Google Cloud Platform Spanner

Scale applications based on the result of a Google Cloud Spanner SQL query.

Availability: 2.21+ Maintainer: Community

Trigger Specification

This specification describes the gcp-spanner trigger for Google Cloud Spanner.

triggers:
- type: gcp-spanner
  metadata:
    projectId: my-gcp-project          # Required
    instanceId: my-spanner-instance    # Required
    databaseId: my-database            # Required
    query: "SELECT COUNT(*) FROM jobs WHERE status = 'pending'"  # Required
    targetValue: "5"                   # Optional - Default: 5
    activationValue: "0"               # Optional - Default: 0
    credentialsFromEnv: GOOGLE_APPLICATION_CREDENTIALS_JSON  # Optional
    credentialsFromEnvFile: GOOGLE_APPLICATION_CREDENTIALS_JSON # Optional

Parameter list:

projectId - The GCP project that owns the Spanner instance.
instanceId - The Spanner instance ID.
databaseId - The Spanner database ID.
query - A SQL statement that returns exactly one row with one INT64 column. When the query matches no rows the value is treated as 0.
targetValue - Average target value to trigger scaling actions. Must be greater than 0. (Default: 5, Optional)
activationValue - Target value for activating the scaler. Learn more about activation here. (Default: 0, Optional)

The metric name will be generated automatically based on the trigger index and the resource identifiers, for example: s0-gcp-spanner-instanceId-databaseId-projectId.

You can provide in the metadata either credentialsFromEnv or credentialsFromEnvFile.

credentialsFromEnv - Set to the name of the environment variable that holds the credential information.
credentialsFromEnvFile - Set to the name of a json file that holds the credential information.

Authentication Parameters

You can use TriggerAuthentication CRD to configure the authentication by providing the service account credentials in JSON.

Credential based authentication:

GoogleApplicationCredentials - Service account credentials in JSON.

Identity based authentication:

You can also use TriggerAuthentication CRD to configure the authentication using the associated service account of the running machine in Google Cloud. You only need to create a TriggerAuthentication as this example, and reference it in the ScaledObject. ClusterTriggerAuthentication can also be used if you intend to use it globally in your cluster.

Examples

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: spanner-scaledobject
  namespace: my-namespace
spec:
  scaleTargetRef:
    name: job-processor
  triggers:
  - type: gcp-spanner
    metadata:
      projectId: my-gcp-project
      instanceId: my-spanner-instance
      databaseId: my-database
      query: "SELECT COUNT(*) FROM jobs WHERE status = 'pending'"
      targetValue: "5"
      credentialsFromEnv: GOOGLE_APPLICATION_CREDENTIALS_JSON

Use TriggerAuthentication with Kubernetes secret

apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-gcp-credentials
spec:
  secretTargetRef:
  - parameter: GoogleApplicationCredentials
    name: gcp-spanner-secret        # Required. Refers to the name of the secret
    key: GOOGLE_APPLICATION_CREDENTIALS_JSON       # Required.
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: spanner-scaledobject
spec:
  scaleTargetRef:
    name: job-processor
  triggers:
  - type: gcp-spanner
    authenticationRef:
      name: keda-trigger-auth-gcp-credentials
    metadata:
      projectId: my-gcp-project
      instanceId: my-spanner-instance
      databaseId: my-database
      query: "SELECT COUNT(*) FROM jobs WHERE status = 'pending'"
      targetValue: "5"

Use TriggerAuthentication with GCP Identity

apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-gcp-credentials
spec:
  podIdentity:
    provider: gcp
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: spanner-scaledobject
spec:
  scaleTargetRef:
    name: job-processor
  triggers:
  - type: gcp-spanner
    authenticationRef:
      name: keda-trigger-auth-gcp-credentials
    metadata:
      projectId: my-gcp-project
      instanceId: my-spanner-instance
      databaseId: my-database
      query: "SELECT COUNT(*) FROM jobs WHERE status = 'pending'"
      targetValue: "5"