gRPC

Configuration

The gRPC trigger is configurable using the grpc type and the following arguments:

Descriptor source

The descriptorSource field specifies the source from which to obtain the gRPC descriptor, which is necessary to make the gRPC call. Mtracer supports file and serverReflection as sources for the gRPC descriptor, which can be specified through the type field within descriptorSource.

File

If you use file as the source for the gRPC descriptor, you need to specify the path to the gRPC descriptor file through the protoPath field within descriptorSource.

Example:

descriptorSource:
    type: "file"
    protoPath: "./greeter.proto"

Server reflection

If you use serverReflection as the source for the gRPC descriptor, you simply need to specify the serverReflection type within descriptorSource, so that Mtracer will use the server reflection feature to obtain the gRPC descriptor directly from the gRPC server specified in the serverAddress argument.

Example:

descriptorSource:
    type: "serverReflection"

Method

The method field specifies the name of the gRPC method to call, which must be specified in the format package.service.method, for example helloworld.Greeter.SayHello.

Metadata

The metadata field specifies the metadata to include in the gRPC call, which must be specified as key-value pairs within a YAML map.

Example:

metadata:
    key1: "value1"
    key2: "value2"

Data

The data field specifies the gRPC request body, which must be specified in key-value format within a YAML map. This way, Mtracer will automatically convert the YAML map into a gRPC message according to the descriptor it has.

Example starting from a gRPC message defined as follows:

message RollRequest {
    string                    rollerName   = 1;
    google.protobuf.Timestamp rollTime     = 2;
    google.protobuf.Duration  rollDuration = 3;
}

This converts to a gRPC request body specified in YAML as follows:

data:
    rollerName: "Alice"
    rollTime: "2023-10-01T12:00:00Z"
    rollDuration: "10s"