components::ClickHouse Class Reference

#include <userver/storages/clickhouse/component.hpp>

Detailed Description

ClickHouse client component.

Provides access to a ClickHouse cluster.

Static configuration example:

# yaml
        clickhouse-database:
            secdist_alias: clickhouse-database-alias
            initial_pool_size: 5
            max_pool_size: 10
            queue_timeout: 1s
            use_secure_connection: false
            compression: lz4

If the component is configured with an secdist_alias, it will lookup connection data in secdist.json via secdist_alias value, otherwise via components name.

Secdist format

A ClickHouse alias in secdist is described as a JSON object clickhouse_settings, containing descriptions of databases.

import json
 
import pytest
 
from testsuite.databases.clickhouse import discover
 
pytest_plugins = ['pytest_userver.plugins.clickhouse']
 
 
@pytest.fixture(scope='session')
def service_env(clickhouse_conn_info) -> dict:
    secdist_config = {
        'clickhouse_settings': {
            'clickhouse-database-alias': {
                'hosts': [clickhouse_conn_info.host],
                'port': clickhouse_conn_info.tcp_port,
                'password': '',
                'user': 'default',
                'dbname': 'clickhouse-database',
            },
        },
    }
 
    return {'SECDIST_CONFIG': json.dumps(secdist_config)}
 
 
@pytest.fixture(scope='session')
def clickhouse_local(service_source_dir):
    return discover.find_schemas(
        schema_dirs=[service_source_dir.joinpath('schemas', 'clickhouse')],
        dbprefix='',
    )

Static options:

Name	Description	Default value
secdist_alias	name of the key in secdist config	components name
initial_pool_size	number of connections created initially	5
max_pool_size	maximum number of created connections	10
queue_timeout	client waiting for a free connection time limit	1s
use_secure_connection	whether to use TLS for connections	true
compression	compression method to use (none / lz4)	none

Definition at line 57 of file component.hpp.

Inheritance diagram for components::ClickHouse:

Public Member Functions
	ClickHouse (const ComponentConfig &, const ComponentContext &)
	Component constructor.
	~ClickHouse () override
	Component destructor.
std::shared_ptr< storages::clickhouse::Cluster >	GetCluster () const
	Cluster accessor.
ComponentHealth	GetComponentHealth () const override
void	OnLoadingCancelled () override
void	OnAllComponentsLoaded () override
void	OnAllComponentsAreStopping () override

Static Public Member Functions
static yaml_config::Schema	GetStaticConfigSchema ()

Protected Types
using	LoggableComponentBase = ComponentBase
	Legacy alias, use ComponentBase instead.

Member Typedef Documentation

LoggableComponentBase

using components::ComponentBase::LoggableComponentBase = ComponentBase

protectedinherited

Legacy alias, use ComponentBase instead.

Definition at line 67 of file component_base.hpp.

Member Function Documentation

GetComponentHealth()

ComponentHealth components::ComponentBase::GetComponentHealth ( ) const

inlineoverridevirtualinherited

Override this function to inform the world of the state of your component.

Warning

The function is called concurrently from multiple threads.

Reimplemented from components::RawComponentBase.

Reimplemented in server::handlers::Restart.

Definition at line 35 of file component_base.hpp.

OnAllComponentsAreStopping()

void components::ComponentBase::OnAllComponentsAreStopping ( )

inlineoverridevirtualinherited

Component may use this function to stop doing work before the stop of the components that depend on it.

Base components may override it and make final to do some work before the derived object constructor is called. Don't use it otherwise.

Reimplemented from components::RawComponentBase.

Reimplemented in urabbitmq::ConsumerComponentBase, and components::Server.

Definition at line 58 of file component_base.hpp.

OnAllComponentsLoaded()

void components::ComponentBase::OnAllComponentsLoaded ( )

inlineoverridevirtualinherited

Component may use this function to finalize registration of other components that depend on it (for example, handler components register in server component, and the latter uses OnAllComponentsLoaded() to start processing requests).

Base components may override it and make final to do some work after the derived object constructor is called. Don't use it otherwise.

Reimplemented from components::RawComponentBase.

Reimplemented in urabbitmq::ConsumerComponentBase, components::Server, and server::handlers::Ping.

Definition at line 51 of file component_base.hpp.

OnLoadingCancelled()

void components::ComponentBase::OnLoadingCancelled ( )

inlineoverridevirtualinherited

Called once if the creation of any other component failed. If the current component expects some other component to take any action with the current component, this call is a signal that such action may never happen due to components loading was cancelled. Application components might not want to override it.

Reimplemented from components::RawComponentBase.

Definition at line 42 of file component_base.hpp.

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The documentation for this class was generated from the following file:

• userver/storages/clickhouse/component.hpp