Clients are classes that provide interfaces for requesting and retrieving data usually from remote server.
All the clients are asynchronous. In other words, a request suspends the current engine::Task and other coroutines are processed on the task processor. The suspended task resumes execution on the task processor after the data was retrieved.
It is a common practice to return references or smart pointers to clients from a component. In such cases:
Classes | |
| class | clients::http::Client |
| HTTP client interface that returns a HTTP request builder from CreateRequest(). More... | |
| class | baggage::BaggageManager |
| class | clients::dns::Resolver |
| Caching DNS resolver implementation. More... | |
| class | clients::http::ClientCore |
| HTTP client that returns a HTTP request builder from CreateRequest(). More... | |
| class | clients::http::ClientWithMiddlewares |
| HTTP client that returns a HTTP request builder from CreateRequest() with applied middlewares. More... | |
| class | dynamic_config::Client |
| Client for the dynamic configs service. More... | |
| class | dynamic_config::Source |
| A client for easy dynamic config fetching in components. More... | |
| class | engine::subprocess::ProcessStarter |
| Creates a new OS subprocess and executes a command in it. More... | |
| class | fs::FsCacheClient |
| Class client for storing files in memory Usually retrieved from components::FsCache. More... | |
| class | os_signals::Processor |
| A client that allows to subscribe to OS signals SIGUSR1 and SIGUSR2. More... | |
| class | storages::secdist::SecdistConfig |
| Client to retrieve credentials from the components::Secdist. More... | |
| class | storages::secdist::Secdist |
| Client to retrieve credentials from the components::Secdist and to subscribe to their updates. More... | |
| class | utils::statistics::Storage |
| class | storages::mongo::Pool |
| MongoDB client pool. More... | |
| class | storages::postgres::Cluster |
| Interface for executing queries on a cluster of PostgreSQL servers. More... | |
| class | storages::redis::Client |
| Valkey or Redis client. More... | |
| class | storages::redis::SubscribeClient |
| Client that allows subscribing to Redis channel messages. More... | |
| class | storages::clickhouse::Cluster |
| Interface for executing queries on a cluster of ClickHouse servers. More... | |
| class | ugrpc::client::ClientFactory |
| Creates gRPC clients. More... | |
| class | ugrpc::client::GenericClient |
| Allows to talk to gRPC services (generic and normal) using dynamic method names. More... | |
| class | kafka::ConsumerScope |
| RAII class that used as interface for Apache Kafka Consumer interaction and proper lifetime management. More... | |
| class | kafka::Producer |
| Apache Kafka Producer Client. More... | |
| class | urabbitmq::Client |
| Interface for communicating with a RabbitMQ cluster. More... | |
| class | storages::mysql::Cluster |
| Client interface for a cluster of MySQL servers. Usually retrieved from components::MySQL. More... | |
| class | storages::sqlite::Client |
| Interface for executing queries on SQLite connection. Usually retrieved from components::SQLite. More... | |
| class | ydb::CoordinationClient |
| YDB Coordination Client. More... | |
| class | ydb::FederatedTopicClient |
| YDB Federated Topic Client. More... | |
| class | ydb::TopicClient |
| YDB Topic Client. More... | |
| class | s3api::Client |
Typedefs | |
| using | ugrpc::client::CompletionStatus = utils::expected<grpc::Status, SpecialCaseCompletionType> |
| Result type for gRPC client call completion. | |
Enumerations | |
| enum class | ugrpc::client::SpecialCaseCompletionType : std::uint8_t { ugrpc::client::SpecialCaseCompletionType::kNetworkError , ugrpc::client::SpecialCaseCompletionType::kTimeoutDeadlinePropagated , ugrpc::client::SpecialCaseCompletionType::kCancelled , ugrpc::client::SpecialCaseCompletionType::kAbandoned } |
| Special completion types for gRPC client calls that don't result in a normal grpc::Status. More... | |
| using ugrpc::client::CompletionStatus = utils::expected<grpc::Status, SpecialCaseCompletionType> |
Result type for gRPC client call completion.
Type alias for CompletionStatus. Represents either a normal gRPC status (value) or a special completion case (error).
Definition at line 75 of file completion_status.hpp.
|
strong |
Special completion types for gRPC client calls that don't result in a normal grpc::Status.
This enum represents exceptional completion scenarios that occur during gRPC client calls when the RPC doesn't complete with a standard gRPC status. These cases are distinguished from normal status codes to provide more precise information about the nature of the failure.
| Enumerator | |
|---|---|
| kNetworkError | The RPC was interrupted at the network/transport level without a gRPC status. [special_cases_declaration] The call did not finish with a gRPC status from the server: the connection was lost, reset or otherwise interrupted. This is distinct from grpc::StatusCode::UNAVAILABLE, which is a valid gRPC status. For a unary call this is reported only when no concrete gRPC status is available and the response could not be obtained (not received, or received but not parseable). Whenever a concrete status is available instead (for example UNAVAILABLE or CANCELLED), it is reported as that grpc::Status rather than as this special case. Surfaces to the caller as ugrpc::client::RpcInterruptedError; for unary calls it is retryable. |
| kTimeoutDeadlinePropagated | Request timed out with deadline propagation enabled. This is distinguished from a regular grpc::StatusCode::DEADLINE_EXCEEDED to indicate that the timeout was due to propagated deadline from upstream request. |
| kCancelled | RPC was explicitly cancelled by the client. |
| kAbandoned | RPC was abandoned without proper completion. The RPC object was destroyed before the call could complete normally. This happens when:
|
Definition at line 26 of file completion_status.hpp.
