components::Redis Class Reference

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

Detailed Description

Redis client component.

Provides access to a redis cluster.

Dynamic options:

• REDIS_COMMANDS_BUFFERING_SETTINGS
• REDIS_DEFAULT_COMMAND_CONTROL
• REDIS_METRICS_SETTINGS
• REDIS_PUBSUB_METRICS_SETTINGS
• REDIS_RETRY_BUDGET_SETTINGS
• REDIS_REPLICA_MONITORING_SETTINGS
• REDIS_SUBSCRIBER_DEFAULT_COMMAND_CONTROL
• REDIS_SUBSCRIPTIONS_REBALANCE_MIN_INTERVAL_SECONDS
• REDIS_WAIT_CONNECTED

Static options:

Name	Description	Default value
thread_pools.redis_thread_pool_size	thread count to serve Redis requests	-
thread_pools.sentinel_thread_pool_size	thread count to serve sentinel requests.	-
groups	array of redis clusters to work with excluding subscribers	-
groups.[].config_name	key name in secdist with options for this cluster	-
groups.[].db	name to refer to the cluster in components::Redis::GetClient()	-
groups.[].sharding_strategy	one of RedisCluster, KeyShardCrc32, KeyShardTaximeterCrc32 or KeyShardGpsStorageDriver	"KeyShardTaximeterCrc32"
groups.[].allow_reads_from_master	allows read requests from master instance	false
subscribe_groups	array of redis clusters to work with in subscribe mode	-
subscribe_groups.[].config_name	key name in secdist with options for this cluster	-
subscribe_groups.[].db	name to refer to the cluster in components::Redis::GetSubscribeClient()	-
subscribe_groups.[].sharding_strategy	either RedisCluster or KeyShardTaximeterCrc32	"KeyShardTaximeterCrc32"

Static configuration example:

# yaml
redis:
    groups:
      - config_name: cats
        db: hello_service_cats_catalogue
        sharding_strategy: RedisCluster
      - config_name: dogs
        db: hello_service_dogs_catalogue
    subscribe_groups:
      - config_name: food
        db: hello_service_pet_food_orders
    thread_pools:
        redis_thread_pool_size: 8
        sentinel_thread_pool_size: 1

Secdist format

If a config_name option is provided, for example groups.some.config_name: some_name_of_your_database, then the Secdist entry for that alias should look like following:

{
  "redis_settings": {
    "some_name_of_your_database": {
      "password": "the_password_of_your_database",
      "sentinels": [
        {"host": "the_host1_of_your_database", "port": 11564}
      ],
      "shards": [
        {"name": "test_master0"}
      ]
    }
  }
}

Cluster Redis setup

Redis cluster is the new recommended way of setting up Redis servers with improved stability.

To start, set sharding_strategy: RedisCluster in the static config as shown above.

Secdist configuration is simplified:

1. "shards" field is ignored, you can specify an empty array there;
2. "sentinels" field should contain some of the cluster nodes. They are only used for topology discovery; it is not necessary to list all nodes.

Examples

samples/redis_service/redis_service.cpp.

Definition at line 127 of file component.hpp.

Inheritance diagram for components::Redis:

Public Member Functions
	Redis (const ComponentConfig &config, const ComponentContext &component_context)
std::shared_ptr< storages::redis::Client >	GetClient (const std::string &name, ::redis::RedisWaitConnected wait_connected={}) const
std::shared_ptr< redis::Sentinel >	Client (const std::string &name) const
std::shared_ptr< storages::redis::SubscribeClient >	GetSubscribeClient (const std::string &name, ::redis::RedisWaitConnected wait_connected={}) const
ComponentHealth	GetComponentHealth () const override
void	OnLoadingCancelled () override
void	OnAllComponentsLoaded () override
void	OnAllComponentsAreStopping () override

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

Static Public Attributes
static constexpr std::string_view	kName = "redis"
	The default name of components::Redis.

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/redis/component.hpp