feat(build): Add Build waiting condition

* Add on Build.Status a "Scheduled" condition containing the reason for it's scheduling status

Ref apache#4542

e2e/builder/build_test.go

@@ -32,6 +32,7 @@ import (
 
 	. "github.com/apache/camel-k/v2/e2e/support"
 	v1 "github.com/apache/camel-k/v2/pkg/apis/camel/v1"
+	corev1 "k8s.io/api/core/v1"
 )
 
 type kitOptions struct {
@@ -131,8 +132,10 @@ func TestKitMaxBuildLimit(t *testing.T) {
 				// verify that all builds are successful
 				Eventually(BuildPhase(ns, buildA), TestTimeoutLong).Should(Equal(v1.BuildPhaseSucceeded))
 				Eventually(KitPhase(ns, buildA), TestTimeoutLong).Should(Equal(v1.IntegrationKitPhaseReady))
+
 				Eventually(BuildPhase(ns1, buildB), TestTimeoutLong).Should(Equal(v1.BuildPhaseSucceeded))
 				Eventually(KitPhase(ns1, buildB), TestTimeoutLong).Should(Equal(v1.IntegrationKitPhaseReady))
+
 				Eventually(BuildPhase(ns2, buildC), TestTimeoutLong).Should(Equal(v1.BuildPhaseSucceeded))
 				Eventually(KitPhase(ns2, buildC), TestTimeoutLong).Should(Equal(v1.IntegrationKitPhaseReady))
 			})
@@ -288,6 +291,76 @@ func TestKitMaxBuildLimitDependencyMatchingStrategy(t *testing.T) {
 	})
 }
 
+func TestMaxBuildLimitWaitingBuilds(t *testing.T) {
+	WithNewTestNamespace(t, func(ns string) {
+		createOperator(ns, "8m0s", "--global", "--force")
+
+		pl := Platform(ns)()
+		// set maximum number of running builds and order strategy
+		pl.Spec.Build.MaxRunningBuilds = 1
+		pl.Spec.Build.BuildConfiguration.OrderStrategy = v1.BuildOrderStrategyFIFO
+		if err := TestClient().Update(TestContext, pl); err != nil {
+			t.Error(err)
+			t.FailNow()
+		}
+
+		buildA := "integration-a"
+		buildB := "integration-b"
+		buildC := "integration-c"
+
+		doKitBuildInNamespace(buildA, ns, TestTimeoutShort, kitOptions{
+			operatorID: fmt.Sprintf("camel-k-%s", ns),
+			dependencies: []string{
+				"camel:timer", "camel:log",
+			},
+			traits: []string{
+				"builder.properties=build-property=A",
+			},
+		}, v1.BuildPhaseRunning, v1.IntegrationKitPhaseBuildRunning)
+
+		doKitBuildInNamespace(buildB, ns, TestTimeoutShort, kitOptions{
+			operatorID: fmt.Sprintf("camel-k-%s", ns),
+			dependencies: []string{
+				"camel:cron", "camel:log", "camel:joor",
+			},
+			traits: []string{
+				"builder.properties=build-property=B",
+			},
+		}, v1.BuildPhaseScheduling, v1.IntegrationKitPhaseNone)
+
+		doKitBuildInNamespace(buildC, ns, TestTimeoutShort, kitOptions{
+			operatorID: fmt.Sprintf("camel-k-%s", ns),
+			dependencies: []string{
+				"camel:timer", "camel:log", "camel:joor", "camel:http",
+			},
+			traits: []string{
+				"builder.properties=build-property=C",
+			},
+		}, v1.BuildPhaseScheduling, v1.IntegrationKitPhaseNone)
+
+		// verify that last build is waiting
+		Eventually(BuildConditions(ns, buildC), TestTimeoutMedium).ShouldNot(BeNil())
+		Eventually(
+			BuildCondition(ns, buildC, v1.BuildConditionType(v1.BuildConditionScheduled))().Status,
+			TestTimeoutShort).Should(Equal(corev1.ConditionFalse))
+		Eventually(
+			BuildCondition(ns, buildC, v1.BuildConditionType(v1.BuildConditionScheduled))().Reason,
+			TestTimeoutShort).Should(Equal(v1.BuildConditionWaitingReason))
+
+		// verify that last build is scheduled
+		Eventually(BuildPhase(ns, buildC), TestTimeoutLong).Should(Equal(v1.BuildPhaseSucceeded))
+		Eventually(KitPhase(ns, buildC), TestTimeoutLong).Should(Equal(v1.IntegrationKitPhaseReady))
+
+		Eventually(BuildConditions(ns, buildC), TestTimeoutLong).ShouldNot(BeNil())
+		Eventually(
+			BuildCondition(ns, buildC, v1.BuildConditionType(v1.BuildConditionScheduled))().Status,
+			TestTimeoutShort).Should(Equal(corev1.ConditionTrue))
+		Eventually(
+			BuildCondition(ns, buildC, v1.BuildConditionType(v1.BuildConditionScheduled))().Reason,
+			TestTimeoutShort).Should(Equal(v1.BuildConditionReadyReason))
+	})
+}
+
 func TestKitTimerToLogFullBuild(t *testing.T) {
 	doKitFullBuild(t, "timer-to-log", "8m0s", TestTimeoutLong, kitOptions{
 		dependencies: []string{

e2e/common/traits/builder_test.go

@@ -225,11 +225,12 @@ func TestBuilderTrait(t *testing.T) {
 		// Check containers conditions
 		Eventually(Build(integrationKitNamespace, integrationKitName), TestTimeoutLong).ShouldNot(BeNil())
 		Eventually(BuildConditions(integrationKitNamespace, integrationKitName), TestTimeoutLong).ShouldNot(BeNil())
+		Eventually(BuildCondition(integrationKitNamespace, integrationKitName, v1.BuildConditionType("Container custom1 succeeded")), TestTimeoutMedium).ShouldNot(BeNil())
 		Eventually(
-			Build(integrationKitNamespace, integrationKitName)().Status.GetCondition(v1.BuildConditionType("Container custom1 succeeded")).Status,
+			BuildCondition(integrationKitNamespace, integrationKitName, v1.BuildConditionType("Container custom1 succeeded"))().Status,
 			TestTimeoutShort).Should(Equal(corev1.ConditionFalse))
 		Eventually(
-			Build(integrationKitNamespace, integrationKitName)().Status.GetCondition(v1.BuildConditionType("Container custom1 succeeded")).Message,
+			BuildCondition(integrationKitNamespace, integrationKitName, v1.BuildConditionType("Container custom1 succeeded"))().Message,
 			TestTimeoutShort).Should(ContainSubstring("No such file or directory"))
 
 		Expect(Kamel("delete", "--all", "-n", ns).Execute()).To(Succeed())

e2e/support/test_support.go

@@ -1872,6 +1872,16 @@ func BuildConditions(ns, name string) func() []v1.BuildCondition {
 	}
 }
 
+func BuildCondition(ns string, name string, conditionType v1.BuildConditionType) func() *v1.BuildCondition {
+	return func() *v1.BuildCondition {
+		build := Build(ns, name)()
+		if build != nil && &build.Status != nil && build.Status.Conditions != nil {
+			return build.Status.GetCondition(conditionType)
+		}
+		return &v1.BuildCondition{}
+	}
+}
+
 func BuildFailureRecovery(ns, name string) func() int {
 	return func() int {
 		build := Build(ns, name)()

pkg/apis/camel/v1/build_types.go

@@ -256,6 +256,14 @@ const (
 	BuildPhaseInterrupted = "Interrupted"
 	// BuildPhaseError -- .
 	BuildPhaseError BuildPhase = "Error"
+
+	// BuildConditionScheduled --.
+	BuildConditionScheduled BuildConditionType = "Scheduled"
+
+	// BuildConditionReadyReason --.
+	BuildConditionReadyReason string = "Ready"
+	// BuildConditionWaitingReason --.
+	BuildConditionWaitingReason string = "Waiting"
 )
 
 // +genclient

pkg/controller/build/build_monitor.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"sync"
 
+	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/selection"
 	"k8s.io/apimachinery/pkg/types"
@@ -31,14 +32,17 @@ import (
 	"github.com/apache/camel-k/v2/pkg/util/kubernetes"
 )
 
+const enqueuedMsg = "%s - the build (%s) gets enqueued"
+
 var runningBuilds sync.Map
 
 type Monitor struct {
 	maxRunningBuilds   int32
 	buildOrderStrategy v1.BuildOrderStrategy
 }
 
-func (bm *Monitor) canSchedule(ctx context.Context, c ctrl.Reader, build *v1.Build) (bool, error) {
+func (bm *Monitor) canSchedule(ctx context.Context, c ctrl.Reader, build *v1.Build) (bool, *v1.BuildCondition, error) {
+
 	var runningBuildsTotal int32
 	runningBuilds.Range(func(_, v interface{}) bool {
 		runningBuildsTotal++
@@ -54,24 +58,27 @@ func (bm *Monitor) canSchedule(ctx context.Context, c ctrl.Reader, build *v1.Bui
 	}
 
 	if runningBuildsTotal >= bm.maxRunningBuilds {
+		reason := fmt.Sprintf(
+			"Maximum number of running builds (%d) exceeded",
+			runningBuildsTotal,
+		)
 		Log.WithValues("request-namespace", requestNamespace, "request-name", requestName, "max-running-builds-limit", runningBuildsTotal).
-			ForBuild(build).Infof("Maximum number of running builds (%d) exceeded - the build (%s) gets enqueued", runningBuildsTotal, build.Name)
-
+			ForBuild(build).Infof(enqueuedMsg, reason, build.Name)
 		// max number of running builds limit exceeded
-		return false, nil
+		return false, scheduledWaitingBuildcondition(build.Name, reason), nil
 	}
 
 	layout := build.Labels[v1.IntegrationKitLayoutLabel]
 
 	// Native builds can be run in parallel, as incremental images is not applicable.
 	if layout == v1.IntegrationKitLayoutNativeSources {
-		return true, nil
+		return true, scheduledReadyBuildcondition(build.Name), nil
 	}
 
 	// We assume incremental images is only applicable across images whose layout is identical
 	withCompatibleLayout, err := labels.NewRequirement(v1.IntegrationKitLayoutLabel, selection.Equals, []string{layout})
 	if err != nil {
-		return false, err
+		return false, nil, err
 	}
 
 	builds := &v1.BuildList{}
@@ -83,11 +90,12 @@ func (bm *Monitor) canSchedule(ctx context.Context, c ctrl.Reader, build *v1.Bui
 			Selector: labels.NewSelector().Add(*withCompatibleLayout),
 		})
 	if err != nil {
-		return false, err
+		return false, nil, err
 	}
 
 	var reason string
 	allowed := true
+	condition := scheduledReadyBuildcondition(build.Name)
 	switch bm.buildOrderStrategy {
 	case v1.BuildOrderStrategyFIFO:
 		// Check on builds that have been created before the current build and grant precedence if any.
@@ -116,10 +124,11 @@ func (bm *Monitor) canSchedule(ctx context.Context, c ctrl.Reader, build *v1.Bui
 
 	if !allowed {
 		Log.WithValues("request-namespace", requestNamespace, "request-name", requestName, "order-strategy", bm.buildOrderStrategy).
-			ForBuild(build).Infof("%s - the build (%s) gets enqueued", reason, build.Name)
+			ForBuild(build).Infof(enqueuedMsg, reason, build.Name)
+		condition = scheduledWaitingBuildcondition(build.Name, reason)
 	}
 
-	return allowed, nil
+	return allowed, condition, nil
 }
 
 func monitorRunningBuild(build *v1.Build) {
@@ -129,3 +138,27 @@ func monitorRunningBuild(build *v1.Build) {
 func monitorFinishedBuild(build *v1.Build) {
 	runningBuilds.Delete(types.NamespacedName{Namespace: build.Namespace, Name: build.Name}.String())
 }
+
+func scheduledReadyBuildcondition(buildName string) *v1.BuildCondition {
+	return scheduledBuildcondition(corev1.ConditionTrue, v1.BuildConditionReadyReason, fmt.Sprintf(
+		"the build (%s) is scheduled",
+		buildName,
+	))
+}
+
+func scheduledWaitingBuildcondition(buildName string, reason string) *v1.BuildCondition {
+	return scheduledBuildcondition(corev1.ConditionFalse, v1.BuildConditionWaitingReason, fmt.Sprintf(
+		enqueuedMsg,
+		reason,
+		buildName,
+	))
+}
+
+func scheduledBuildcondition(status corev1.ConditionStatus, reason string, msg string) *v1.BuildCondition {
+	return &v1.BuildCondition{
+		Type:    v1.BuildConditionScheduled,
+		Status:  status,
+		Reason:  reason,
+		Message: msg,
+	}
+}