Adding ec2tag and ec2region functions

aws/ec2info.go

@@ -0,0 +1,65 @@
+package aws
+
+import (
+	"log"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/ec2"
+)
+
+// Ec2Info -
+type Ec2Info struct {
+	describer  InstanceDescriber
+	metaClient *Ec2Meta
+}
+
+// InstanceDescriber - A subset of ec2iface.EC2API that we can use to call EC2.DescribeInstances
+type InstanceDescriber interface {
+	DescribeInstances(*ec2.DescribeInstancesInput) (*ec2.DescribeInstancesOutput, error)
+}
+
+// var _ InstanceDescriber = (*ec2.EC2)(nil)
+
+// NewEc2Info -
+func NewEc2Info() *Ec2Info {
+	metaClient := &Ec2Meta{}
+	region := metaClient.Region()
+	return &Ec2Info{
+		describer:  ec2Client(region),
+		metaClient: metaClient,
+	}
+}
+
+func ec2Client(region string) (client InstanceDescriber) {
+	config := aws.NewConfig()
+	config = config.WithRegion(region)
+	client = ec2.New(session.New(config))
+	return client
+}
+
+// Tag -
+func (e *Ec2Info) Tag(tag string, def ...string) string {
+	instanceID := e.metaClient.Meta("instance-id")
+	input := &ec2.DescribeInstancesInput{
+		InstanceIds: aws.StringSlice([]string{instanceID}),
+	}
+	output, err := e.describer.DescribeInstances(input)
+	if err != nil {
+		log.Fatalf("Failed to list tag %s: %v", tag, err)
+	}
+	if output != nil && len(output.Reservations) > 0 &&
+		len(output.Reservations[0].Instances) > 0 &&
+		len(output.Reservations[0].Instances[0].Tags) > 0 {
+		for _, v := range output.Reservations[0].Instances[0].Tags {
+			if *v.Key == tag {
+				return *v.Value
+			}
+		}
+	}
+
+	if len(def) > 0 {
+		return def[0]
+	}
+	return ""
+}

aws/ec2info_test.go

@@ -0,0 +1,77 @@
+package aws
+
+import (
+	"testing"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/ec2"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTag_MissingKey(t *testing.T) {
+	server, ec2meta := MockServer(200, `"i-1234"`)
+	defer server.Close()
+	client := &DummyInstanceDescriber{
+		tags: []*ec2.Tag{
+			&ec2.Tag{
+				Key:   aws.String("foo"),
+				Value: aws.String("bar"),
+			},
+			&ec2.Tag{
+				Key:   aws.String("baz"),
+				Value: aws.String("qux"),
+			},
+		},
+	}
+	e := &Ec2Info{
+		describer:  client,
+		metaClient: ec2meta,
+	}
+
+	assert.Empty(t, e.Tag("missing"))
+	assert.Equal(t, "default", e.Tag("missing", "default"))
+}
+
+func TestTag_ValidKey(t *testing.T) {
+	server, ec2meta := MockServer(200, `"i-1234"`)
+	defer server.Close()
+	client := &DummyInstanceDescriber{
+		tags: []*ec2.Tag{
+			&ec2.Tag{
+				Key:   aws.String("foo"),
+				Value: aws.String("bar"),
+			},
+			&ec2.Tag{
+				Key:   aws.String("baz"),
+				Value: aws.String("qux"),
+			},
+		},
+	}
+	e := &Ec2Info{
+		describer:  client,
+		metaClient: ec2meta,
+	}
+
+	assert.Equal(t, "bar", e.Tag("foo"))
+	assert.Equal(t, "bar", e.Tag("foo", "default"))
+}
+
+// test doubles
+type DummyInstanceDescriber struct {
+	tags []*ec2.Tag
+}
+
+func (d *DummyInstanceDescriber) DescribeInstances(*ec2.DescribeInstancesInput) (*ec2.DescribeInstancesOutput, error) {
+	output := &ec2.DescribeInstancesOutput{
+		Reservations: []*ec2.Reservation{
+			&ec2.Reservation{
+				Instances: []*ec2.Instance{
+					&ec2.Instance{
+						Tags: d.tags,
+					},
+				},
+			},
+		},
+	}
+	return output, nil
+}

aws/ec2meta.go

@@ -1,6 +1,7 @@
 package aws
 
 import (
+	"encoding/json"
 	"io/ioutil"
 	"log"
 	"net/http"
@@ -41,8 +42,8 @@ func (e *Ec2Meta) retrieveMetadata(url string, key string, def ...string) string
 	return value
 }
 
-// Ec2meta -
-func (e *Ec2Meta) Ec2meta(key string, def ...string) string {
+// Meta -
+func (e *Ec2Meta) Meta(key string, def ...string) string {
 	if e.Endpoint == "" {
 		e.Endpoint = DefaultEndpoint
 	}
@@ -51,12 +52,37 @@ func (e *Ec2Meta) Ec2meta(key string, def ...string) string {
 	return e.retrieveMetadata(url, key, def...)
 }
 
-// Ec2dynamic -
-func (e *Ec2Meta) Ec2dynamic(key string, def ...string) string {
+// Dynamic -
+func (e *Ec2Meta) Dynamic(key string, def ...string) string {
 	if e.Endpoint == "" {
 		e.Endpoint = DefaultEndpoint
 	}
 
 	url := e.Endpoint + "/latest/dynamic/" + key
 	return e.retrieveMetadata(url, key, def...)
 }
+
+// Region -
+func (e *Ec2Meta) Region() string {
+	doc := e.Dynamic("instance-identity/document", `{"region":"unknown"}`)
+	obj := &InstanceDocument{
+		Region: "unknown",
+	}
+	err := json.Unmarshal([]byte(doc), &obj)
+	if err != nil {
+		log.Fatalf("Unable to unmarshal JSON object %s: %v", doc, err)
+	}
+	return obj.Region
+}
+
+// InstanceDocument -
+type InstanceDocument struct {
+	PrivateIP        string `json:"privateIp"`
+	AvailabilityZone string `json:"availabilityZone"`
+	InstanceID       string `json:"InstanceId"`
+	InstanceType     string `json:"InstanceType"`
+	AccountID        string `json:"AccountId"`
+	ImageID          string `json:"imageId"`
+	Architecture     string `json:"architecture"`
+	Region           string `json:"region"`
+}

aws/ec2meta_test.go

@@ -6,34 +6,48 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestEc2meta_MissingKey(t *testing.T) {
+func TestMeta_MissingKey(t *testing.T) {
 	server, ec2meta := MockServer(404, "")
 	defer server.Close()
 
-	assert.Empty(t, ec2meta.Ec2meta("foo"))
-	assert.Equal(t, "default", ec2meta.Ec2meta("foo", "default"))
+	assert.Empty(t, ec2meta.Meta("foo"))
+	assert.Equal(t, "default", ec2meta.Meta("foo", "default"))
 }
 
-func TestEc2meta_ValidKey(t *testing.T) {
+func TestMeta_ValidKey(t *testing.T) {
 	server, ec2meta := MockServer(200, "i-1234")
 	defer server.Close()
 
-	assert.Equal(t, "i-1234", ec2meta.Ec2meta("instance-id"))
-	assert.Equal(t, "i-1234", ec2meta.Ec2meta("instance-id", "unused default"))
+	assert.Equal(t, "i-1234", ec2meta.Meta("instance-id"))
+	assert.Equal(t, "i-1234", ec2meta.Meta("instance-id", "unused default"))
 }
 
-func TestEc2dynamic_MissingKey(t *testing.T) {
+func TestDynamic_MissingKey(t *testing.T) {
 	server, ec2meta := MockServer(404, "")
 	defer server.Close()
 
-	assert.Empty(t, ec2meta.Ec2dynamic("foo"))
-	assert.Equal(t, "default", ec2meta.Ec2dynamic("foo", "default"))
+	assert.Empty(t, ec2meta.Dynamic("foo"))
+	assert.Equal(t, "default", ec2meta.Dynamic("foo", "default"))
 }
 
-func TestEc2dynamic_ValidKey(t *testing.T) {
+func TestDynamic_ValidKey(t *testing.T) {
 	server, ec2meta := MockServer(200, "i-1234")
 	defer server.Close()
 
-	assert.Equal(t, "i-1234", ec2meta.Ec2dynamic("instance-id"))
-	assert.Equal(t, "i-1234", ec2meta.Ec2dynamic("instance-id", "unused default"))
+	assert.Equal(t, "i-1234", ec2meta.Dynamic("instance-id"))
+	assert.Equal(t, "i-1234", ec2meta.Dynamic("instance-id", "unused default"))
+}
+
+func TestRegion_NoRegion(t *testing.T) {
+	server, ec2meta := MockServer(200, "{}")
+	defer server.Close()
+
+	assert.Equal(t, "unknown", ec2meta.Region())
+}
+
+func TestRegion_KnownRegion(t *testing.T) {
+	server, ec2meta := MockServer(200, `{"region":"us-east-1"}`)
+	defer server.Close()
+
+	assert.Equal(t, "us-east-1", ec2meta.Region())
 }

main.go

@@ -57,18 +57,16 @@ func NewGomplate() *Gomplate {
 	env := &Env{}
 	typeconv := &TypeConv{}
 	ec2meta := &aws.Ec2Meta{}
+	ec2info := aws.NewEc2Info()
 	return &Gomplate{
 		funcMap: template.FuncMap{
-			"Getenv":     env.Getenv,
 			"getenv":     env.Getenv,
-			"Bool":       typeconv.Bool,
 			"bool":       typeconv.Bool,
-			"JSON":       typeconv.JSON,
 			"json":       typeconv.JSON,
-			"Ec2meta":    ec2meta.Ec2meta,
-			"ec2meta":    ec2meta.Ec2meta,
-			"Ec2dynamic": ec2meta.Ec2dynamic,
-			"ec2dynamic": ec2meta.Ec2dynamic,
+			"ec2meta":    ec2meta.Meta,
+			"ec2dynamic": ec2meta.Dynamic,
+			"ec2tag":     ec2info.Tag,
+			"region":     ec2meta.Region,
 		},
 	}
 }

main_test.go

@@ -20,14 +20,28 @@ func testTemplate(g *Gomplate, template string) string {
 }
 
 func TestGetenvTemplates(t *testing.T) {
-	g := NewGomplate()
+	env := &Env{}
+	typeconv := &TypeConv{}
+	g := &Gomplate{
+		funcMap: template.FuncMap{
+			"getenv": env.Getenv,
+			"bool":   typeconv.Bool,
+		},
+	}
 	assert.Empty(t, testTemplate(g, `{{getenv "BLAHBLAHBLAH"}}`))
 	assert.Equal(t, os.Getenv("USER"), testTemplate(g, `{{getenv "USER"}}`))
 	assert.Equal(t, "default value", testTemplate(g, `{{getenv "BLAHBLAHBLAH" "default value"}}`))
 }
 
 func TestBoolTemplates(t *testing.T) {
-	g := NewGomplate()
+	env := &Env{}
+	typeconv := &TypeConv{}
+	g := &Gomplate{
+		funcMap: template.FuncMap{
+			"getenv": env.Getenv,
+			"bool":   typeconv.Bool,
+		},
+	}
 	assert.Equal(t, "true", testTemplate(g, `{{bool "true"}}`))
 	assert.Equal(t, "false", testTemplate(g, `{{bool "false"}}`))
 	assert.Equal(t, "false", testTemplate(g, `{{bool "foo"}}`))
@@ -39,7 +53,7 @@ func TestEc2MetaTemplates_MissingKey(t *testing.T) {
 	defer server.Close()
 	g := &Gomplate{
 		funcMap: template.FuncMap{
-			"ec2meta": ec2meta.Ec2meta,
+			"ec2meta": ec2meta.Meta,
 		},
 	}
 
@@ -52,7 +66,7 @@ func TestEc2MetaTemplates_ValidKey(t *testing.T) {
 	defer server.Close()
 	g := &Gomplate{
 		funcMap: template.FuncMap{
-			"ec2meta": ec2meta.Ec2meta,
+			"ec2meta": ec2meta.Meta,
 		},
 	}
 
@@ -66,8 +80,8 @@ func TestEc2MetaTemplates_WithJSON(t *testing.T) {
 	ty := new(TypeConv)
 	g := &Gomplate{
 		funcMap: template.FuncMap{
-			"ec2meta":    ec2meta.Ec2meta,
-			"ec2dynamic": ec2meta.Ec2dynamic,
+			"ec2meta":    ec2meta.Meta,
+			"ec2dynamic": ec2meta.Dynamic,
 			"json":       ty.JSON,
 		},
 	}