如何在 Cloud Run 上使用 Stackdriver 日志记录

Question

I'm trying to get stackdriver logging working for a simple Go app running in Google Cloud Run (fully managed), but don't see stackdriver entries in CloudRun logs.

I've createdsimplest possible demo app based on "official" stackdriver golang example

Cloud Run docs states that no additional actions should be performed to write stackdriver logs

My service uses default service account

I'm using Go 1.13 to compile code (Dockerfile is copied from Cloud Run example "as-is")

I've tried to deploy it to different regions, with no success

When running container locally, using service account credentials, stackdriver log message does not appear in local terminal or stackdriver console

No matter what, on app start I see only "Before stackdriver logging" followed by "After stackdriver logging" with no other messages\errors in the middle

Here's part of logging code (use link above to get full source, Dockerfile and instructions to build and run the app):

import (
    "context"
    "log"
    "os"
    ...

    "cloud.google.com/go/compute/metadata"
    "cloud.google.com/go/logging"
)

func main() {
    loggingClient, err := stackdriverClient()
    ...
    log.Println("Before stackdriver logging")
    logger.StandardLogger(logging.Info).Println("Stackdriver log")
    if err = logger.Flush(); err != nil {
        log.Fatalf("Failed to flush client: %v", err)
    }
    if err = loggingClient.Close(); err != nil {
        log.Fatalf("Failed to close client: %v", err)
    }
    log.Println("After stackdriver logging")
    ...
}

func stackdriverClient() (client *logging.Client, err error) {
    var projectID string
    if projectID, err = metadata.ProjectID(); err == nil {
        client, err = logging.NewClient(context.Background(), projectID)
    }
    return
}

Answer 1

It turns out that log entries are written successfully
But default Cloud Run filter in logviewer web UI does not include them
Filter expression below worked for me to get all the logs:

resource.type = "project" OR resource.type = "cloud_run_revision"

(service name, location, severity omitted)

"stdout\stderr" log entries match resource.type="cloud_run_revision" , while stackdriver log entries match resource.type="project"

Update: I've created a ticket for this in google tracker

Answer 2

Since Cloud Run is already integrated with Cloud Logging, there is no need to use the Go Client Library. We run all our gRPC services on Cloud Run and use the following to ensure the logs are properly formatted in Cloud Logging:

package main

import (
    "github.com/rs/zerolog"
    "github.com/rs/zerolog/log"
    "os"
)

// initializeLogging sets up the logging configuration for the service.
// Invoke this method in your Init() method.
func initializeLogging() {
    // Set logging options for production development
    if os.Getenv("ENV") != "DEV" {
        // change the level field name to ensure these are parsed correctly in Stackdriver
        zerolog.LevelFieldName = "severity"
        // UNIX Time is faster and smaller than most timestamps
        zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
    } else {
        // Set logging options for local development
        log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
        zerolog.SetGlobalLevel(zerolog.DebugLevel)
    }
    
    // Example log
    log.Info().Msg("This is how you log at Info level")
}

The logs are then nicely displayed for local development.