datasource/waagent: add support for WAAgent metadata

datasource/waagent/waagent.go

@@ -0,0 +1,108 @@
+package waagent
+
+import (
+	"encoding/json"
+	"encoding/xml"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os"
+	"path"
+)
+
+type waagent struct {
+	root     string
+	readFile func(filename string) ([]byte, error)
+}
+
+func NewDatasource(root string) *waagent {
+	return &waagent{root, ioutil.ReadFile}
+}
+
+func (a *waagent) IsAvailable() bool {
+	_, err := os.Stat(path.Join(a.root, "provisioned"))
+	return !os.IsNotExist(err)
+}
+
+func (a *waagent) AvailabilityChanges() bool {
+	return true
+}
+
+func (a *waagent) ConfigRoot() string {
+	return a.root
+}
+
+func (a *waagent) FetchMetadata() ([]byte, error) {
+	metadataBytes, err := a.tryReadFile(path.Join(a.root, "SharedConfig.xml"))
+	if err != nil {
+		return nil, err
+	}
+	if len(metadataBytes) == 0 {
+		return metadataBytes, nil
+	}
+
+	type Instance struct {
+		Id             string `xml:"id,attr"`
+		Address        string `xml:"address,attr"`
+		InputEndpoints struct {
+			Endpoints []struct {
+				LoadBalancedPublicAddress string `xml:"loadBalancedPublicAddress,attr"`
+			} `xml:"Endpoint"`
+		}
+	}
+
+	type SharedConfig struct {
+		Incarnation struct {
+			Instance string `xml:"instance,attr"`
+		}
+		Instances struct {
+			Instances []Instance `xml:"Instance"`
+		}
+	}
+
+	var metadata SharedConfig
+	if err := xml.Unmarshal(metadataBytes, &metadata); err != nil {
+		return nil, err
+	}
+
+	var instance Instance
+	for _, i := range metadata.Instances.Instances {
+		if i.Id == metadata.Incarnation.Instance {
+			instance = i
+			break
+		}
+	}
+
+	attrs := map[string]string{
+		"local-ipv4": instance.Address,
+	}
+	for _, e := range instance.InputEndpoints.Endpoints {
+		host, _, err := net.SplitHostPort(e.LoadBalancedPublicAddress)
+		if err == nil {
+			attrs["public-ipv4"] = host
+			break
+		}
+	}
+	return json.Marshal(attrs)
+}
+
+func (a *waagent) FetchUserdata() ([]byte, error) {
+	return a.tryReadFile(path.Join(a.root, "CustomData"))
+}
+
+func (a *waagent) FetchNetworkConfig(filename string) ([]byte, error) {
+	return nil, nil
+}
+
+func (a *waagent) Type() string {
+	return "waagent"
+}
+
+func (a *waagent) tryReadFile(filename string) ([]byte, error) {
+	fmt.Printf("Attempting to read from %q\n", filename)
+	data, err := a.readFile(filename)
+	if os.IsNotExist(err) {
+		err = nil
+	}
+	return data, err
+}

datasource/waagent/waagent_test.go

@@ -0,0 +1,168 @@
+package waagent
+
+import (
+	"encoding/json"
+	"os"
+	"reflect"
+	"testing"
+)
+
+type mockFilesystem map[string][]byte
+
+func (m mockFilesystem) readFile(filename string) ([]byte, error) {
+	if contents := m[filename]; contents != nil {
+		return contents, nil
+	}
+	return nil, os.ErrNotExist
+}
+
+func TestFetchMetadata(t *testing.T) {
+	for _, tt := range []struct {
+		root     string
+		files    mockFilesystem
+		metadata map[string]string
+	}{
+		{
+			"/",
+			mockFilesystem{},
+			nil,
+		},
+		{
+			"/",
+			mockFilesystem{"/SharedConfig.xml": []byte("")},
+			nil,
+		},
+		{
+			"/var/lib/waagent",
+			mockFilesystem{"/var/lib/waagent/SharedConfig.xml": []byte("")},
+			nil,
+		},
+		{
+			"/var/lib/waagent",
+			mockFilesystem{"/var/lib/waagent/SharedConfig.xml": []byte(`<?xml version="1.0" encoding="utf-8"?>
+<SharedConfig version="1.0.0.0" goalStateIncarnation="1">
+  <Deployment name="c8f9e4c9c18948e1bebf57c5685da756" guid="{1d10394f-c741-4a1a-a6bb-278f213c5a5e}" incarnation="0" isNonCancellableTopologyChangeEnabled="false">
+    <Service name="core-test-1" guid="{00000000-0000-0000-0000-000000000000}" />
+    <ServiceInstance name="c8f9e4c9c18948e1bebf57c5685da756.0" guid="{1e202e9a-8ffe-4915-b6ef-4118c9628fda}" />
+  </Deployment>
+  <Incarnation number="1" instance="core-test-1" guid="{8767eb4b-b445-4783-b1f5-6c0beaf41ea0}" />
+  <Role guid="{53ecc81e-257f-fbc9-a53a-8cf1a0a122b4}" name="core-test-1" settleTimeSeconds="0" />
+  <LoadBalancerSettings timeoutSeconds="0" waitLoadBalancerProbeCount="8">
+    <Probes>
+      <Probe name="D41D8CD98F00B204E9800998ECF8427E" />
+      <Probe name="C9DEC1518E1158748FA4B6081A8266DD" />
+    </Probes>
+  </LoadBalancerSettings>
+  <OutputEndpoints>
+    <Endpoint name="core-test-1:openInternalEndpoint" type="SFS">
+      <Target instance="core-test-1" endpoint="openInternalEndpoint" />
+    </Endpoint>
+  </OutputEndpoints>
+  <Instances>
+    <Instance id="core-test-1" address="100.73.202.64">
+      <FaultDomains randomId="0" updateId="0" updateCount="0" />
+      <InputEndpoints>
+        <Endpoint name="openInternalEndpoint" address="100.73.202.64" protocol="any" isPublic="false" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
+          <LocalPorts>
+            <LocalPortSelfManaged />
+          </LocalPorts>
+        </Endpoint>
+        <Endpoint name="ssh" address="100.73.202.64:22" protocol="tcp" hostName="core-test-1ContractContract" isPublic="true" loadBalancedPublicAddress="191.239.39.77:22" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
+          <LocalPorts>
+            <LocalPortRange from="22" to="22" />
+          </LocalPorts>
+        </Endpoint>
+      </InputEndpoints>
+    </Instance>
+  </Instances>
+</SharedConfig>`)},
+			map[string]string{
+				"local-ipv4":  "100.73.202.64",
+				"public-ipv4": "191.239.39.77",
+			},
+		},
+	} {
+		a := waagent{tt.root, tt.files.readFile}
+		metadataBytes, err := a.FetchMetadata()
+		if err != nil {
+			t.Fatalf("bad error for %q: want %q, got %q", tt, nil, err)
+		}
+		var metadata map[string]string
+		if len(metadataBytes) > 0 {
+			if err := json.Unmarshal(metadataBytes, &metadata); err != nil {
+				panic(err)
+			}
+		}
+		if !reflect.DeepEqual(tt.metadata, metadata) {
+			t.Fatalf("bad metadata for %q: want %q, got %q", tt, tt.metadata, metadata)
+		}
+	}
+}
+
+func TestFetchUserdata(t *testing.T) {
+	for _, tt := range []struct {
+		root  string
+		files mockFilesystem
+	}{
+		{
+			"/",
+			mockFilesystem{},
+		},
+		{
+			"/",
+			mockFilesystem{"/CustomData": []byte{}},
+		},
+		{
+			"/var/lib/waagent/",
+			mockFilesystem{"/var/lib/waagent/CustomData": []byte{}},
+		},
+	} {
+		a := waagent{tt.root, tt.files.readFile}
+		_, err := a.FetchUserdata()
+		if err != nil {
+			t.Fatalf("bad error for %q: want %q, got %q", tt, nil, err)
+		}
+	}
+}
+
+func TestConfigRoot(t *testing.T) {
+	for _, tt := range []struct {
+		root       string
+		configRoot string
+	}{
+		{
+			"/",
+			"/",
+		},
+		{
+			"/var/lib/waagent",
+			"/var/lib/waagent",
+		},
+	} {
+		a := waagent{tt.root, nil}
+		if configRoot := a.ConfigRoot(); configRoot != tt.configRoot {
+			t.Fatalf("bad config root for %q: want %q, got %q", tt, tt.configRoot, configRoot)
+		}
+	}
+}
+
+func TestNewDatasource(t *testing.T) {
+	for _, tt := range []struct {
+		root       string
+		expectRoot string
+	}{
+		{
+			root:       "",
+			expectRoot: "",
+		},
+		{
+			root:       "/var/lib/waagent",
+			expectRoot: "/var/lib/waagent",
+		},
+	} {
+		service := NewDatasource(tt.root)
+		if service.root != tt.expectRoot {
+			t.Fatalf("bad root (%q): want %q, got %q", tt.root, tt.expectRoot, service.root)
+		}
+	}
+}

test

@@ -24,6 +24,7 @@ declare -a TESTPKGS=(
 	datasource/metadata/ec2
 	datasource/proc_cmdline
 	datasource/url
+	datasource/waagent
 	initialize
 	network
 	pkg