Trigger Specification

This specification describes the gcp-storage scaler, which scales Kubernetes workloads based on the count of objects in a given Google Cloud Storage (GCS) bucket. This scaler assumes the worker, when run, will process and clear the bucket by deleting/moving objects therein.

triggers: - type: gcp-storage  metadata:  bucketName: test-bucket  targetObjectCount: '100'  maxBucketItemsToScan: '1000'  credentialsFromEnv: GOOGLE_APPLICATION_CREDENTIALS_JSON # Optional  credentialsFromEnvFile: GOOGLE_APPLICATION_CREDENTIALS_JSON # Optional 

Parameter list:

• bucketName - Name of the bucket in GCS.
• targetObjectCount - Average target value to trigger scaling actions. (Default: 100, Optional)
• maxBucketItemsToScan - When to stop counting how many objects are in the bucket. (Default: 1000, Optional) As counting the number of objects involves iterating over their metadata it is advised to set this number to the value of targetObjectCount * maxReplicaCount.

The metric name will be generated automatically based on the trigger index and bucketName, for example: s0-gcp-storage-bucketName.

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 authenticate 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: gcp-storage-scaledobject  namespace: keda-gcp-storage-test spec:  scaleTargetRef:  name: keda-gcp-storage-go  triggers:  - type: gcp-storage  metadata:  bucketName: "Transactions"  targetObjectCount: "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-storage-secret # Required. Refers to the name of the secret  key: GOOGLE_APPLICATION_CREDENTIALS_JSON # Required. --- apiVersion: keda.sh/v1alpha1 kind: ScaledObject metadata:  name: gcp-storage-scaledobject spec:  scaleTargetRef:  name: keda-gcp-storage-go  triggers:  - type: gcp-storage  authenticationRef:  name: keda-trigger-auth-gcp-credentials  metadata:  bucketName: "Transactions"  targetObjectCount: "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: gcp-storage-scaledobject spec:  scaleTargetRef:  name: keda-gcp-storage-go  triggers:  - type: gcp-storage  authenticationRef:  name: keda-trigger-auth-gcp-credentials  metadata:  bucketName: "Transactions"  targetObjectCount: "5"