feat(cron): cronworkflows when clause (#13474)

Signed-off-by: Isitha Subasinghe <[email protected]>

docs/fields.md

@@ -384,6 +384,8 @@ CronWorkflow is the definition of a scheduled workflow resource
 
 - [`cron-backfill.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-backfill.yaml)
 
+- [`cron-when.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-when.yaml)
+
 - [`cron-workflow.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-workflow.yaml)
 
 - [`dag-inline-cronworkflow.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/dag-inline-cronworkflow.yaml)
@@ -505,6 +507,8 @@ WorkflowSpec is the specification of a Workflow.
 
 - [`cron-backfill.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-backfill.yaml)
 
+- [`cron-when.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-when.yaml)
+
 - [`cron-workflow.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-workflow.yaml)
 
 - [`custom-metrics.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/custom-metrics.yaml)
@@ -948,6 +952,8 @@ CronWorkflowSpec is the specification of a CronWorkflow
 
 - [`cron-backfill.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-backfill.yaml)
 
+- [`cron-when.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-when.yaml)
+
 - [`cron-workflow.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-workflow.yaml)
 
 - [`custom-metrics.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/custom-metrics.yaml)
@@ -1253,6 +1259,7 @@ CronWorkflowSpec is the specification of a CronWorkflow
 |`successfulJobsHistoryLimit`|`integer`|SuccessfulJobsHistoryLimit is the number of successful jobs to be kept at a time|
 |`suspend`|`boolean`|Suspend is a flag that will stop new CronWorkflows from running if set to true|
 |`timezone`|`string`|Timezone is the timezone against which the cron schedule will be calculated, e.g. "Asia/Tokyo". Default is machine's local time.|
+|`when`|`string`|v3.6 and after: When is an expression that determines if a run should be scheduled.|
 |`workflowMetadata`|[`ObjectMeta`](#objectmeta)|WorkflowMetadata contains some metadata of the workflow to be run|
 |`workflowSpec`|[`WorkflowSpec`](#workflowspec)|WorkflowSpec is the spec of the workflow to be run|
 
@@ -4625,6 +4632,8 @@ ObjectMeta is metadata that all persisted resources must have, which includes al
 
 - [`cron-backfill.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-backfill.yaml)
 
+- [`cron-when.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-when.yaml)
+
 - [`cron-workflow.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-workflow.yaml)
 
 - [`custom-metrics.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/custom-metrics.yaml)
@@ -5244,6 +5253,8 @@ A single application container that you want to run within a pod.
 
 - [`continue-on-fail.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/continue-on-fail.yaml)
 
+- [`cron-when.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-when.yaml)
+
 - [`cron-workflow.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-workflow.yaml)
 
 - [`custom-metrics.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/custom-metrics.yaml)
@@ -5945,6 +5956,8 @@ PersistentVolumeClaimSpec describes the common attributes of storage devices and
 
 - [`cron-backfill.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-backfill.yaml)
 
+- [`cron-when.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-when.yaml)
+
 - [`cron-workflow.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/cron-workflow.yaml)
 
 - [`custom-metrics.yaml`](https://github.com/argoproj/argo-workflows/blob/main/examples/custom-metrics.yaml)

docs/variables.md

@@ -184,6 +184,20 @@ Only available for `successCondition`
 | `response.body` | Response body (`string`) |
 | `response.headers` | Response headers (`map[string][]string`) |
 
+### CronWorkflows
+
+> v3.6 and after
+
+| Variable | Description|
+|----------|------------|
+| `cronworkflow.name` | Name of the CronWorkflow (`string`) |
+| `cronworkflow.namespace` | Namespace of the CronWorkflow (`string`) |
+| `cronworkflow.labels.<NAME>` | CronWorkflow labels (`string`) |
+| `cronworkflow.labels.json` | CronWorkflow labels as a JSON string (`string`) |
+| `cronworkflow.annotations.<NAME>` | CronWorkflow annotations (`string`) |
+| `cronworkflow.annotations.json` | CronWorkflow annotations as a JSON string (`string`) |
+| `cronworkflow.lastScheduledTime` | The time since this workflow was last scheduled, value is nil on first run (`*time.Time`) |
+
 ### `RetryStrategy`
 
 When using the `expression` field within `retryStrategy`, special variables are available.

examples/cron-when.yaml

@@ -0,0 +1,16 @@
+apiVersion: argoproj.io/v1alpha1
+kind: CronWorkflow
+metadata:
+  name: sleep-when
+spec:
+  schedule: "* * * * *"
+  concurrencyPolicy: "Allow"
+  when: "{{= cronworkflow.lastScheduledTime == nil || (now() - cronworkflow.lastScheduledTime).Seconds() > 360 }}"
+  workflowSpec:
+    entrypoint: sleep-busybox
+    templates:
+      - name: sleep-busybox
+        container:
+          image: busybox
+          command: [sleep]
+          args: ["10"]

pkg/apis/workflow/v1alpha1/cron_workflow_types.go

@@ -65,6 +65,8 @@ type CronWorkflowSpec struct {
 	StopStrategy *StopStrategy `json:"stopStrategy,omitempty" protobuf:"bytes,10,opt,name=stopStrategy"`
 	// Schedules is a list of schedules to run the Workflow in Cron format
 	Schedules []string `json:"schedules,omitempty" protobuf:"bytes,11,opt,name=schedules"`
+	// v3.6 and after: When is an expression that determines if a run should be scheduled.
+	When string `json:"when,omitempty" protobuf:"bytes,12,opt,name=when"`
 }
 
 // v3.6 and after: StopStrategy defines if the CronWorkflow should stop scheduling based on a condition