aws/ec2metadata: Add support for EC2 User Data (#872)

Adds the `GetUserData` method to `EC2Metadata` client. This allows you to get instance user data from the `/latest/user-data` EC2 metadata endpoint. If the instance does not have any data set the error code `NotFoundError` will be returned. If any data is set that value as a string will be returned by the method. Fix #852
aws · Oct 5, 2016 · 5717392 · 5717392
1 parent 7eb100e
commit 5717392
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diff --git a/aws/ec2metadata/api.go b/aws/ec2metadata/api.go
@@ -3,6 +3,7 @@ package ec2metadata
 import (
 	"encoding/json"
 	"fmt"
+	"net/http"
 	"path"
 	"strings"
 	"time"
@@ -27,6 +28,27 @@ func (c *EC2Metadata) GetMetadata(p string) (string, error) {
 	return output.Content, req.Send()
 }
 
+// GetUserData returns the userdata that was configured for the service. If
+// there is no user-data setup for the EC2 instance a "NotFoundError" error
+// code will be returned.
+func (c *EC2Metadata) GetUserData() (string, error) {
+	op := &request.Operation{
+		Name:       "GetUserData",
+		HTTPMethod: "GET",
+		HTTPPath:   path.Join("/", "user-data"),
+	}
+
+	output := &metadataOutput{}
+	req := c.NewRequest(op, nil, output)
+	req.Handlers.UnmarshalError.PushBack(func(r *request.Request) {
+		if r.HTTPResponse.StatusCode == http.StatusNotFound {
+			r.Error = awserr.New("NotFoundError", "user-data not found", r.Error)
+		}
+	})
+
+	return output.Content, req.Send()
+}
+
 // GetDynamicData uses the path provided to request information from the EC2
 // instance metadata service for dynamic data. The content will be returned
 // as a string, or error if the request failed.

diff --git a/aws/ec2metadata/api_test.go b/aws/ec2metadata/api_test.go
@@ -2,6 +2,8 @@ package ec2metadata_test
 
 import (
 	"bytes"
+	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
@@ -87,6 +89,51 @@ func TestGetMetadata(t *testing.T) {
 	assert.Equal(t, "success", resp)
 }
 
+func TestGetUserData(t *testing.T) {
+	server := initTestServer(
+		"/latest/user-data",
+		"success", // real response includes suffix
+	)
+	defer server.Close()
+	c := ec2metadata.New(unit.Session, &aws.Config{Endpoint: aws.String(server.URL + "/latest")})
+
+	resp, err := c.GetUserData()
+
+	assert.NoError(t, err)
+	assert.Equal(t, "success", resp)
+}
+
+func TestGetUserData_Error(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		reader := strings.NewReader(`<?xml version="1.0" encoding="iso-8859-1"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+         "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+ <head>
+  <title>404 - Not Found</title>
+ </head>
+ <body>
+  <h1>404 - Not Found</h1>
+ </body>
+</html>`)
+		w.Header().Set("Content-Type", "text/html")
+		w.Header().Set("Content-Length", fmt.Sprintf("%d", reader.Len()))
+		w.WriteHeader(http.StatusNotFound)
+		io.Copy(w, reader)
+	}))
+
+	defer server.Close()
+	c := ec2metadata.New(unit.Session, &aws.Config{Endpoint: aws.String(server.URL + "/latest")})
+
+	resp, err := c.GetUserData()
+	assert.Error(t, err)
+	assert.Empty(t, resp)
+
+	aerr, ok := err.(awserr.Error)
+	assert.True(t, ok)
+	assert.Equal(t, "NotFoundError", aerr.Code())
+}
+
 func TestGetRegion(t *testing.T) {
 	server := initTestServer(
 		"/latest/meta-data/placement/availability-zone",