SDK gRPC client module.

SDK gRPC client is a supervised gRPC connections pool that connects to the Temporal server Frontend Service gRPC service handler port (default 7233). Each SDK cluster owns its individual SDK gRPC client.

SDK gRPC Client Configuration

adapter - temporal_sdk_grpc:adapter/0 configuration of the HTTP/2 adapter used to handle gRPC requests. Default: {temporal_sdk_grpc_adapter_gun, []}.

pool_size - gRPC client connection pool size. When increasing the connection pool size, also consider increasing the OS file descriptor (FD) limits. Default: 10.

pool_strategy - gRPC client connection pool strategy, one of: round_robin or random. Default: round_robin.

grpc_opts - temporal_sdk_grpc:opts/0 gRPC request options for all gRPC requests except long-poll gRPC requests.

Default:

[
    {converter,
        {temporal_sdk_proto_converter, {
            %% default global payload codecs:
            [
                temporal_sdk_codec_payload_binary,
                temporal_sdk_codec_payload_json,
                temporal_sdk_codec_payload_erl
            ],
            %% custom payload codecs defined per messages list:
            [
                {
                    %% failure codecs
                    [
                        temporal_sdk_codec_payload_text
                    ],
                    %% failure messages
                    [
                        'temporal.api.failure.v1.ApplicationFailureInfo',
                        'temporal.api.failure.v1.CanceledFailureInfo',
                        'temporal.api.failure.v1.ResetWorkflowFailureInfo',
                        'temporal.api.failure.v1.TimeoutFailureInfo'
                    ]
                }
            ]
        }}},
    {codec, {temporal_sdk_codec_binaries, [], []}},
    {compressor, {temporal_sdk_grpc_compressor_identity, [], []}},
    {interceptor, {temporal_sdk_grpc_interceptor_identity, [], []}},
    {headers, #{
        <<"te">> => <<"trailers">>,
        <<"user-agent">> => temporal_sdk_utils:worker_version()
    }},
    {timeout, 5_000},
    {retry_policy, #{
        max_attempts => 3,
        backoff_coefficient => 2,
        initial_interval => 100,
        maximum_interval => 1_000,
        is_retryable => fun temporal_sdk_api:is_retryable/3
    }},
    {maximum_request_size, 4_100_000}
]

grpc_opts_longpoll - temporal_sdk_grpc:opts/0 overwrites for gRPC long-poll request options. Long-poll gRPC request options are evaluated by merging overwrites defined here with the values provided in the grpc_opts.

Temporal gRPC long-poll requests:

• PollActivityTaskQueue,
• PollWorkflowTaskQueue,
• PollNexusTaskQueue.

Default:

[
    {timeout, 70_000},
    {retry_policy, disabled}
]

helpers - gRPC request helpers. See gRPC Helpers section below for details.

Default:

[
    {id, fun temporal_sdk_api:id/4},
    {identity, fun temporal_sdk_api:identity/3},
    {to_payload_mapper, fun temporal_sdk_api:to_payload_mapper/5},
    {from_payload_mapper, fun temporal_sdk_api:from_payload_mapper/5},
    {serializer, fun temporal_sdk_api:serializer/4}
]

gRPC Helpers

SDK gRPC client gRPC helpers functions must be implemented as non-raising and non-blocking functions. Violating this requirement will cause SDK failures or unexpected behavior.

id - temporal_sdk_client:helpers_id_fun/0 function used to generate Temporal API gRPC request identifiers. See temporal_sdk_api:id/4 for the default SDK implementation.

identity - temporal_sdk_client:helpers_identity_fun/0 function used to generate Temporal API gRPC request worker or client identities. See temporal_sdk_api:identity/3 for the default SDK implementation.

to_payload_mapper - temporal_sdk_client:to_payload_mapper/0 function mapping from Erlang term temporal_sdk:term_to_payload/0 to Temporal payload temporal_sdk:temporal_payload/0. See temporal_sdk_api:to_payload_mapper/5 for the default SDK implementation.

from_payload_mapper - temporal_sdk_client:from_payload_mapper/0 function mapping from Temporal payload temporal_sdk:temporal_payload/0 to Erlang term temporal_sdk:term_from_payload/0. See temporal_sdk_api:from_payload_mapper/5 for the default SDK implementation.

serializer - temporal_sdk_client:helpers_serializer_fun/0 function used to serialize Erlang terms to Unicode characters before sending them to the Temporal server. See temporal_sdk_api:serializer/4 for the default SDK implementation.