Serilog.Sinks.GoogleCloudLogging

Serilog sink that writes events to Google Cloud Logging.

Built for netstandard2.0, net5.0

Release notes here: CHANGELOG.md

Getting started

Install package from Nuget:

dotnet add package Serilog.Sinks.GoogleCloudLogging

Configure Logger (using code):

var config = new GoogleCloudLoggingSinkOptions { ProjectId = "YOUR_PROJECT_ID", UseJsonOutput = true };
Log.Logger = new LoggerConfiguration().WriteTo.GoogleCloudLogging(config).CreateLogger();

Configure Logger (using config file):

This requires 'serilog-settings-configuration' to load sinks using an appsettings.json file.

"Serilog": {
  "Using": [ "Serilog.Sinks.GoogleCloudLogging" ],
  "MinimumLevel": "Information",
  "WriteTo": [
    {
      "Name": "GoogleCloudLogging",
      "Args": {
        "projectID": "YOUR_PROJECT_ID",
        "useJsonOutput": "true",
        "resourceType": "k8s_cluster",
        "resourceLabels": {
          "project_id": "PROJECT-ID-HERE-12345",
          "location": "LOCATION-STRING-HERE-region-name",
          "cluster_name": "CLUSTER-NAME-HERE-container-cluster"
        },
        "restrictedToMinimumLevel": "Warning"
      }
    }
  ]
}

var config = new ConfigurationBuilder().AddJsonFile("appsettings.json", optional: true, reloadOnChange: true).Build();
Log.Logger = new LoggerConfiguration().ReadFrom.Configuration(config).CreateLogger();

GCP authentication:

This library uses the Google-Cloud-Dotnet libraries which authenticate using the Application Default Credentials found on the host. This is automatic on GCE VMs or you can use the gcloud SDK to authenticate manually. The service account must have the Logs Writer permission to send logs.

Sink Options

Name	Default	Description
ProjectId		Google Cloud project ID where logs will be sent. Will be automatically set to host project if running in GCP, otherwise required.
ResourceType	global	Resource type for all log output. Will be automatically discovered if running in GCP, otherwise required. Must be one of the supported types listed in the cloud logging documentation.
LogName	Default	Name of the log. This is required if UseSourceContextAsLogName is false.
Labels		Dictionary<string, string> of properties added to all log entries.
ResourceLabels		Dictionary<string, string> of properties added to all log entries, at the resource level. See Monitored Resources and Services for recognized labels.
UseSourceContextAsLogName	True	The log name for a log entry will be set to the SourceContext property if it's available.
UseJsonOutput	False	Structured logs can be sent as text with labels or as a JSON object, see details below.
GoogleCredentialJson		GCP client libraries use Application Default Credentials. If these are not available or you need to use other credentials, set the JSON text of a credential file directly.
ServiceName		Name of the service added as metadata to log entries. Required to forward logged exceptions to Google Cloud Error Reporting. Must also set UseJsonOutput to true.
ServiceVersion		Version of the service added as metadata to log entries.

Output Type

Serilog uses structured logging which means each log line is a formatting template with attached properties that are combined to create the final output. When UseJsonOutput is false, the output is sent as TextPayload to GCP with any properties serialized to string key/value labels.

If UseJsonOutput is set to true, the output will be sent as JsonPayload to maintain the original data types. This is helpful for querying child properties or numeric values in the Log Viewer, and will also capture property names even if they have null values.

WARNING: JSON output only accepts numeric values as double so all numbers will be converted. Large integers and floating-point values will lose precision. If you want the exact value preserved then log it as a string instead.

Log Level Mapping

This table shows the mapping from Serilog LogLevel to Google Cloud Logging LogSeverity

Serilog	Cloud Logging
Verbose	Debug
Debug	Debug
Information	Info
Warning	Warning
Error	Error
Fatal	Critical

Viewing Logs

Logs will appear in the Google Cloud Console Log Viewer: https://console.cloud.google.com/logs/viewer