup only needs to start/stop the procedure
/// manager and WAL provider. Some embedders need to do more work around
/// leader-service startup, for example reconciling metadata-backed runtime
/// state before publishing writable leadership. Grouping those handles here
/// keeps `Instance` small and avoids expanding
/// [`StandaloneLeaderServicesController::start`] every time a custom lifecycle
/// needs one more standalone component.
pub struct LeaderServicesContext {
    pub procedure_manager: ProcedureManagerRef,
    pub wal_provider: WalProviderRef,
    pub region_server: RegionServer,
    pub kv_backend: KvBackendRef,
    pub cache_registry: LayeredCacheRegistryRef,
    pub catalog_manager: CatalogManagerRef,
    pub flow_engine: FlowDualEngineRef,
    pub frontend_client: Arc<FrontendClient>,
    pub node_id: Option<DatanodeId>,
    pub init_regions_parallelism: usize,
    pub plugin_options: Vec<PluginOptions>,
}

pub struct DefaultStandaloneLeaderServicesController;

#[async_trait]
impl StandaloneLeaderServicesController for DefaultStandaloneLeaderServicesController {
    async fn start(&self, context: LeaderServicesContext) -> Result<()> {
        context
            .procedure_manager
            .start()
            .await
            .context(error::StartProcedureManagerSnafu)?;
        context
            .wal_provider
            .start()
            .await
            .context(error::StartWalProviderSnafu)
    }

    async fn stop(
        &self,
        procedure_manager: ProcedureManagerRef,
        _region_server: RegionServer,
    ) -> Result<()> {
        procedure_manager
            .stop()
            .await
            .context(error::StopProcedureManagerSnafu)
    }
}

/// `InstanceCreator` is used for grouping various component creators for building the
/// Standalone instance, suitable for customizing how the instance can be built.
pub struct InstanceCreator {
    /// Hook for replacing metadata KV construction while reusing the rest of the
    /// standalone build flow.
    metadata_kv_backend_creator: Box<dyn MetadataKvBackendCreator>,
    node_manager_creator: Box<dyn NodeManagerCreator>,
    table_id_allocator_creator: Box<dyn TableIdAllocatorCreator>,
    procedure_executor_creator: Box<dyn ProcedureExecutorCreator>,
    leader_services_controller: Box<dyn StandaloneLeaderServicesController>,
    open_regions_writable_override: Option<bool>,
}

impl InstanceCreator {
    pub fn new(
        node_manager_creator: Box<dyn NodeManagerCreator>,
        table_id_allocator_creator: Box<dyn TableIdAllocatorCreator>,
        procedure_executor_creator: Box<dyn ProcedureExecutorCreator>,
    ) -> Self {
        Self {
            metadata_kv_backend_creator: Box::new(DefaultMetadataKvBackendCreator),
            node_manager_creator,
            table_id_allocator_creator,
            procedure_executor_creator,
            leader_services_controller: Box::new(DefaultStandaloneLeaderServicesController),
            open_regions_writable_override: None,
        }
    }

    pub fn with_metadata_kv_backend_creator(
        mut self,
        metadata_kv_backend_creator: Box<dyn MetadataKvBackendCreator>,
    ) -> Self {
        self.metadata_kv_backend_creator = metadata_kv_backend_creator;
        self
    }

    /// Wraps the metadata backend creator while retaining the default creator.
    ///
    /// This is useful for callers that need to add runtime behavior around
    /// metadata access without reimplementing backend selection.
    pub fn map_metadata_kv_backend_creator<F>(mut self, f: F) -> Self
    where
        F: FnOnce(Box<dyn MetadataKvBackendCreator>) -> Box<dyn MetadataKvBackendCreator>,
    {
        self.metadata_kv_backend_creator = f(self.metadata_kv_backend_creator);
        self
    }

    /// Wraps node-manager creation while preserving the selected standalone node manager.
    pub fn map_node_manager_creator<F>(mut self, f: F) -> Self
    where
        F: FnOnce(Box<dyn NodeManagerCreator>) -> Box<dyn NodeManagerCreator>,
    {
        self.node_manager_creator = f(self.node_manager_creator);
        self
    }

    /// Wraps procedure-executor creation while preserving the current setup.
    pub fn map_procedure_executor_creator<F>(mut self, f: F) -> Self
    where
        F: FnOnce(Box<dyn ProcedureExecutorCreator>) -> Box<dyn ProcedureExecutorCreator>,
    {
        self.procedure_executor_creator = f(self.procedure_executor_creator);
        self
    }

    /// Replaces startup/shutdown ownership for procedure manager and WAL provider.
    pub fn with_leader_services_controller(
        mut self,
        leader_services_controller: Box<dyn StandaloneLeaderServicesController>,
    ) -> Self {
        self.leader_services_controller = leader_services_controller;
        self
    }

    /// Overrides whether regions opened during startup should become writable.
    ///
    /// `None` keeps the default startup behavior (regions open writable).
    ///
    /// Warning: setting this to `false` in standalone mode will leave reopened regions
    /// permanently read-only. Standalone has no metasrv heartbeat or region-role
    /// reconciliation, so there is no path to promote regions to Leader after startup.
    pub fn with_open_regions_writable_override(mut self, writable: bool) -> Self {
        self.open_regions_writable_override = Some(writable);
        self
    }
}

impl Default for InstanceCreator {
    fn default() -> Self {
        Self {
            metadata_kv_backend_creator: Box::new(DefaultMetadataKvBackendCreator),
            node_manager_creator: Box::new(DefaultNodeManagerCreator),
            table_id_allocator_creator: Box::new(DefaultTableIdAllocatorCreator),
            procedure_executor_creator: Box::new(DefaultProcedureExecutorCreator),
            leader_services_controller: Box::new(DefaultStandaloneLeaderServicesController),
            open_regions_writable_override: None,
        }
    }
}

/// `InstanceCreatorResult` is expected to be used paired with [InstanceCreator].
/// It stores the created and other important components for further reusing.
pub struct InstanceCreatorResult {
    pub kv_backend: KvBackendRef,
    pub node_manager: NodeManagerRef,
    pub table_id_allocator: Arc<Sequence>,
}

#[cfg(test)]
mod tests {
    use std::default::Default;
    use std::io::Write;
    use std::time::Duration;

    use auth::{Identity, Password, UserProviderRef};
    use clap::{CommandFactory, Parser};
    use common_base::readable_size::ReadableSize;
    use common_config::ENV_VAR_SEP;
    use common_options::plugin_options::StandaloneFlag;
    use common_test_util::temp_dir::{create_named_temp_file, create_temp_dir};
    use common_wal::config::DatanodeWalConfig;
    use frontend::frontend::FrontendOptions;
    use object_store::config::{FileConfig, GcsConfig};
    use servers::grpc::GrpcOptions;

    use super::*;
    use crate::options::GlobalOptions;

    #[test]
    fn test_standalone_local_file_access_config() {
        let data_home = create_temp_dir("standalone_copy_root");
        let storage = StorageConfig {
            data_home: data_home.path().display().to_string(),
            ..Default::default()
        };
        let access = standalone_local_file_access(&storage).unwrap();
        assert_eq!(
            access.sandbox_root().unwrap(),
            data_home.path().join("copy").canonicalize().unwrap()
        );

        let remote_data_home = StorageConfig {
            data_home: "s3://bucket/data".to_string(),
            ..Default::default()
        };
        assert!(matches!(
            standalone_local_file_access(&remote_data_home).unwrap(),
            LocalFileAccess::Disabled
        ));

        let explicit_root = create_temp_dir("standalone_explicit_copy_root");
        let remote_with_explicit_root = StorageConfig {
            data_home: "s3://bucket/data".to_string(),
            copy_root: Some(explicit_root.path().display().to_string()),
            ..Default::default()
        };
        assert_eq!(
            standalone_local_file_access(&remote_with_explicit_root)
                .unwrap()
                .sandbox_root()
                .unwrap(),
            explicit_root.path().canonicalize().unwrap()
        );

        let remote_copy_root = StorageConfig {
            data_home: data_home.path().display().to_string(),
            copy_root: Some("s3://bucket/copy".to_string()),
            ..Default::default()
        };
        assert!(matches!(
            standalone_local_file_access(&remote_copy_root),
            Err(common_datasource::error::Error::InvalidLocalFileRootConfig { .. })
        ));

        let exposes_internal = StorageConfig {
            data_home: data_home.path().display().to_string(),
            copy_root: Some(data_home.path().join("data").display().to_string()),
            ..Default::default()
        };
        assert!(matches!(
            standalone_local_file_access(&exposes_internal),
            Err(common_datasource::error::Error::InvalidLocalFileRootConfig { .. })
        ));

        let exposes_data_home = StorageConfig {
            data_home: data_home.path().display().to_string(),
            copy_root: Some(data_home.path().parent().unwrap().display().to_string()),
            ..Default::default()
        };
        assert!(matches!(
            standalone_local_file_access(&exposes_data_home),
            Err(common_datasource::error::Error::InvalidLocalFileRootConfig { .. })
        ));
    }

    #[tokio::test]
    async fn test_try_from_start_command_to_anymap() {
        let fe_opts = FrontendOptions {
            user_provider: Some("static_user_provider:cmd:test=test".to_string()),
            ..Default::default()
        };

        let mut plugins = Plugins::new();
        plugins.insert(StandaloneFlag);
        plugins::setup_frontend_plugins_pre_build(&mut plugins, &[], &fe_opts, None)
            .await
            .unwrap();

        let provider = plugins.get::<UserProviderRef>().unwrap();
        let result = provider
            .authenticate(
                Identity::UserId("test", None),
                Password::PlainText("test".to_string().into()),
            )
            .await;
        let _ = result.unwrap();
    }

    #[test]
    fn test_toml() {
        let opts = StandaloneOptions::default();
        let toml_string = toml::to_string(&opts).unwrap();
        let _parsed: StandaloneOptions = toml::from_str(&toml_string).unwrap();
    }

    #[test]
    fn test_read_from_config_file() {
        let mut file = create_named_temp_file();
        let toml_str = r#"
            enable_memory_catalog = true

            [wal]
            provider = "raft_engine"
            dir = "./greptimedb_data/test/wal"
            file_size = "1GB"
            purge_threshold = "50GB"
            purge_interval = "10m"
            read_batch_size = 128
            sync_write = false

            [storage]
            data_home = "./greptimedb_data/"
            type = "File"

            [[storage.providers]]
            type = "Gcs"
            bucket = "foo"
            endpoint = "bar"

            [[storage.providers]]
            type = "S3"
            access_key_id = "access_key_id"
            secret_access_key = "secret_access_key"

            [storage.compaction]
            max_inflight_tasks = 3
            max_files_in_level0 = 7
            max_purge_tasks = 32

            [storage.manifest]
            checkpoint_margin = 9
            gc_duration = '7s'

            [http]
            addr = "127.0.0.1:4000"
            timeout = "33s"
            body_limit = "128MB"

            [opentsdb]
            enable = true

            [logging]
            level = "debug"
            dir = "./greptimedb_data/test/logs"
        "#;
        write!(file, "{}", toml_str).unwrap();
        let cmd = StartCommand {
            config_file: Some(file.path().to_str().unwrap().to_string()),
            user_provider: Some("static_user_provider:cmd:test=test".to_string()),
            ..Default::default()
        };

        let options = cmd
            .load_options(&GlobalOptions::default())
            .unwrap()
            .component;
        let fe_opts = options.frontend_options();
        let dn_opts = options.datanode_options();
        let logging_opts = options.logging;
        assert_eq!("127.0.0.1:4000".to_string(), fe_opts.http.addr);
        assert_eq!(Duration::from_secs(33), fe_opts.http.timeout);
        assert_eq!(ReadableSize::mb(128), fe_opts.http.body_limit);
        assert_eq!("127.0.0.1:4001".to_string(), fe_opts.grpc.bind_addr);
        assert!(fe_opts.mysql.enable);
        assert_eq!("127.0.0.1:4002", fe_opts.mysql.addr);
        assert_eq!(2, fe_opts.mysql.runtime_size);
        assert_eq!(None, fe_opts.mysql.reject_no_database);
        assert!(fe_opts.influxdb.enable);
        assert!(fe_opts.opentsdb.enable);

        let DatanodeWalConfig::RaftEngine(raft_engine_config) = dn_opts.wal else {
            unreachable!()
        };
        assert_eq!(
            "./greptimedb_data/test/wal",
            raft_engine_config.dir.unwrap()
        );

        assert!(matches!(
            &dn_opts.storage.store,
            object_store::config::ObjectStoreConfig::File(FileConfig { .. })
        ));
        assert_eq!(dn_opts.storage.providers.len(), 2);
        assert!(matches!(
            dn_opts.storage.providers[0],
            object_store::config::ObjectStoreConfig::Gcs(GcsConfig { .. })
        ));
        match &dn_opts.storage.providers[1] {
            object_store::config::ObjectStoreConfig::S3(s3_config) => {
                assert_eq!(
                    "SecretBox<alloc::string::String>([REDACTED])".to_string(),
                    format!("{:?}", s3_config.connection.access_key_id)
                );
            }
            _ => {
                unreachable!()
            }
        }

        assert_eq!("debug", logging_opts.level.as_ref().unwrap());
        assert_eq!("./greptimedb_data/test/logs".to_string(), logging_opts.dir);
    }

    #[test]
    fn test_load_log_options_from_cli() {
        let cmd = StartCommand {
            user_provider: Some("static_user_provider:cmd:test=test".to_string()),
            mysql_addr: Some("127.0.0.1:4002".to_string()),
            postgres_addr: Some("127.0.0.1:4003".to_string()),
            ..Default::default()
        };

        let opts = cmd
            .load_options(&GlobalOptions {
                log_dir: Some("./greptimedb_data/test/logs".to_string()),
                log_level: Some("debug".to_string()),

                #[cfg(feature = "tokio-console")]
                tokio_console_addr: None,
            })
            .unwrap()
            .component;

        assert_eq!("./greptimedb_data/test/logs", opts.logging.dir);
        assert_eq!("debug", opts.logging.level.unwrap());
    }

    #[test]
    fn test_config_precedence_order() {
        let mut file = create_named_temp_file();
        let toml_str = r#"
            [http]
            addr = "127.0.0.1:4000"

            [logging]
            level = "debug"
        "#;
        write!(file, "{}", toml_str).unwrap();

        let env_prefix = "STANDALONE_UT";
        temp_env::with_vars(
            [
                (
                    // logging.dir = /other/log/dir
                    [
                        env_prefix.to_string(),
                        "logging".to_uppercase(),
                        "dir".to_uppercase(),
                    ]
                    .join(ENV_VAR_SEP),
                    Some("/other/log/dir"),
                ),
                (
                    // logging.level = info
                    [
                        env_prefix.to_string(),
                        "logging".to_uppercase(),
                        "level".to_uppercase(),
                    ]
                    .join(ENV_VAR_SEP),
                    Some("info"),
                ),
                (
                    // http.addr = 127.0.0.1:24000
                    [
                        env_prefix.to_string(),
                        "http".to_uppercase(),
                        "addr".to_uppercase(),
                    ]
                    .join(ENV_VAR_SEP),
                    Some("127.0.0.1:24000"),
                ),
            ],
            || {
                let command = StartCommand {
                    config_file: Some(file.path().to_str().unwrap().to_string()),
                    http_addr: Some("127.0.0.1:14000".to_string()),
                    env_prefix: env_prefix.to_string(),
                    ..Default::default()
                };

                let opts = command.load_options(&Default::default()).unwrap().component;

                // Should be read from env, env > default values.
                assert_eq!(opts.logging.dir, "/other/log/dir");

                // Should be read from config file, config file > env > default values.
                assert_eq!(opts.logging.level.as_ref().unwrap(), "debug");

                // Should be read from cli, cli > config file > env > default values.
                let fe_opts = opts.frontend_options();
                assert_eq!(fe_opts.http.addr, "127.0.0.1:14000");
                assert_eq!(ReadableSize::mb(64), fe_opts.http.body_limit);

                // Should be default value.
                assert_eq!(fe_opts.grpc.bind_addr, GrpcOptions::default().bind_addr);
            },
        );
    }

    #[test]
    fn test_parse_grpc_bind_addr_aliases() {
        let command =
            StartCommand::try_parse_from(["standalone", "--grpc-bind-addr", "127.0.0.1:14001"])
                .unwrap();
        assert_eq!(command.grpc_bind_addr.as_deref(), Some("127.0.0.1:14001"));

        let command =
            StartCommand::try_parse_from(["standalone", "--rpc-bind-addr", "127.0.0.1:24001"])
                .unwrap();
        assert_eq!(command.grpc_bind_addr.as_deref(), Some("127.0.0.1:24001"));

        let command =
            StartCommand::try_parse_from(["standalone", "--rpc-addr", "127.0.0.1:34001"]).unwrap();
        assert_eq!(command.grpc_bind_addr.as_deref(), Some("127.0.0.1:34001"));
    }

    #[test]
    fn test_help_uses_grpc_option_names() {
        let mut cmd = StartCommand::command();
        let mut help = Vec::new();
        cmd.write_long_help(&mut help).unwrap();
        let help = String::from_utf8(help).unwrap();

        assert!(help.contains("--grpc-bind-addr"));
        assert!(!help.contains("--rpc-bind-addr"));
        assert!(!help.contains("--rpc-addr"));
    }

    #[test]
    fn test_load_default_standalone_options() {
        let options =
            StandaloneOptions::load_layered_options(None, "GREPTIMEDB_STANDALONE").unwrap();
        let default_options = StandaloneOptions::default();
        assert_eq!(options.enable_telemetry, default_options.enable_telemetry);
        assert_eq!(options.http, default_options.http);
        assert_eq!(options.grpc, default_options.grpc);
        assert_eq!(options.mysql, default_options.mysql);
        assert_eq!(options.postgres, default_options.postgres);
        assert_eq!(options.opentsdb, default_options.opentsdb);
        assert_eq!(options.influxdb, default_options.influxdb);
        assert_eq!(options.prom_store, default_options.prom_store);
        assert_eq!(options.wal, default_options.wal);
        assert_eq!(options.metadata_store, default_options.metadata_store);
        assert_eq!(options.procedure, default_options.procedure);
        assert_eq!(options.logging, default_options.logging);
        assert_eq!(options.region_engine, default_options.region_engine);
    }

    #[test]
    fn test_cache_config() {
        let toml_str = r#"
            [storage]
            data_home = "test_data_home"
            type = "S3"
            [storage.cache_config]
            enable_read_cache = true
        "#;
        let mut opts: StandaloneOptions = toml::from_str(toml_str).unwrap();
        opts.sanitize();
        assert!(opts.storage.store.cache_config().unwrap().enable_read_cache);
        assert_eq!(
            opts.storage.store.cache_config().unwrap().cache_path,
            "test_data_home"
        );
    }

    #[test]
    #[cfg(not(feature = "enterprise"))]
    fn test_load_options_ignores_unknown_plugin_options() {
        // Plugin options that are not recognized by the current build (for example,
        // an enterprise plugin option seen by an open-source build) must not abort
        // startup. They should be dropped with a warning instead.
        let mut file = create_named_temp_file();
        write!(
            file,
            r#"
[[plugins]]
SomeUnknownPlugin = {{ feature = "foo", count = 5 }}

[[plugins]]
AnotherUnknownPlugin = {{}}
"#
        )
        .unwrap();

        let opts = GreptimeOptions::<StandaloneOptions>::load_layered_options(
            Some(file.path().to_str().unwrap()),
            "GREPTIMEDB_STANDALONE_UT",
        )
        .expect(
            "loading a config with unrecognized plugin options should succeed, \
             ignoring the unknown ones",
        );
        // Unknown plugin options are dropped; the recognized list is empty in the
        // open-source build.
        assert!(opts.plugins.is_empty());
    }

    #[test]
    fn test_load_options_errors_on_malformed_known_plugin_option() {
        // A *known* variant with a malformed payload must NOT be silently
        // dropped; config loading must fail so a misconfigured plugin is not
        // disabled without notice. Here `Dummy` (a unit variant) is given a map
        // payload, which is invalid.
        let mut file = create_named_temp_file();
        write!(
            file,
            r#"
[[plugins]]
Dummy = {{ unexpected = "payload" }}
"#
        )
        .unwrap();

        let result = GreptimeOptions::<StandaloneOptions>::load_layered_options(
            Some(file.path().to_str().unwrap()),
            "GREPTIMEDB_STANDALONE_UT",
        );
        assert!(
            result.is_err(),
            "a malformed payload for a known plugin variant must fail config loading"
        );
    }

    #[test]
    #[cfg(not(feature = "enterprise"))]
    fn test_load_options_ignores_multi_key_unknown_plugin_entry() {
        // A single plugin table carrying several *unknown* keys must not abort
        // startup with serde's "expected map with a single key" error; it is
        // dropped like any other unrecognized plugin option.
        let mut file = create_named_temp_file();
        write!(
            file,
            r#"
[[plugins]]
FirstUnknownPlugin = {{ a = 1 }}
SecondUnknownPlugin = {{ b = 2 }}
"#
        )
        .unwrap();

        let opts = GreptimeOptions::<StandaloneOptions>::load_layered_options(
            Some(file.path().to_str().unwrap()),
            "GREPTIMEDB_STANDALONE_UT",
        )
        .expect(
            "loading a config with a multi-key unknown plugin entry should succeed, \
             ignoring the unknown ones",
        );
        assert!(opts.plugins.is_empty());
    }
}
