api: remove `mapstructure` tags from`Port` struct (#12916)

This PR solves a defect in the deserialization of api.Port structs when returning structs from theEventStream.

Previously, the api.Port struct's fields were decorated with both mapstructure and hcl tags to support the network.port stanza's use of the keyword static when posting a static port value. This works fine when posting a job and when retrieving any struct that has an embedded api.Port instance as long as the value is deserialized using JSON decoding. The EventStream, however, uses mapstructure to decode event payloads in the api package. mapstructure expects an underlying field named static which does not exist. The result was that the Port.Value field would always be set to 0.

Upon further inspection, a few things became apparent.

The struct already has hcl tags that support the indirection during job submission.
Serialization/deserialization with both the json and hcl packages produce the desired result.
The use of of the mapstructure tags provided no value as the Port struct contains only fields with primitive types.
This PR:

Removes the mapstructure tags from the api.Port structs
Updates the job parsing logic to use hcl instead of mapstructure when decoding Port instances.
Closes #11044

Co-authored-by: DerekStrickland <dstrickland@hashicorp.com>
Co-authored-by: Piotr Kazmierczak <470696+pkazmierczak@users.noreply.github.com>

.changelog/12916.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+event_stream: fixed a bug where dynamic port values would fail to serialize in the event stream
+```

api/resources.go

@@ -98,9 +98,9 @@ func (r *Resources) Merge(other *Resources) {
 
 type Port struct {
 	Label       string `hcl:",label"`
-	Value       int    `mapstructure:"static" hcl:"static,optional"`
-	To          int    `mapstructure:"to" hcl:"to,optional"`
-	HostNetwork string `mapstructure:"host_network" hcl:"host_network,optional"`
+	Value       int    `hcl:"static,optional"`
+	To          int    `hcl:"to,optional"`
+	HostNetwork string `hcl:"host_network,optional"`
 }
 
 type DNSConfig struct {

client/client_test.go

@@ -727,6 +727,7 @@ func TestClient_Init(t *testing.T) {
 	ci.Parallel(t)
 
 	dir := t.TempDir()
+
 	allocDir := filepath.Join(dir, "alloc")
 
 	config := config.DefaultConfig()

command/agent/event_endpoint_test.go

@@ -10,8 +10,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/nomad/api"
 	"github.com/hashicorp/nomad/ci"
 	"github.com/hashicorp/nomad/helper/uuid"
+	"github.com/hashicorp/nomad/nomad/mock"
 	"github.com/hashicorp/nomad/nomad/structs"
 	"github.com/hashicorp/nomad/testutil"
 	"github.com/stretchr/testify/assert"
@@ -202,3 +204,103 @@ func TestEventStream_QueryParse(t *testing.T) {
 		})
 	}
 }
+
+func TestHTTP_Alloc_Port_Response(t *testing.T) {
+	ci.Parallel(t)
+
+	httpTest(t, nil, func(srv *TestAgent) {
+		client := srv.Client()
+		defer srv.Shutdown()
+		defer client.Close()
+
+		testutil.WaitForLeader(t, srv.Agent.RPC)
+		testutil.WaitForClient(t, srv.Agent.Client().RPC, srv.Agent.Client().NodeID(), srv.Agent.Client().Region())
+
+		job := MockRunnableJob()
+
+		resp, _, err := client.Jobs().Register(job, nil)
+		require.NoError(t, err)
+		require.NotEmpty(t, resp.EvalID)
+
+		alloc := mock.Alloc()
+		alloc.Job = ApiJobToStructJob(job)
+		alloc.JobID = *job.ID
+		alloc.NodeID = srv.client.NodeID()
+
+		require.Nil(t, srv.server.State().UpsertJobSummary(101, mock.JobSummary(alloc.JobID)))
+		require.Nil(t, srv.server.State().UpsertAllocs(structs.MsgTypeTestSetup, 102, []*structs.Allocation{alloc}))
+
+		running := false
+		testutil.WaitForResult(func() (bool, error) {
+			upsertResult, stateErr := srv.server.State().AllocByID(nil, alloc.ID)
+			if stateErr != nil {
+				return false, stateErr
+			}
+			if upsertResult.ClientStatus == structs.AllocClientStatusRunning {
+				running = true
+				return true, nil
+			}
+			return false, nil
+		}, func(err error) {
+			require.NoError(t, err, "allocation query failed")
+		})
+
+		require.True(t, running)
+
+		topics := map[api.Topic][]string{
+			api.TopicAllocation: {*job.ID},
+		}
+
+		ctx, cancel := context.WithCancel(context.Background())
+		defer cancel()
+
+		events := client.EventStream()
+		streamCh, err := events.Stream(ctx, topics, 1, nil)
+		require.NoError(t, err)
+
+		var allocEvents []api.Event
+		// gather job alloc events
+		go func() {
+			for {
+				select {
+				case event, ok := <-streamCh:
+					if !ok {
+						return
+					}
+					if event.IsHeartbeat() {
+						continue
+					}
+					allocEvents = append(allocEvents, event.Events...)
+				case <-time.After(10 * time.Second):
+					require.Fail(t, "failed waiting for event stream event")
+				}
+			}
+		}()
+
+		var networkResource *api.NetworkResource
+		testutil.WaitForResult(func() (bool, error) {
+			for _, e := range allocEvents {
+				if e.Type == structs.TypeAllocationUpdated {
+					eventAlloc, err := e.Allocation()
+					if err != nil {
+						return false, err
+					}
+					if len(eventAlloc.AllocatedResources.Tasks["web"].Networks) == 0 {
+						return false, nil
+					}
+					networkResource = eventAlloc.AllocatedResources.Tasks["web"].Networks[0]
+					if networkResource.ReservedPorts[0].Value == 5000 {
+						return true, nil
+					}
+				}
+			}
+			return false, nil
+		}, func(e error) {
+			require.NoError(t, err)
+		})
+
+		require.NotNil(t, networkResource)
+		require.Equal(t, 5000, networkResource.ReservedPorts[0].Value)
+		require.NotEqual(t, 0, networkResource.DynamicPorts[0].Value)
+	})
+}

command/agent/testingutils_test.go

@@ -104,3 +104,21 @@ func MockRegionalJob() *api.Job {
 	j.Region = pointer.Of("north-america")
 	return j
 }
+
+// MockRunnableJob returns a mock job that has a configuration that allows it to be
+// placed on a TestAgent.
+func MockRunnableJob() *api.Job {
+	job := MockJob()
+
+	// Configure job so it can be run on a TestAgent
+	job.Constraints = nil
+	job.TaskGroups[0].Constraints = nil
+	job.TaskGroups[0].Count = pointer.Of(1)
+	job.TaskGroups[0].Tasks[0].Driver = "mock_driver"
+	job.TaskGroups[0].Tasks[0].Services = nil
+	job.TaskGroups[0].Tasks[0].Config = map[string]interface{}{
+		"run_for": "10s",
+	}
+
+	return job
+}

e2e/events/input/deploy.nomad

@@ -16,6 +16,12 @@ job "deployment_auto.nomad" {
       min_healthy_time = "1s"
     }
 
+    network {
+      port "db" {
+        static = 9000
+      }
+    }
+
     task "one" {
       driver = "raw_exec"
 
@@ -24,10 +30,12 @@ job "deployment_auto.nomad" {
       }
 
       config {
-        command = "/bin/sleep"
+        image   = "busybox:1"
+        command = "nc"
 
         # change args to update the job, the only changes
-        args = ["1000000"]
+        args  = ["-ll", "-p", "1234", "-e", "/bin/cat"]
+        ports = ["db"]
       }
 
       resources {

e2e/events/input/initial.nomad

@@ -15,17 +15,25 @@ job "deployment_auto.nomad" {
       canary       = 2
     }
 
+    network {
+      port "db" {
+        static = 9000
+      }
+    }
+
     task "one" {
-      driver = "raw_exec"
+      driver = "docker"
 
       env {
         version = "0"
       }
       config {
-        command = "/bin/sleep"
+        image   = "busybox:1"
+        command = "nc"
 
         # change args to update the job, the only changes
-        args = ["1000000"]
+        args  = ["-ll", "-p", "1234", "-e", "/bin/cat"]
+        ports = ["db"]
       }
 
       resources {

jobspec/parse_network.go

@@ -93,14 +93,12 @@ func parsePorts(networkObj *ast.ObjectList, nw *api.NetworkResource) error {
 		if knownPortLabels[l] {
 			return fmt.Errorf("found a port label collision: %s", label)
 		}
-		var p map[string]interface{}
+
 		var res api.Port
-		if err := hcl.DecodeObject(&p, port.Val); err != nil {
-			return err
-		}
-		if err := mapstructure.WeakDecode(p, &res); err != nil {
+		if err := hcl.DecodeObject(&res, port.Val); err != nil {
 			return err
 		}
+
 		res.Label = label
 		if res.Value > 0 {
 			nw.ReservedPorts = append(nw.ReservedPorts, res)

jobspec/parse_test.go

@@ -1924,3 +1924,28 @@ func TestIncorrectKey(t *testing.T) {
 		t.Fatalf("Expected key error; got %v", err)
 	}
 }
+
+// TestPortParsing validates that the removal of the mapstructure tags on the
+// Port struct don't cause issues with HCL 1 parsing.
+//
+// TODO: in the future, see if we need `mapstructure` tags on any of the API
+func TestPortParsing(t *testing.T) {
+	ci.Parallel(t)
+
+	var err error
+	var path string
+	var job *api.Job
+
+	path, err = filepath.Abs(filepath.Join("./test-fixtures", "parse-ports.hcl"))
+	require.NoError(t, err, "Can't get absolute path for file: parse-ports.hcl")
+
+	job, err = ParseFile(path)
+	require.NoError(t, err, "cannot parse job")
+	require.NotNil(t, job)
+	require.Len(t, job.TaskGroups, 1)
+	require.Len(t, job.TaskGroups[0].Networks, 1)
+	require.Len(t, job.TaskGroups[0].Networks[0].ReservedPorts, 1)
+	require.Len(t, job.TaskGroups[0].Networks[0].DynamicPorts, 1)
+	require.Equal(t, 9000, job.TaskGroups[0].Networks[0].ReservedPorts[0].Value)
+	require.Equal(t, 0, job.TaskGroups[0].Networks[0].DynamicPorts[0].Value)
+}

jobspec/test-fixtures/parse-ports.hcl

@@ -0,0 +1,11 @@
+job "parse-ports" {
+  group "group" {
+    network {
+      port "static" {
+        static = 9000
+      }
+
+      port "dynamic" {}
+    }
+  }
+}