Add support for accessing metadata in swarm templates (#412)

Signed-off-by: David Chung <[email protected]>

Author: David Chung

cmd/cli/manager.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/infrakit/pkg/discovery"
 	"github.com/docker/infrakit/pkg/manager"
 	"github.com/docker/infrakit/pkg/plugin"
+	metadata_template "github.com/docker/infrakit/pkg/plugin/metadata/template"
 	"github.com/docker/infrakit/pkg/rpc/client"
 	group_plugin "github.com/docker/infrakit/pkg/rpc/group"
 	manager_rpc "github.com/docker/infrakit/pkg/rpc/manager"
@@ -91,6 +92,21 @@ func managerCommand(plugins func() discovery.Plugins) *cobra.Command {
 		if err != nil {
 			return err
 		}
+
+		engine.WithFunctions(func() []template.Function {
+			return []template.Function{
+				{
+					Name: "metadata",
+					Description: []string{
+						"Metadata function takes a path of the form \"plugin_name/path/to/data\"",
+						"and calls GET on the plugin with the path \"path/to/data\".",
+						"It's identical to the CLI command infrakit metadata cat ...",
+					},
+					Func: metadata_template.MetadataFunc(plugins),
+				},
+			}
+		})
+
 		view, err := engine.Render(nil)
 		if err != nil {
 			return err

cmd/cli/metadata.go

@@ -213,18 +213,21 @@ func metadataCommand(plugins func() discovery.Plugins) *cobra.Command {
 						return err
 					}
 
-					value, err := match.Get(path.Shift(1))
-					if err == nil {
-						if value != nil {
-							str := value.String()
-							if s, err := strconv.Unquote(value.String()); err == nil {
-								str = s
+					if path.Len() == 1 {
+						fmt.Printf("%v\n", match != nil)
+					} else {
+						value, err := match.Get(path.Shift(1))
+						if err == nil {
+							if value != nil {
+								str := value.String()
+								if s, err := strconv.Unquote(value.String()); err == nil {
+									str = s
+								}
+								fmt.Println(str)
 							}
-							fmt.Println(str)
+						} else {
+							log.Warningln("Cannot metadata cat on plugin", *first, "err=", err)
 						}
-
-					} else {
-						log.Warningln("Cannot metadata cat on plugin", *first, "err=", err)
 					}
 				}
 			}

cmd/cli/template.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"strings"
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/infrakit/pkg/discovery"
@@ -12,6 +13,7 @@ import (
 
 func templateCommand(plugins func() discovery.Plugins) *cobra.Command {
 
+	globals := []string{}
 	templateURL := ""
 	cmd := &cobra.Command{
 		Use:   "template",
@@ -27,6 +29,18 @@ func templateCommand(plugins func() discovery.Plugins) *cobra.Command {
 			}
 
 			// Add functions
+			for _, global := range globals {
+				kv := strings.Split(global, "=")
+				if len(kv) != 2 {
+					continue
+				}
+				key := strings.Trim(kv[0], " \t\n")
+				val := strings.Trim(kv[1], " \t\n")
+				if key != "" && val != "" {
+					engine.Global(key, val)
+				}
+			}
+
 			engine.WithFunctions(func() []template.Function {
 				return []template.Function{
 					{
@@ -50,6 +64,7 @@ func templateCommand(plugins func() discovery.Plugins) *cobra.Command {
 		},
 	}
 	cmd.Flags().StringVar(&templateURL, "url", "", "URL for the template")
+	cmd.Flags().StringSliceVar(&globals, "global", []string{}, "key=value pairs of 'global' values")
 
 	return cmd
 }

examples/flavor/swarm/flavor.go

@@ -10,8 +10,10 @@ import (
 	"github.com/docker/docker/api/types/swarm"
 	"github.com/docker/docker/client"
 	"github.com/docker/go-connections/tlsconfig"
+	"github.com/docker/infrakit/pkg/discovery"
 	group_types "github.com/docker/infrakit/pkg/plugin/group/types"
 	metadata_plugin "github.com/docker/infrakit/pkg/plugin/metadata"
+	metadata_template "github.com/docker/infrakit/pkg/plugin/metadata/template"
 	"github.com/docker/infrakit/pkg/spi/flavor"
 	"github.com/docker/infrakit/pkg/spi/instance"
 	"github.com/docker/infrakit/pkg/spi/metadata"
@@ -65,6 +67,7 @@ type baseFlavor struct {
 	getDockerClient func(Spec) (client.APIClient, error)
 	initScript      *template.Template
 	metadataPlugin  metadata.Plugin
+	plugins         func() discovery.Plugins
 }
 
 // Runs a poller that periodically samples the swarm status and node info.
@@ -183,6 +186,11 @@ func (s *baseFlavor) prepare(role string, flavorProperties *types.Any, instanceS
 	allocation group_types.AllocationMethod) (instance.Spec, error) {
 
 	spec := Spec{}
+
+	if s.plugins == nil {
+		return instanceSpec, fmt.Errorf("no plugin discovery")
+	}
+
 	err := flavorProperties.Decode(&spec)
 	if err != nil {
 		return instanceSpec, err
@@ -217,7 +225,7 @@ func (s *baseFlavor) prepare(role string, flavorProperties *types.Any, instanceS
 
 		swarmStatus, node, err = swarmState(dockerClient)
 		if err != nil {
-			log.Warningln("Worker prepare:", err)
+			log.Warningln("Cannot prepare:", err)
 		}
 
 		swarmID = "?"
@@ -235,6 +243,19 @@ func (s *baseFlavor) prepare(role string, flavorProperties *types.Any, instanceS
 			link:         *link,
 		}
 
+		initTemplate.WithFunctions(func() []template.Function {
+			return []template.Function{
+				{
+					Name: "metadata",
+					Description: []string{
+						"Metadata function takes a path of the form \"plugin_name/path/to/data\"",
+						"and calls GET on the plugin with the path \"path/to/data\".",
+						"It's identical to the CLI command infrakit metadata cat ...",
+					},
+					Func: metadata_template.MetadataFunc(s.plugins),
+				},
+			}
+		})
 		initScript, err = initTemplate.Render(context)
 
 		log.Debugln(role, ">>> context.retries =", context.retries, "err=", err, "i=", i)

examples/flavor/swarm/flavor_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/docker/api/types/filters"
 	"github.com/docker/docker/api/types/swarm"
 	docker_client "github.com/docker/docker/client"
+	"github.com/docker/infrakit/pkg/discovery"
 	mock_client "github.com/docker/infrakit/pkg/mock/docker/docker/client"
 	group_types "github.com/docker/infrakit/pkg/plugin/group/types"
 	"github.com/docker/infrakit/pkg/spi/flavor"
@@ -26,16 +27,24 @@ func templ(tpl string) *template.Template {
 	return t
 }
 
+func plugins() discovery.Plugins {
+	d, err := discovery.NewPluginDiscovery()
+	if err != nil {
+		panic(err)
+	}
+	return d
+}
+
 func TestValidate(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	defer ctrl.Finish()
 	managerStop := make(chan struct{})
 	workerStop := make(chan struct{})
 
-	managerFlavor := NewManagerFlavor(func(Spec) (docker_client.APIClient, error) {
+	managerFlavor := NewManagerFlavor(plugins, func(Spec) (docker_client.APIClient, error) {
 		return mock_client.NewMockAPIClient(ctrl), nil
 	}, templ(DefaultManagerInitScriptTemplate), managerStop)
-	workerFlavor := NewWorkerFlavor(func(Spec) (docker_client.APIClient, error) {
+	workerFlavor := NewWorkerFlavor(plugins, func(Spec) (docker_client.APIClient, error) {
 		return mock_client.NewMockAPIClient(ctrl), nil
 	}, templ(DefaultWorkerInitScriptTemplate), workerStop)
 
@@ -90,7 +99,7 @@ func TestWorker(t *testing.T) {
 
 	client := mock_client.NewMockAPIClient(ctrl)
 
-	flavorImpl := NewWorkerFlavor(func(Spec) (docker_client.APIClient, error) {
+	flavorImpl := NewWorkerFlavor(plugins, func(Spec) (docker_client.APIClient, error) {
 		return client, nil
 	}, templ(DefaultWorkerInitScriptTemplate), workerStop)
 
@@ -160,7 +169,7 @@ func TestManager(t *testing.T) {
 
 	client := mock_client.NewMockAPIClient(ctrl)
 
-	flavorImpl := NewManagerFlavor(func(Spec) (docker_client.APIClient, error) {
+	flavorImpl := NewManagerFlavor(plugins, func(Spec) (docker_client.APIClient, error) {
 		return client, nil
 	}, templ(DefaultManagerInitScriptTemplate), managerStop)
 

examples/flavor/swarm/main.go

@@ -29,10 +29,20 @@ var defaultTemplateOptions = template.Options{
 
 func main() {
 
+	plugins := func() discovery.Plugins {
+		d, err := discovery.NewPluginDiscovery()
+		if err != nil {
+			log.Fatalf("Failed to initialize plugin discovery: %s", err)
+			os.Exit(1)
+		}
+		return d
+	}
+
 	cmd := &cobra.Command{
 		Use:   os.Args[0],
 		Short: "Docker Swarm flavor plugin",
 	}
+
 	name := cmd.Flags().String("name", "flavor-swarm", "Plugin name to advertise for discovery")
 	logLevel := cmd.Flags().Int("log", cli.DefaultLogLevel, "Logging level. 0 is least verbose. Max is 5")
 	managerInitScriptTemplURL := cmd.Flags().String("manager-init-template", "", "URL, init script template for managers")
@@ -53,8 +63,9 @@ func main() {
 
 		managerStop := make(chan struct{})
 		workerStop := make(chan struct{})
-		managerFlavor := NewManagerFlavor(DockerClient, mt, managerStop)
-		workerFlavor := NewWorkerFlavor(DockerClient, wt, workerStop)
+
+		managerFlavor := NewManagerFlavor(plugins, DockerClient, mt, managerStop)
+		workerFlavor := NewWorkerFlavor(plugins, DockerClient, wt, workerStop)
 
 		cli.RunPlugin(*name,
 

examples/flavor/swarm/manager.go

@@ -5,6 +5,7 @@ import (
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/docker/docker/client"
+	"github.com/docker/infrakit/pkg/discovery"
 	group_types "github.com/docker/infrakit/pkg/plugin/group/types"
 	"github.com/docker/infrakit/pkg/plugin/metadata"
 	"github.com/docker/infrakit/pkg/spi/instance"
@@ -13,10 +14,11 @@ import (
 )
 
 // NewManagerFlavor creates a flavor.Plugin that creates manager and worker nodes connected in a swarm.
-func NewManagerFlavor(connect func(Spec) (client.APIClient, error), templ *template.Template,
+func NewManagerFlavor(plugins func() discovery.Plugins, connect func(Spec) (client.APIClient, error),
+	templ *template.Template,
 	stop <-chan struct{}) *ManagerFlavor {
 
-	base := &baseFlavor{initScript: templ, getDockerClient: connect}
+	base := &baseFlavor{initScript: templ, getDockerClient: connect, plugins: plugins}
 	base.metadataPlugin = metadata.NewPluginFromChannel(base.runMetadataSnapshot(stop))
 	return &ManagerFlavor{baseFlavor: base}
 }

examples/flavor/swarm/worker.go

@@ -7,6 +7,7 @@ import (
 	docker_types "github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
 	"github.com/docker/docker/client"
+	"github.com/docker/infrakit/pkg/discovery"
 	group_types "github.com/docker/infrakit/pkg/plugin/group/types"
 	"github.com/docker/infrakit/pkg/plugin/metadata"
 	"github.com/docker/infrakit/pkg/spi/instance"
@@ -16,10 +17,11 @@ import (
 )
 
 // NewWorkerFlavor creates a flavor.Plugin that creates manager and worker nodes connected in a swarm.
-func NewWorkerFlavor(connect func(Spec) (client.APIClient, error), templ *template.Template,
+func NewWorkerFlavor(plugins func() discovery.Plugins, connect func(Spec) (client.APIClient, error),
+	templ *template.Template,
 	stop <-chan struct{}) *WorkerFlavor {
 
-	base := &baseFlavor{initScript: templ, getDockerClient: connect}
+	base := &baseFlavor{initScript: templ, getDockerClient: connect, plugins: plugins}
 	base.metadataPlugin = metadata.NewPluginFromChannel(base.runMetadataSnapshot(stop))
 	return &WorkerFlavor{baseFlavor: base}
 }

pkg/plugin/metadata/reflect.go

@@ -42,29 +42,27 @@ func List(path []string, object interface{}) []string {
 	if v == nil {
 		return list
 	}
+
+	val := reflect.Indirect(reflect.ValueOf(v))
 	if any, is := v.(*types.Any); is {
-		temp := map[string]interface{}{}
+		var temp interface{}
 		if err := any.Decode(&temp); err == nil {
-			if len(temp) > 0 {
-				return List([]string{"."}, temp)
-			}
-			return []string{}
+			val = reflect.ValueOf(temp)
 		}
-		return []string{}
 	}
 
-	val := reflect.Indirect(reflect.ValueOf(v))
 	switch val.Kind() {
 	case reflect.Slice:
 		// this is a slice, so return the name as '[%d]'
 		for i := 0; i < val.Len(); i++ {
-			list = append(list, fmt.Sprintf("[%d]", i)) //val.Index(i).String())
+			list = append(list, fmt.Sprintf("[%d]", i))
 		}
 
 	case reflect.Map:
 		for _, k := range val.MapKeys() {
 			list = append(list, k.String())
 		}
+
 	case reflect.Struct:
 		vt := val.Type()
 		for i := 0; i < vt.NumField(); i++ {
@@ -122,6 +120,14 @@ func get(path []string, object interface{}) interface{} {
 		return object
 	}
 
+	if any, is := object.(*types.Any); is {
+		var temp interface{}
+		if err := any.Decode(&temp); err == nil {
+			return get(path, temp)
+		}
+		return nil
+	}
+
 	key := path[0]
 
 	switch key {
@@ -139,14 +145,6 @@ func get(path []string, object interface{}) interface{} {
 		return get(path, object)
 	}
 
-	if any, is := object.(*types.Any); is {
-		temp := map[string]interface{}{}
-		if err := any.Decode(&temp); err == nil {
-			return get(path[1:], temp)
-		}
-		return nil
-	}
-
 	v := reflect.Indirect(reflect.ValueOf(object))
 	switch v.Kind() {
 	case reflect.Slice:

pkg/plugin/metadata/reflect_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"testing"
 
+	"github.com/docker/infrakit/pkg/types"
 	"github.com/stretchr/testify/require"
 )
 
@@ -38,9 +39,10 @@ func TestMap(t *testing.T) {
 	require.True(t, put(Path("region/us-west-2/vpc/vpc21/network/network210/id"), "id-network210", m))
 	require.True(t, put(Path("region/us-west-2/vpc/vpc21/network/network211/id"), "id-network211", m))
 	require.True(t, put(Path("region/us-west-2/metrics/instances/count"), 100, m))
+	require.True(t, put(Path("region/us-west-2/instances"), types.AnyValueMust([]string{"a", "b"}), m))
 
-	require.Equal(t, "id-network1", get(Path("region/us-west-1/vpc/vpc1/network/network1/id"), m))
-	require.Equal(t, "id-network1", get(Path("region/us-west-1/vpc/vpc1/network/network1/id/"), m))
+	require.Equal(t, "id-network1", Get(Path("region/us-west-1/vpc/vpc1/network/network1/id"), m))
+	require.Equal(t, "id-network1", Get(Path("region/us-west-1/vpc/vpc1/network/network1/id/"), m))
 	require.Equal(t, map[string]interface{}{"id": "id-network1"},
 		get(Path("region/us-west-1/vpc/vpc1/network/network1"), m))
 	require.Equal(t, map[string]interface{}{
@@ -65,6 +67,12 @@ func TestMap(t *testing.T) {
 	require.Equal(t, []string{"us-west-1", "us-west-2"}, List(Path("region"), m))
 	require.Equal(t, []string{"network1", "network2", "network3"}, List(Path("region/us-west-1/vpc/vpc1/network/"), m))
 	require.Equal(t, []string{}, List(Path("region/us-west-2/metrics/instances/count"), m))
+	require.Equal(t, []string{"[0]", "[1]"}, List(Path("region/us-west-2/instances"), m))
+	require.Equal(t, []string{}, List(Path("region/us-west-2/instances/[0]"), m))
+	require.Equal(t, "a", Get(Path("region/us-west-2/instances/[0]"), m))
+	require.Equal(t, "b", Get(Path("region/us-west-2/instances/[1]"), m))
+	require.Equal(t, "a", Get(Path("region/us-west-2/instances[0]"), m))
+	require.Equal(t, "b", Get(Path("region/us-west-2/instances[1]"), m))
 
 }