servicedisco: ensure service uniqueness in job validation

.changelog/13869.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+servicedisco: Fixed a bug where non-unique services would escape job validation
+```

nomad/structs/structs.go

@@ -25,25 +25,25 @@ import (
 	"time"
 
 	jwt "github.com/golang-jwt/jwt/v4"
-	"github.com/hashicorp/nomad/helper/escapingfs"
-	"golang.org/x/crypto/blake2b"
-
 	"github.com/hashicorp/cronexpr"
 	"github.com/hashicorp/go-msgpack/codec"
 	"github.com/hashicorp/go-multierror"
+	"github.com/hashicorp/go-set"
 	"github.com/hashicorp/go-version"
 	"github.com/hashicorp/nomad/acl"
 	"github.com/hashicorp/nomad/command/agent/host"
 	"github.com/hashicorp/nomad/command/agent/pprof"
 	"github.com/hashicorp/nomad/helper"
 	"github.com/hashicorp/nomad/helper/args"
 	"github.com/hashicorp/nomad/helper/constraints/semver"
+	"github.com/hashicorp/nomad/helper/escapingfs"
 	"github.com/hashicorp/nomad/helper/uuid"
 	"github.com/hashicorp/nomad/lib/cpuset"
 	"github.com/hashicorp/nomad/lib/kheap"
 	psstructs "github.com/hashicorp/nomad/plugins/shared/structs"
 	"github.com/miekg/dns"
 	"github.com/mitchellh/copystructure"
+	"golang.org/x/crypto/blake2b"
 )
 
 var (
@@ -6522,6 +6522,7 @@ func (tg *TaskGroup) Validate(j *Job) error {
 			mErr.Errors = append(mErr.Errors, outer)
 		}
 	}
+
 	return mErr.ErrorOrNil()
 }
 
@@ -6623,41 +6624,69 @@ func (tg *TaskGroup) validateNetworks() error {
 // group service checks that refer to tasks only refer to tasks that exist.
 func (tg *TaskGroup) validateServices() error {
 	var mErr multierror.Error
-	knownTasks := make(map[string]struct{})
 
-	// Track the providers used for this task group. Currently, Nomad only
+	// Accumulate task names in this group
+	taskSet := set.New[string](len(tg.Tasks))
+
+	// each service in a group must be unique (i.e. used in MakeAllocServiceID)
+	type unique struct {
+		name string
+		task string
+		port string
+	}
+
+	// Accumulate service IDs in this group
+	idSet := set.New[unique](0)
+
+	// Accumulate IDs that are duplicates
+	idDuplicateSet := set.New[unique](0)
+
+	// Accumulate the providers used for this task group. Currently, Nomad only
 	// allows the use of a single service provider within a task group.
-	configuredProviders := make(map[string]struct{})
+	providerSet := set.New[string](1)
 
 	// Create a map of known tasks and their services so we can compare
 	// vs the group-level services and checks
 	for _, task := range tg.Tasks {
-		knownTasks[task.Name] = struct{}{}
-		if task.Services == nil {
+		taskSet.Insert(task.Name)
+
+		if len(task.Services) == 0 {
 			continue
 		}
+
 		for _, service := range task.Services {
+
+			// Ensure no task-level checks specify a task
 			for _, check := range service.Checks {
 				if check.TaskName != "" {
 					mErr.Errors = append(mErr.Errors, fmt.Errorf("Check %s is invalid: only task group service checks can be assigned tasks", check.Name))
 				}
 			}
 
-			// Add the service provider to the tracking, if it has not already
-			// been seen.
-			if _, ok := configuredProviders[service.Provider]; !ok {
-				configuredProviders[service.Provider] = struct{}{}
+			// Track that we have seen this service id
+			id := unique{service.Name, task.Name, service.PortLabel}
+			if !idSet.Insert(id) {
+				// accumulate duplicates for a single error later on
+				idDuplicateSet.Insert(id)
 			}
+
+			// Track that we have seen this service provider
+			providerSet.Insert(service.Provider)
 		}
 	}
+
 	for i, service := range tg.Services {
 
-		// Add the service provider to the tracking, if it has not already been
-		// seen.
-		if _, ok := configuredProviders[service.Provider]; !ok {
-			configuredProviders[service.Provider] = struct{}{}
+		// Track that we have seen this service id
+		id := unique{service.Name, "group", service.PortLabel}
+		if !idSet.Insert(id) {
+			// accumulate duplicates for a single error later on
+			idDuplicateSet.Insert(id)
 		}
 
+		// Track that we have seen this service provider
+		providerSet.Insert(service.Provider)
+
 		if err := service.Validate(); err != nil {
 			outer := fmt.Errorf("Service[%d] %s validation failed: %s", i, service.Name, err)
 			mErr.Errors = append(mErr.Errors, outer)
@@ -6679,18 +6708,37 @@ func (tg *TaskGroup) validateServices() error {
 				if check.AddressMode == AddressModeDriver {
 					mErr.Errors = append(mErr.Errors, fmt.Errorf("Check %q invalid: cannot use address_mode=\"driver\", only checks defined in a \"task\" service block can use this mode", service.Name))
 				}
-				if _, ok := knownTasks[check.TaskName]; !ok {
+				if !taskSet.Contains(check.TaskName) {
 					mErr.Errors = append(mErr.Errors,
 						fmt.Errorf("Check %s invalid: refers to non-existent task %s", check.Name, check.TaskName))
 				}
 			}
 		}
 	}
 
+	// Produce an error of any services which are not unique enough in the group
+	// i.e. have same <task, name, port>
+	if idDuplicateSet.Size() > 0 {
+		mErr.Errors = append(mErr.Errors,
+			fmt.Errorf(
+				"Services are not unique: %s",
+				idDuplicateSet.String(
+					func(u unique) string {
+						s := u.task + "->" + u.name
+						if u.port != "" {
+							s += ":" + u.port
+						}
+						return s
+					},
+				),
+			),
+		)
+	}
+
 	// The initial feature release of native service discovery only allows for
 	// a single service provider to be used across all services in a task
 	// group.
-	if len(configuredProviders) > 1 {
+	if providerSet.Size() > 1 {
 		mErr.Errors = append(mErr.Errors,
 			errors.New("Multiple service providers used: task group services must use the same provider"))
 	}