This Stackoverflow question piqued my interest:

retry policy configuration for grpc not working

Service Config in gRPC is new to me but, my initial suspicion (albeit incorrect) was that the JSON types were incorrect.

I decided to try using the Protocol Buffer source service_config.proto to verify the JSON.

To do so I needed to compile the source…. it was gnarly.

There are 2 repos used:

• googleapis
• grpc-proto

The service_config.proto includes options for java_package but no go_package.

Referring to Accessing Google Services using gRPC, I wanted to query a project’s Cloud Logging for log-based metrics using gRPC.

In summary:

ENDPOINT="logging.googleapis.com:443"

ROOT="/path/to/googleapis" # https://github.com/googleapis/googleapis
PACKAGE="google/logging/v2"

# NB Not logging.proto
PROTO="${ROOT}/${PACKAGE}/logging_metrics.proto"

TOKEN=$(gcloud auth print-access-token)

PROJECT="..."

PACKAGE="google.logging.v2"
SERVICE="MetricsServiceV2"
METHOD="${PACKAGE}.${SERVICE}/ListLogMetrics"

# ListLogMetricsRequest fields
PARENT="projects/${PROJECT}"

grpcurl \
--import-path=${ROOT} \
--proto=${PROTO} \
-H "Authorization: Bearer ${TOKEN}" \
-d "{\"parent\": \"${PARENT}\"}" \
${ENDPOINT} ${METHOD}

From APIs Explorer, Cloud Logging API v2, instead of the REST reference, browse the gRPC reference specifically the package google.logging.v2 which includes MetricsServiceV2. We’re interested in the ListLogMetrics method (which unfortunately isn’t directly hyperlinkable) but is defined to be:

Google publishes interface definitions of Google APIs (services) that support REST and gRPC in a repo called Google APIs. Google’s SDKs uses gRPC to access these services but, how to do this using e.g. gRPCurl?

I wanted to debug Cloud Profiler and its agent makes UpdateProfile RPCs to cloudprofiler.googleapis.com. Cloud Profiler is more challenging service to debug because (a) it’s publicly “write-only”; and (b) it has complex messages. UpdateProfile sends UpdateProfileRequest messages that include Profile messages that include profile_bytes which are gzip compressed serialized protos of pprof’s Profile.