Cloud Run with a gRPC probe

- 3 minutes read - 428 words

Cloud Run supports gRPC startup|liveness probes which I’d not used before.

I’m using Cloud Run v2 and specifically projects.locations.services.create and Service

PROJECT="..."
REGION="..."
REPO=".."

# Must be in an Artifact Registry repo
IMAGE="${REGION}-docker.pkg.dev/${PROJECT}/${REPO}/..."

# Run v2
ENDPOINT="https://run.googleapis.com/v2"

PARENT="projects/${PROJECT}/locations/${REGION}"

SERVICE="..."

I like to use Jsonnet (specifically go-jsonnet) to help templating Kubernetes(-like) deployments.

cloudrun.jsonnet:

local project = std.extVar("project");
local region = std.extVar("region");
local service = std.extVar("service");
local image = std.extVar("image");

local port = 8080;
local health_checking_service = "foo";

{
    "labels":{
        "type": "test"
    },
    "annotations": {
        "type": "test"
    },
    "template":{
        "containers": {
            "name": service,
            "image": image,
            "args": [],
            "resources": {
                "limits": {
                    "cpu": "1000m",
                    "memory": "512Mi"
                }
            },
            "ports": [
                {
                    "name": "http1",
                    "containerPort": port
                }
            ],
            "startupProbe": {
                "grpc": {
                    "port": port,
                    "service": health_checking_service
                }
            }
        },
        "scaling": {
            "maxInstanceCount": 1
        }
    }
}

And deploy it using:

# Once every hour
TOKEN=$(gcloud auth print-access-token)

jsonnet cloudrun.jsonnet \
--ext-str image="${IMAGE}" \
--ext-str project="${PROJECT}" \
--ext-str region="${REGION}" \
--ext-str service="${SERVICE}" \
| curl \
  --request POST \
  --header "Authorization: Bearer ${TOKEN}" \
  --header "Content-Type: application/json" \
  --header "Accept: application/json" \
  --data @- \
  "${ENDPOINT}/${PARENT}/services?serviceId=${SERVICE}&validateOnly=false"

NOTE You can’t combine --data-urlencode with --request POST and so the querystring parameters are embedded in the URL.

The output will be an Operation:

{
  "name": "projects/{PROJECT}/locations/{REGION}/operations/{ID}}",
  "metadata": {
    "@type": "type.googleapis.com/google.cloud.run.v2.Service",
    "name": "projects/{PROJECT}/locations/{REGION}/services/{SERVICE}",
    "uid": "{UID}",
    "generation": "1",
    "labels": {},
    "annotations": {},
    "createTime": "YYYY-MM-DDTHH:MM:SS.000000Z",
    "updateTime": "YYYY-MM-DDTHH:MM:SS.000000Z",
    "creator": "my@email.com",
    "lastModifier": "my@email.com",
    "launchStage": "GA",
    "template": {
      "scaling": {
        "maxInstanceCount": 1
      },
      "timeout": "300s",
      "serviceAccount": "{EMAIL}",
      "containers": [
        {
          "name": "{SERVICE}",
          "image": "{REGION}-docker.pkg.dev/{PROJECT}/{REPO}/{IMAGE}",
          "args": [],
          "resources": {
            "limits": {
              "cpu": "1000m",
              "memory": "512Mi"
            }
          },
          "ports": [
            {
              "name": "http1",
              "containerPort": 8080
            }
          ],
          "startupProbe": {
            "timeoutSeconds": 1,
            "periodSeconds": 10,
            "failureThreshold": 3,
            "grpc": {
              "port": 8080,
              "service": "foo"
            }
          }
        }
      ],
      "maxInstanceRequestConcurrency": 80
    },
    "traffic": [
      {
        "type": "TRAFFIC_TARGET_ALLOCATION_TYPE_LATEST",
        "percent": 100
      }
    ],
    "urls": [
      "https://{SERVICE}-{NUMBER}.{REGION}.run.app"
    ],
    "terminalCondition": {
      "state": "CONDITION_PENDING"
    },
    "reconciling": true,
    "etag": "..."
  }
}

Doing this, I notice that Cloud Run now provides deterministic ({SERVICE}-{NUMBER}.{REGION}.run.app) URLs which is good.

You can grab the service’s logs:

FILTER="
  resource.type=\"cloud_run_revision\"
  resource.labels.service_name=\"${SERVICE}\"
  resource.labels.location=\"${REGION}\"
  textPayload=~\"^STARTUP GRPC probe\"
"
gcloud logging read "${FILTER}" \
--project=${PROJECT} \
--format="value(textPayload)" \
--order=asc

STARTUP GRPC probe succeeded after 1 attempt for container "{SERVICE}" on port {PORT}.
STARTUP GRPC probe succeeded after 1 attempt for container "{SERVICE}" on port {PORT}.
STARTUP GRPC probe succeeded after 1 attempt for container "{SERVICE}" on port {PORT}.
STARTUP GRPC probe succeeded after 1 attempt for container "{SERVICE}" on port {PORT}.

If necessary, delete the Service once you’re done:

gcloud run services delete ${SERVICE} \
--region=${REGION} \
--project=${PROJECT} \
--quiet

That’s all!