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aaronlehmannaaronlehmann
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Merge pull request #2266 from mion00/feature/template-node-hostname
Add support for templating Node.Hostname in docker executor
2 parents e15198c + 69602b4 commit 9cbc2cc

12 files changed

+220
-49
lines changed

‎agent/exec/dockerapi/adapter.go

+2-2
Original file line numberDiff line numberDiff line change
@@ -29,8 +29,8 @@ type containerAdapter struct {
2929
secrets exec.SecretGetter
3030
}
3131

32-
func newContainerAdapter(client engineapi.APIClient, task *api.Task, secrets exec.SecretGetter) (*containerAdapter, error) {
33-
ctnr, err := newContainerConfig(task)
32+
func newContainerAdapter(client engineapi.APIClient, nodeDescription *api.NodeDescription, task *api.Task, secrets exec.SecretGetter) (*containerAdapter, error) {
33+
ctnr, err := newContainerConfig(nodeDescription, task)
3434
if err != nil {
3535
return nil, err
3636
}

‎agent/exec/dockerapi/container.go

+4-4
Original file line numberDiff line numberDiff line change
@@ -42,12 +42,12 @@ type containerConfig struct {
4242

4343
// newContainerConfig returns a validated container config. No methods should
4444
// return an error if this function returns without error.
45-
func newContainerConfig(t *api.Task) (*containerConfig, error) {
45+
func newContainerConfig(n *api.NodeDescription, t *api.Task) (*containerConfig, error) {
4646
var c containerConfig
47-
return &c, c.setTask(t)
47+
return &c, c.setTask(n, t)
4848
}
4949

50-
func (c *containerConfig) setTask(t *api.Task) error {
50+
func (c *containerConfig) setTask(n *api.NodeDescription, t *api.Task) error {
5151
container := t.Spec.GetContainer()
5252
if container == nil {
5353
return exec.ErrRuntimeUnsupported
@@ -64,7 +64,7 @@ func (c *containerConfig) setTask(t *api.Task) error {
6464
}
6565

6666
c.task = t
67-
preparedSpec, err := template.ExpandContainerSpec(t)
67+
preparedSpec, err := template.ExpandContainerSpec(n, t)
6868
if err != nil {
6969
return err
7070
}

‎agent/exec/dockerapi/controller.go

+2-2
Original file line numberDiff line numberDiff line change
@@ -41,8 +41,8 @@ type controller struct {
4141
var _ exec.Controller = &controller{}
4242

4343
// newController returns a docker exec controller for the provided task.
44-
func newController(client engineapi.APIClient, task *api.Task, secrets exec.SecretGetter) (exec.Controller, error) {
45-
adapter, err := newContainerAdapter(client, task, secrets)
44+
func newController(client engineapi.APIClient, nodeDescription *api.NodeDescription, task *api.Task, secrets exec.SecretGetter) (exec.Controller, error) {
45+
adapter, err := newContainerAdapter(client, nodeDescription, task, secrets)
4646
if err != nil {
4747
return nil, err
4848
}

‎agent/exec/dockerapi/controller_integration_test.go

+1-1
Original file line numberDiff line numberDiff line change
@@ -80,7 +80,7 @@ func TestControllerFlowIntegration(t *testing.T) {
8080
return nil
8181
})
8282

83-
ctlr, err := newController(client, task, nil)
83+
ctlr, err := newController(client, nil, task, nil)
8484
assert.NoError(t, err)
8585
assert.NotNil(t, ctlr)
8686
assert.NoError(t, ctlr.Prepare(ctx))

‎agent/exec/dockerapi/controller_test.go

+10-2
Original file line numberDiff line numberDiff line change
@@ -411,11 +411,19 @@ func TestControllerRemove(t *testing.T) {
411411
}
412412

413413
func genTestControllerEnv(t *testing.T, task *api.Task) (context.Context, *StubAPIClient, exec.Controller, *containerConfig, func()) {
414+
testNodeDescription := &api.NodeDescription{
415+
Hostname: "testHostname",
416+
Platform: &api.Platform{
417+
OS: "linux",
418+
Architecture: "x86_64",
419+
},
420+
}
421+
414422
client := NewStubAPIClient()
415-
ctlr, err := newController(client, task, nil)
423+
ctlr, err := newController(client, testNodeDescription, task, nil)
416424
assert.NoError(t, err)
417425

418-
config, err := newContainerConfig(task)
426+
config, err := newContainerConfig(testNodeDescription, task)
419427
assert.NoError(t, err)
420428
assert.NotNil(t, config)
421429

‎agent/exec/dockerapi/executor.go

+15-2
Original file line numberDiff line numberDiff line change
@@ -11,21 +11,25 @@ import (
1111
"github.com/docker/swarmkit/api"
1212
"github.com/docker/swarmkit/log"
1313
"golang.org/x/net/context"
14+
"sync"
1415
)
1516

1617
type executor struct {
1718
client engineapi.APIClient
1819
secrets exec.SecretsManager
1920
genericResources []*api.GenericResource
21+
mutex sync.Mutex // This mutex protects the following node field
22+
node *api.NodeDescription
2023
}
2124

2225
// NewExecutor returns an executor from the docker client.
2326
func NewExecutor(client engineapi.APIClient, genericResources []*api.GenericResource) exec.Executor {
24-
return &executor{
27+
var executor = &executor{
2528
client: client,
2629
secrets: secrets.NewManager(),
2730
genericResources: genericResources,
2831
}
32+
return executor
2933
}
3034

3135
// Describe returns the underlying node description from the docker client.
@@ -111,6 +115,11 @@ func (e *executor) Describe(ctx context.Context) (*api.NodeDescription, error) {
111115
},
112116
}
113117

118+
// Save the node information in the executor field
119+
e.mutex.Lock()
120+
e.node = description
121+
e.mutex.Unlock()
122+
114123
return description, nil
115124
}
116125

@@ -120,7 +129,11 @@ func (e *executor) Configure(ctx context.Context, node *api.Node) error {
120129

121130
// Controller returns a docker container controller.
122131
func (e *executor) Controller(t *api.Task) (exec.Controller, error) {
123-
ctlr, err := newController(e.client, t, secrets.Restrict(e.secrets, t))
132+
// Get the node description from the executor field
133+
e.mutex.Lock()
134+
nodeDescription := e.node
135+
e.mutex.Unlock()
136+
ctlr, err := newController(e.client, nodeDescription, t, secrets.Restrict(e.secrets, t))
124137
if err != nil {
125138
return nil, err
126139
}

‎manager/controlapi/service.go

+7-1
Original file line numberDiff line numberDiff line change
@@ -128,7 +128,13 @@ func validateContainerSpec(taskSpec api.TaskSpec) error {
128128
// Building a empty/dummy Task to validate the templating and
129129
// the resulting container spec as well. This is a *best effort*
130130
// validation.
131-
container, err := template.ExpandContainerSpec(&api.Task{
131+
container, err := template.ExpandContainerSpec(&api.NodeDescription{
132+
Hostname: "nodeHostname",
133+
Platform: &api.Platform{
134+
OS: "os",
135+
Architecture: "architecture",
136+
},
137+
}, &api.Task{
132138
Spec: taskSpec,
133139
ServiceID: "serviceid",
134140
Slot: 1,

‎template/context.go

+25-7
Original file line numberDiff line numberDiff line change
@@ -14,6 +14,12 @@ import (
1414
"github.com/pkg/errors"
1515
)
1616

17+
// Platform holds information about the underlying platform of the node
18+
type Platform struct {
19+
Architecture string
20+
OS string
21+
}
22+
1723
// Context defines the strict set of values that can be injected into a
1824
// template expression in SwarmKit data structure.
1925
// NOTE: Be very careful adding any fields to this structure with types
@@ -27,7 +33,9 @@ type Context struct {
2733
}
2834

2935
Node struct {
30-
ID string
36+
ID string
37+
Hostname string
38+
Platform Platform
3139
}
3240

3341
Task struct {
@@ -41,16 +49,25 @@ type Context struct {
4149
}
4250
}
4351

44-
// NewContextFromTask returns a new template context from the data available in
45-
// task. The provided context can then be used to populate runtime values in a
52+
// NewContext returns a new template context from the data available in the
53+
// task and the node where it is scheduled to run.
54+
// The provided context can then be used to populate runtime values in a
4655
// ContainerSpec.
47-
func NewContextFromTask(t *api.Task) (ctx Context) {
56+
func NewContext(n *api.NodeDescription, t *api.Task) (ctx Context) {
4857
ctx.Service.ID = t.ServiceID
4958
ctx.Service.Name = t.ServiceAnnotations.Name
5059
ctx.Service.Labels = t.ServiceAnnotations.Labels
5160

5261
ctx.Node.ID = t.NodeID
5362

63+
// Add node information to context only if we have them available
64+
if n != nil {
65+
ctx.Node.Hostname = n.Hostname
66+
ctx.Node.Platform = Platform{
67+
Architecture: n.Platform.Architecture,
68+
OS: n.Platform.OS,
69+
}
70+
}
5471
ctx.Task.ID = t.ID
5572
ctx.Task.Name = naming.Task(t)
5673

@@ -157,12 +174,13 @@ func (ctx PayloadContext) envGetter(variable string) (string, error) {
157174
}
158175

159176
// NewPayloadContextFromTask returns a new template context from the data
160-
// available in the task. This context also provides access to the configs
177+
// available in the task and the node where it is scheduled to run.
178+
// This context also provides access to the configs
161179
// and secrets that the task has access to. The provided context can then
162180
// be used to populate runtime values in a templated config or secret.
163-
func NewPayloadContextFromTask(t *api.Task, dependencies exec.DependencyGetter) (ctx PayloadContext) {
181+
func NewPayloadContextFromTask(node *api.NodeDescription, t *api.Task, dependencies exec.DependencyGetter) (ctx PayloadContext) {
164182
return PayloadContext{
165-
Context: NewContextFromTask(t),
183+
Context: NewContext(node, t),
166184
t: t,
167185
restrictedSecrets: secrets.Restrict(dependencies.Secrets(), t),
168186
restrictedConfigs: configs.Restrict(dependencies.Configs(), t),

‎template/context_test.go

+69-6
Original file line numberDiff line numberDiff line change
@@ -10,11 +10,12 @@ import (
1010

1111
func TestTemplateContext(t *testing.T) {
1212
for _, testcase := range []struct {
13-
Test string
14-
Task *api.Task
15-
Context Context
16-
Expected *api.ContainerSpec
17-
Err error
13+
Test string
14+
Task *api.Task
15+
Context Context
16+
Expected *api.ContainerSpec
17+
Err error
18+
NodeDescription *api.NodeDescription
1819
}{
1920
{
2021
Test: "Identity",
@@ -35,6 +36,8 @@ func TestTemplateContext(t *testing.T) {
3536
},
3637
}
3738
}),
39+
NodeDescription: modifyNode(func(n *api.NodeDescription) {
40+
}),
3841
Expected: &api.ContainerSpec{
3942
Env: []string{
4043
"NOTOUCH=dont",
@@ -70,6 +73,8 @@ func TestTemplateContext(t *testing.T) {
7073
},
7174
}
7275
}),
76+
NodeDescription: modifyNode(func(n *api.NodeDescription) {
77+
}),
7378
Expected: &api.ContainerSpec{
7479
Labels: map[string]string{
7580
"ContainerLabel": "should-NOT-end-up-as-task",
@@ -106,6 +111,8 @@ func TestTemplateContext(t *testing.T) {
106111
},
107112
}
108113
}),
114+
NodeDescription: modifyNode(func(n *api.NodeDescription) {
115+
}),
109116
Expected: &api.ContainerSpec{
110117
Mounts: []api.Mount{
111118
{
@@ -130,13 +137,53 @@ func TestTemplateContext(t *testing.T) {
130137
},
131138
}
132139
}),
140+
NodeDescription: modifyNode(func(n *api.NodeDescription) {
141+
}),
133142
Expected: &api.ContainerSpec{
134143
Hostname: "myhost-10",
135144
},
136145
},
146+
{
147+
Test: "Node hostname",
148+
Task: modifyTask(func(t *api.Task) {
149+
t.Spec = api.TaskSpec{
150+
Runtime: &api.TaskSpec_Container{
151+
Container: &api.ContainerSpec{
152+
Hostname: "myservice-{{.Node.Hostname}}",
153+
},
154+
},
155+
}
156+
}),
157+
NodeDescription: modifyNode(func(n *api.NodeDescription) {
158+
n.Hostname = "mynode"
159+
}),
160+
Expected: &api.ContainerSpec{
161+
Hostname: "myservice-mynode",
162+
},
163+
},
164+
{
165+
Test: "Node architecture",
166+
Task: modifyTask(func(t *api.Task) {
167+
t.Spec = api.TaskSpec{
168+
Runtime: &api.TaskSpec_Container{
169+
Container: &api.ContainerSpec{
170+
Hostname: "{{.Node.Hostname}}-{{.Node.Platform.OS}}-{{.Node.Platform.Architecture}}",
171+
},
172+
},
173+
}
174+
}),
175+
NodeDescription: modifyNode(func(n *api.NodeDescription) {
176+
n.Hostname = "mynode"
177+
n.Platform.Architecture = "myarchitecture"
178+
n.Platform.OS = "myos"
179+
}),
180+
Expected: &api.ContainerSpec{
181+
Hostname: "mynode-myos-myarchitecture",
182+
},
183+
},
137184
} {
138185
t.Run(testcase.Test, func(t *testing.T) {
139-
spec, err := ExpandContainerSpec(testcase.Task)
186+
spec, err := ExpandContainerSpec(testcase.NodeDescription, testcase.Task)
140187
if err != nil {
141188
if testcase.Err == nil {
142189
t.Fatalf("unexpected error: %v", err)
@@ -194,6 +241,22 @@ func modifyTask(fn func(t *api.Task)) *api.Task {
194241
return t
195242
}
196243

244+
// modifyNode generates a node with interesting values then calls the function
245+
// with it. The caller can then modify the node and return the result.
246+
func modifyNode(fn func(n *api.NodeDescription)) *api.NodeDescription {
247+
n := &api.NodeDescription{
248+
Hostname: "nodeHostname",
249+
Platform: &api.Platform{
250+
Architecture: "x86_64",
251+
OS: "linux",
252+
},
253+
}
254+
255+
fn(n)
256+
257+
return n
258+
}
259+
197260
// visitAllTemplatedFields does just that.
198261
// TODO(stevvooe): Might be best to make this the actual implementation.
199262
func visitAllTemplatedFields(spec *api.ContainerSpec, fn func(value string)) {

‎template/expand.go

+8-7
Original file line numberDiff line numberDiff line change
@@ -10,18 +10,19 @@ import (
1010
)
1111

1212
// ExpandContainerSpec expands templated fields in the runtime using the task
13-
// state. Templating is all evaluated on the agent-side, before execution.
13+
// state and the node where it is scheduled to run.
14+
// Templating is all evaluated on the agent-side, before execution.
1415
//
1516
// Note that these are projected only on runtime values, since active task
1617
// values are typically manipulated in the manager.
17-
func ExpandContainerSpec(t *api.Task) (*api.ContainerSpec, error) {
18+
func ExpandContainerSpec(n *api.NodeDescription, t *api.Task) (*api.ContainerSpec, error) {
1819
container := t.Spec.GetContainer()
1920
if container == nil {
2021
return nil, errors.Errorf("task missing ContainerSpec to expand")
2122
}
2223

2324
container = container.Copy()
24-
ctx := NewContextFromTask(t)
25+
ctx := NewContext(n, t)
2526

2627
var err error
2728
container.Env, err = expandEnv(ctx, container.Env)
@@ -128,12 +129,12 @@ func expandPayload(ctx PayloadContext, payload []byte) ([]byte, error) {
128129

129130
// ExpandSecretSpec expands the template inside the secret payload, if any.
130131
// Templating is evaluated on the agent-side.
131-
func ExpandSecretSpec(s *api.Secret, t *api.Task, dependencies exec.DependencyGetter) (*api.SecretSpec, error) {
132+
func ExpandSecretSpec(s *api.Secret, node *api.NodeDescription, t *api.Task, dependencies exec.DependencyGetter) (*api.SecretSpec, error) {
132133
if s.Spec.Templating == nil {
133134
return &s.Spec, nil
134135
}
135136
if s.Spec.Templating.Name == "golang" {
136-
ctx := NewPayloadContextFromTask(t, dependencies)
137+
ctx := NewPayloadContextFromTask(node, t, dependencies)
137138
secretSpec := s.Spec.Copy()
138139

139140
var err error
@@ -145,12 +146,12 @@ func ExpandSecretSpec(s *api.Secret, t *api.Task, dependencies exec.DependencyGe
145146

146147
// ExpandConfigSpec expands the template inside the config payload, if any.
147148
// Templating is evaluated on the agent-side.
148-
func ExpandConfigSpec(c *api.Config, t *api.Task, dependencies exec.DependencyGetter) (*api.ConfigSpec, error) {
149+
func ExpandConfigSpec(c *api.Config, node *api.NodeDescription, t *api.Task, dependencies exec.DependencyGetter) (*api.ConfigSpec, error) {
149150
if c.Spec.Templating == nil {
150151
return &c.Spec, nil
151152
}
152153
if c.Spec.Templating.Name == "golang" {
153-
ctx := NewPayloadContextFromTask(t, dependencies)
154+
ctx := NewPayloadContextFromTask(node, t, dependencies)
154155
configSpec := c.Spec.Copy()
155156

156157
var err error

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