concurrency: Add support for queue key

ast.go

@@ -400,6 +400,8 @@ type Concurrency struct {
 	Group *String
 	// CancelInProgress is a flag that shows if canceling this workflow cancels other jobs in progress.
 	CancelInProgress *Bool
+	// Queue is the queue strategy for pending workflow runs. Valid values are "single" (default) and "max".
+	Queue *String
 	// Pos is a position in source.
 	Pos *Pos
 }

parse.go

@@ -820,13 +820,26 @@ func (p *parser) parseConcurrency(pos *Pos, n *yaml.Node) *Concurrency {
 			ret.Group = p.parseString(e.val, false)
 		case "cancel-in-progress":
 			ret.CancelInProgress = p.parseBool(e.val)
+		case "queue":
+			ret.Queue = p.parseString(e.val, false)
+			if ret.Queue != nil && !ret.Queue.ContainsExpression() {
+				switch ret.Queue.Value {
+				case "max", "single":
+					// ok
+				default:
+					p.errorf(e.val, "invalid value %q for \"queue\" in \"concurrency\" section. valid values are \"max\" and \"single\"", ret.Queue.Value)
+				}
+			}
 		default:
-			p.unexpectedKey(e.key, "concurrency", []string{"group", "cancel-in-progress"})
+			p.unexpectedKey(e.key, "concurrency", []string{"cancel-in-progress", "group", "queue"})
 		}
 	}
 	if ret.Group == nil {
 		p.errorAt(pos, "group name is missing in \"concurrency\" section")
 	}
+	if ret.Queue != nil && ret.CancelInProgress != nil && !ret.Queue.ContainsExpression() && ret.Queue.Value == "max" && ret.CancelInProgress.Expression == nil && ret.CancelInProgress.Value {
+		p.errorfAt(ret.Queue.Pos, "\"queue: max\" cannot be combined with \"cancel-in-progress: true\" in \"concurrency\" section")
+	}
 	return ret
 }
 

rule_expression.go

@@ -511,6 +511,7 @@ func (rule *RuleExpression) checkConcurrency(c *Concurrency, workflowKey string)
 	}
 	rule.checkString(c.Group, workflowKey)
 	rule.checkBool(c.CancelInProgress, workflowKey)
+	rule.checkString(c.Queue, workflowKey)
 }
 
 func (rule *RuleExpression) checkDefaults(d *Defaults, workflowKey string) {

testdata/err/case_sensitive_keys.out

@@ -8,9 +8,9 @@ test.yaml:22:9: unexpected key "DESCRIPTION" for outputs at workflow_call event.
 test.yaml:25:5: unexpected key "BRANCHES" for "push" section. expected one of "branches", "branches-ignore", "paths", "paths-ignore", "tags", "tags-ignore", "types", "workflows" [syntax-check]
 test.yaml:28:3: expected "run" key for "defaults" section but got "RUN" [syntax-check]
 test.yaml:30:5: unexpected key "SHELL" for "run" section. expected one of "shell", "working-directory" [syntax-check]
-test.yaml:33:3: unexpected key "GROUP" for "concurrency" section. expected one of "cancel-in-progress", "group" [syntax-check]
+test.yaml:33:3: unexpected key "GROUP" for "concurrency" section. expected one of "cancel-in-progress", "group", "queue" [syntax-check]
 test.yaml:39:5: unexpected key "NAME" for "job" section. expected one of "concurrency", "container", "continue-on-error", "defaults", "env", "environment", "if", "name", "needs", "outputs", "permissions", "runs-on", "secrets", "services", "snapshot", "steps", "strategy", "timeout-minutes", "uses", "with" [syntax-check]
-test.yaml:41:7: unexpected key "GROUP" for "concurrency" section. expected one of "cancel-in-progress", "group" [syntax-check]
+test.yaml:41:7: unexpected key "GROUP" for "concurrency" section. expected one of "cancel-in-progress", "group", "queue" [syntax-check]
 test.yaml:44:7: unexpected key "NAME" for "environment" section. expected one of "deployment", "name", "url" [syntax-check]
 test.yaml:47:7: expected "run" key for "defaults" section but got "RUN" [syntax-check]
 test.yaml:49:9: unexpected key "SHELL" for "run" section. expected one of "shell", "working-directory" [syntax-check]

testdata/err/concurrency_queue.out

@@ -0,0 +1,2 @@
+test.yaml:5:10: invalid value "invalid" for "queue" in "concurrency" section. valid values are "max" and "single" [syntax-check]
+test.yaml:13:14: "queue: max" cannot be combined with "cancel-in-progress: true" in "concurrency" section [syntax-check]

testdata/err/concurrency_queue.yaml

@@ -0,0 +1,15 @@
+on: push
+
+concurrency:
+  group: test
+  queue: invalid
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: job-test
+      cancel-in-progress: true
+      queue: max
+    steps:
+      - run: echo

testdata/err/unexpected_keys.out

@@ -8,7 +8,7 @@ test.yaml:22:9: unexpected key "invalid_key" for outputs at workflow_call event.
 test.yaml:23:5: unexpected key "invalid_key" for "workflow_call" section. expected one of "inputs", "outputs", "secrets" [syntax-check]
 test.yaml:27:5: unexpected key "invalid_key" for "run" section. expected one of "shell", "working-directory" [syntax-check]
 test.yaml:28:3: expected "run" key for "defaults" section but got "invalid_key" [syntax-check]
-test.yaml:32:3: unexpected key "invalid_key" for "concurrency" section. expected one of "cancel-in-progress", "group" [syntax-check]
+test.yaml:32:3: unexpected key "invalid_key" for "concurrency" section. expected one of "cancel-in-progress", "group", "queue" [syntax-check]
 test.yaml:38:7: unexpected key "invalid_key" for "environment" section. expected one of "deployment", "name", "url" [syntax-check]
 test.yaml:40:7: unexpected key "invalid_key" for "strategy" section. expected one of "fail-fast", "matrix", "max-parallel" [syntax-check]
 test.yaml:46:9: unexpected key "invalid_key" for "credentials" section. expected one of "password", "username" [syntax-check]

testdata/ok/concurrency_queue.yaml

@@ -0,0 +1,22 @@
+on: push
+
+concurrency:
+  group: deploy-queue
+  queue: max
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: job-queue
+      cancel-in-progress: false
+      queue: max
+    steps:
+      - run: echo "deploy"
+  test2:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: job-single
+      queue: single
+    steps:
+      - run: echo "single"