feat: allow lastRetry variables in expressions

util/template/expression_template.go

@@ -39,6 +39,17 @@ func expressionReplace(w io.Writer, expression string, env map[string]interface{
 		return w.Write([]byte(fmt.Sprintf("{{%s%s}}", kindExpression, expression)))
 	}
 
+	if (hasVariableInExpression(unmarshalledExpression, "lastRetry.exitCode") && !hasVarInEnv(env, "lastRetry.exitCode") ||
+		hasVariableInExpression(unmarshalledExpression, "lastRetry.status") && !hasVarInEnv(env, "lastRetry.status") ||
+		hasVariableInExpression(unmarshalledExpression, "lastRetry.duration") && !hasVarInEnv(env, "lastRetry.duration") ||
+		hasVariableInExpression(unmarshalledExpression, "lastRetry.message") && !hasVarInEnv(env, "lastRetry.message")) &&
+		allowUnresolved {
+		// This is to make sure expressions which contains `lastRetry.*` don't get resolved to nil
+		// when they don't exist in the env.
+		log.WithError(err).Debug("LastRetry variables are present and unresolved is allowed")
+		return w.Write([]byte(fmt.Sprintf("{{%s%s}}", kindExpression, expression)))
+	}
+
 	// This is to make sure expressions which contains `workflow.status` and `work.failures` don't get resolved to nil
 	// when `workflow.status` and `workflow.failures` don't exist in the env.
 	// See https://github.com/argoproj/argo-workflows/issues/10393, https://github.com/expr-lang/expr/issues/330
@@ -107,6 +118,24 @@ func hasRetries(expression string) bool {
 	return false
 }
 
+func hasVariableInExpression(expression, variable string) bool {
+	if !strings.Contains(expression, variable) {
+		return false
+	}
+	// Even if the expression contains `<variable>`, it could be the case that it represents a string (`"<variable>"`),
+	// not a variable, so we need to parse it and handle filter the string case.
+	tokens, err := lexer.Lex(file.NewSource(expression))
+	if err != nil {
+		return false
+	}
+	for i := 0; i < len(tokens)-2; i++ {
+		if tokens[i].Value+tokens[i+1].Value+tokens[i+2].Value == variable {
+			return true
+		}
+	}
+	return false
+}
+
 // hasWorkflowStatus checks if expression contains `workflow.status`
 func hasWorkflowStatus(expression string) bool {
 	if !strings.Contains(expression, "workflow.status") {

workflow/controller/operator.go

@@ -2128,6 +2128,24 @@ func (woc *wfOperationCtx) executeTemplate(ctx context.Context, nodeName string,
 		// Inject the retryAttempt number
 		localParams[common.LocalVarRetries] = strconv.Itoa(retryNum)
 
+		// Inject lastRetry variables
+		// the first node will not have "lastRetry" variables so they must have default values
+		// for the expression to resolve
+		lastRetryExitCode, lastRetryDuration := "0", "0"
+		var lastRetryStatus, lastRetryMessage string
+		if lastChildNode != nil {
+			if lastChildNode.Outputs != nil && lastChildNode.Outputs.ExitCode != nil {
+				lastRetryExitCode = *lastChildNode.Outputs.ExitCode
+			}
+			lastRetryStatus = string(lastChildNode.Phase)
+			lastRetryDuration = fmt.Sprint(lastChildNode.GetDuration().Seconds())
+			lastRetryMessage = lastChildNode.Message
+		}
+		localParams[common.LocalVarRetriesLastExitCode] = lastRetryExitCode
+		localParams[common.LocalVarRetriesLastDuration] = lastRetryDuration
+		localParams[common.LocalVarRetriesLastStatus] = lastRetryStatus
+		localParams[common.LocalVarRetriesLastMessage] = lastRetryMessage
+
 		processedTmpl, err = common.SubstituteParams(processedTmpl, woc.globalParams, localParams)
 		if errorsutil.IsTransientErr(err) {
 			return node, err

workflow/controller/operator_test.go

@@ -1379,6 +1379,59 @@ func TestRetriesVariableWithGlobalVariableInPodSpecPatch(t *testing.T) {
 	assert.ElementsMatch(t, actual, expected)
 }
 
+var lastretryVariableInPodSpecPatchTemplate = `
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+  name: whalesay
+spec:
+  entrypoint: whalesay
+  templates:
+  - name: whalesay
+    retryStrategy:
+      limit: 10
+    podSpecPatch: |
+      containers:
+        - name: main
+          resources:
+            limits:
+              memory: "{{= (sprig.int(lastRetry.exitCode)==1 ? (sprig.int(retries)+1) : 1)* 100}}Mi"
+    container:
+      image: python:alpine3.6
+      command: ["python", -c]
+      args: ["import sys; sys.exit(1)"]
+`
+
+func TestLastRetryVariableInPodSpecPatch(t *testing.T) {
+	wf := wfv1.MustUnmarshalWorkflow(lastretryVariableInPodSpecPatchTemplate)
+	cancel, controller := newController(wf)
+	defer cancel()
+	ctx := context.Background()
+	iterations := 5
+	var woc *wfOperationCtx
+	for i := 1; i <= iterations; i++ {
+		woc = newWorkflowOperationCtx(wf, controller)
+		if i != 1 {
+			makePodsPhase(ctx, woc, apiv1.PodFailed, withExitCode(1))
+		}
+		woc.operate(ctx)
+		wf = woc.wf
+	}
+
+	pods, err := listPods(woc)
+	assert.NoError(t, err)
+	assert.Len(t, pods.Items, iterations)
+	expected := []string{}
+	actual := []string{}
+	for i := 0; i < iterations; i++ {
+		actual = append(actual, pods.Items[i].Spec.Containers[1].Resources.Limits.Memory().String())
+		expected = append(expected, fmt.Sprintf("%dMi", (i+1)*100))
+	}
+	// expecting memory limit to increase after each retry: "100Mi", "200Mi", "300Mi", "400Mi", "500Mi"
+	// ordering not preserved
+	assert.ElementsMatch(t, actual, expected)
+}
+
 var stepsRetriesVariableTemplate = `
 apiVersion: argoproj.io/v1alpha1
 kind: Workflow