Introduce podGC strategy for deleting completed/successful pods (#1234)

api/openapi-spec/swagger.json

@@ -541,6 +541,14 @@
  }
  }
  },
+ "io.argoproj.workflow.v1alpha1.PodGC": {
+ "description": "PodGC describes how to delete completed pods as they complete",
+ "properties": {
+ "strategy": {
+ "type": "string"
+ }
+ }
+ },
  "io.argoproj.workflow.v1alpha1.RawArtifact": {
  "description": "RawArtifact allows raw string content to be placed as an artifact in a container",
  "required": [
@@ -1265,6 +1273,10 @@
  "type": "integer",
  "format": "int64"
  },
+ "podGC": {
+ "description": "PodGC describes the strategy to use when to deleting completed pods",
+ "$ref": "#/definitions/io.argoproj.workflow.v1alpha1.PodGC"
+ },
  "podPriority": {
  "description": "Priority to apply to workflow pods.",
  "type": "integer",

examples/pod-gc-strategy.yaml

@@ -0,0 +1,35 @@
+# pod gc provides the ability to delete pods automatically without deleting the workflow
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+ generateName: pod-gc-strategy-
+spec:
+ entrypoint: pod-gc-strategy
+
+ podGC:
+ # pod gc strategy must be one of the following
+ # * OnPodCompletion - delete pods immediately when pod is completed (including errors/failures)
+ # * OnPodSuccess - delete pods immediately when pod is successful
+ # * OnWorkflowCompletion - delete pods when workflow is completed
+ # * OnWorkflowSuccess - delete pods when workflow is successful
+ strategy: OnPodSuccess
+
+ templates:
+ - name: pod-gc-strategy
+ steps:
+ - - name: fail
+ template: fail
+ - name: succeed
+ template: succeed
+
+ - name: fail
+ container:
+ image: alpine:3.7
+ command: [sh, -c]
+ args: ["exit 1"]
+
+ - name: succeed
+ container:
+ image: alpine:3.7
+ command: [sh, -c]
+ args: ["exit 0"]

pkg/apis/workflow/v1alpha1/workflow_types.go

@@ -52,6 +52,17 @@ const (
  NodeTypeSuspend NodeType = "Suspend"
 )
 
+// PodGCStrategy is the strategy when to delete completed pods for GC.
+type PodGCStrategy string
+
+// PodGCStrategy
+const (
+ PodGCOnPodCompletion PodGCStrategy = "OnPodCompletion"
+ PodGCOnPodSuccess PodGCStrategy = "OnPodSuccess"
+ PodGCOnWorkflowCompletion PodGCStrategy = "OnWorkflowCompletion"
+ PodGCOnWorkflowSuccess PodGCStrategy = "OnWorkflowSuccess"
+)
+
 // TemplateGetter is an interface to get templates.
 type TemplateGetter interface {
  GetNamespace() string
@@ -178,6 +189,9 @@ type WorkflowSpec struct {
  // +optional
  SchedulerName string `json:"schedulerName,omitempty"`
 
+ // PodGC describes the strategy to use when to deleting completed pods
+ PodGC *PodGC `json:"podGC,omitempty"`
+
  // PriorityClassName to apply to workflow pods.
  PodPriorityClassName string `json:"podPriorityClassName,omitempty"`
 
@@ -395,6 +409,11 @@ type Artifact struct {
  Optional bool `json:"optional,omitempty"`
 }
 
+// PodGC describes how to delete completed pods as they complete
+type PodGC struct {
+ Strategy PodGCStrategy `json:"strategy,omitempty"`
+}
+
 // ArchiveStrategy describes how to archive files/directory when saving artifacts
 type ArchiveStrategy struct {
  Tar *TarStrategy `json:"tar,omitempty"`
@@ -716,6 +735,11 @@ func (ws *WorkflowStatus) Completed() bool {
  return isCompletedPhase(ws.Phase)
 }
 
+// Successful return whether or not the workflow has succeeded
+func (ws *WorkflowStatus) Successful() bool {
+ return ws.Phase == NodeSucceeded
+}
+
 // Remove returns whether or not the node has completed execution
 func (n NodeStatus) Completed() bool {
  return isCompletedPhase(n.Phase) || n.IsDaemoned() && n.Phase != NodePending

workflow/common/util.go

@@ -19,6 +19,7 @@ import (
  "github.com/valyala/fasttemplate"
  apiv1 "k8s.io/api/core/v1"
  apierr "k8s.io/apimachinery/pkg/api/errors"
+ metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
  "k8s.io/apimachinery/pkg/types"
  "k8s.io/client-go/kubernetes"
  "k8s.io/client-go/rest"
@@ -444,6 +445,21 @@ func addPodMetadata(c kubernetes.Interface, field, podName, namespace, key, valu
  return err
 }
 
+const deleteRetries = 3
+
+// DeletePod deletes a pod. Ignores NotFound error
+func DeletePod(c kubernetes.Interface, podName, namespace string) error {
+ var err error
+ for attempt := 0; attempt < deleteRetries; attempt++ {
+ err = c.CoreV1().Pods(namespace).Delete(podName, &metav1.DeleteOptions{})
+ if err == nil || apierr.IsNotFound(err) {
+ break
+ }
+ time.Sleep(100 * time.Millisecond)
+ }
+ return err
+}
+
 // IsPodTemplate returns whether the template corresponds to a pod
 func IsPodTemplate(tmpl *wfv1.Template) bool {
  if tmpl.Container != nil || tmpl.Script != nil || tmpl.Resource != nil {