Read the "standard" AWS environment variables

This is 100% backwards-compatible

builtin/providers/aws/provider.go

@@ -15,21 +15,30 @@ func Provider() terraform.ResourceProvider {
 			"access_key": &schema.Schema{
 				Type:     schema.TypeString,
 				Required: true,
-				DefaultFunc: schema.EnvDefaultFunc("AWS_ACCESS_KEY", nil),
+				DefaultFunc: schema.MultiEnvDefaultFunc([]string{
+					"AWS_ACCESS_KEY",
+					"AWS_ACCESS_KEY_ID",
+				}, nil),
 				Description: descriptions["access_key"],
 			},
 
 			"secret_key": &schema.Schema{
 				Type:     schema.TypeString,
 				Required: true,
-				DefaultFunc: schema.EnvDefaultFunc("AWS_SECRET_KEY", nil),
+				DefaultFunc: schema.MultiEnvDefaultFunc([]string{
+					"AWS_SECRET_KEY",
+					"AWS_SECRET_ACCESS_KEY",
+				}, nil),
 				Description: descriptions["secret_key"],
 			},
 
 			"region": &schema.Schema{
 				Type:     schema.TypeString,
 				Required: true,
-				DefaultFunc:  schema.EnvDefaultFunc("AWS_REGION", nil),
+				DefaultFunc: schema.MultiEnvDefaultFunc([]string{
+					"AWS_REGION",
+					"AWS_DEFAULT_REGION",
+				}, nil),
 				Description:  descriptions["region"],
 				InputDefault: "us-east-1",
 			},

builtin/providers/aws/provider_test.go

@@ -30,14 +30,14 @@ func TestProvider_impl(t *testing.T) {
 }
 
 func testAccPreCheck(t *testing.T) {
-	if v := os.Getenv("AWS_ACCESS_KEY"); v == "" {
-		t.Fatal("AWS_ACCESS_KEY must be set for acceptance tests")
+	if v := os.Getenv("AWS_ACCESS_KEY_ID"); v == "" {
+		t.Fatal("AWS_ACCESS_KEY_ID must be set for acceptance tests")
 	}
-	if v := os.Getenv("AWS_SECRET_KEY"); v == "" {
-		t.Fatal("AWS_SECRET_KEY must be set for acceptance tests")
+	if v := os.Getenv("AWS_SECRET_ACCESS_KEY"); v == "" {
+		t.Fatal("AWS_SECRET_ACCESS_KEY must be set for acceptance tests")
 	}
-	if v := os.Getenv("AWS_REGION"); v == "" {
+	if v := os.Getenv("AWS_DEFAULT_REGION"); v == "" {
 		log.Println("[INFO] Test: Using us-west-2 as test region")
-		os.Setenv("AWS_REGION", "us-west-2")
+		os.Setenv("AWS_DEFAULT_REGION", "us-west-2")
 	}
 }

helper/schema/schema.go

@@ -174,6 +174,21 @@ func EnvDefaultFunc(k string, dv interface{}) SchemaDefaultFunc {
 	}
 }
 
+// MultiEnvDefaultFunc is a helper function that returns the value of the first
+// environment variable in the given list that returns a non-empty value. If
+// none of the environment variables return a value, the default value is
+// returned.
+func MultiEnvDefaultFunc(ks []string, dv interface{}) SchemaDefaultFunc {
+	return func() (interface{}, error) {
+		for _, k := range ks {
+			if v := os.Getenv(k); v != "" {
+				return v, nil
+			}
+		}
+		return dv, nil
+	}
+}
+
 // SchemaSetFunc is a function that must return a unique ID for the given
 // element. This unique ID is used to store the element in a hash.
 type SchemaSetFunc func(interface{}) int

helper/schema/schema_test.go

@@ -40,6 +40,43 @@ func TestEnvDefaultFunc(t *testing.T) {
 	}
 }
 
+func TestMultiEnvDefaultFunc(t *testing.T) {
+	keys := []string{
+		"TF_TEST_MULTI_ENV_DEFAULT_FUNC1",
+		"TF_TEST_MULTI_ENV_DEFAULT_FUNC2",
+	}
+	defer func() {
+		for _, k := range keys {
+			os.Unsetenv(k)
+		}
+	}()
+
+	f := MultiEnvDefaultFunc(keys, "42")
+	if err := os.Setenv(keys[1], "foo"); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual, err := f()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if actual != "foo" {
+		t.Fatalf("bad: %#v", actual)
+	}
+
+	if err := os.Unsetenv(keys[1]); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual, err = f()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if actual != "42" {
+		t.Fatalf("bad: %#v", actual)
+	}
+}
+
 func TestValueType_Zero(t *testing.T) {
 	cases := []struct {
 		Type  ValueType