Use the correct default for aws_auth.service for the AWS PRW exporter (…

…#3161)

* Use the correct default for aws_auth.region for the AWS PRW exporter

"aps" is currently the only value that is acceptable for this field. We should have never provided it as a configuration setting but we can't remove and break the existing users. This change is setting it to "aps" by default.

A follow up change will be provided to automatically parse the region from the workspace remote write endpoint.

* Reorder

* Improve godoc

exporter/awsprometheusremotewriteexporter/README.md

@@ -61,6 +61,7 @@ exporters:
     endpoint: "https://aps-workspaces.us-east-1.amazonaws.com/workspaces/ws-XXX/api/v1/remote_write"
     aws_auth:
         region: "us-east-1" # need to match workspace region
+        service: "aps"
         role_arn: "arn:aws:iam::123456789012:role/aws-service-role/access"
     ca_file: "/var/lib/mycert.pem"
     write_buffer_size: 524288

exporter/awsprometheusremotewriteexporter/auth.go

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package awsprometheusremotewriteexporter provides a Prometheus Remote Write Exporter with AWS Sigv4 authentication
 package awsprometheusremotewriteexporter
 
 import (
@@ -30,40 +29,37 @@ import (
 	v4 "github.com/aws/aws-sdk-go/aws/signer/v4"
 )
 
-// signingRoundTripper is a Custom RoundTripper that performs AWS Sig V4
+const defaultAMPSigV4Service = "aps"
+
+// signingRoundTripper is a Custom RoundTripper that performs AWS Sig V4.
 type signingRoundTripper struct {
 	transport http.RoundTripper
 	signer    *v4.Signer
 	region    string
 	service   string
 }
 
-// RoundTrip signs each outgoing request
 func (si *signingRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
 	reqBody, err := req.GetBody()
 	if err != nil {
 		return nil, err
 	}
 
-	// Get the body
 	content, err := ioutil.ReadAll(reqBody)
 	reqBody.Close()
 	if err != nil {
 		return nil, err
 	}
-
 	body := bytes.NewReader(content)
 
-	// Clone request to ensure thread safety
+	// Clone request to ensure thread safety.
 	req2 := cloneRequest(req)
-
-	// Sign the request
 	_, err = si.signer.Sign(req2, body, si.service, si.region, time.Now())
 	if err != nil {
 		return nil, err
 	}
 
-	// Send the request to Prometheus Remote Write Backend
+	// Send the request to Prometheus Remote Write Backend.
 	resp, err := si.transport.RoundTrip(req2)
 	if err != nil {
 		return nil, err
@@ -73,14 +69,20 @@ func (si *signingRoundTripper) RoundTrip(req *http.Request) (*http.Response, err
 }
 
 func newSigningRoundTripper(auth AuthConfig, next http.RoundTripper) (http.RoundTripper, error) {
+	if auth.Region == "" {
+		// TODO(jbd): Automatically parse the region from the workspace.
+		return next, nil
+	}
+	if auth.Service == "" {
+		auth.Service = defaultAMPSigV4Service
+	}
 
 	creds := getCredsFromConfig(auth)
-	return createSigningRoundTripperWithCredentials(auth, creds, next)
+	return newSigningRoundTripperWithCredentials(auth, creds, next)
 }
 
 func getCredsFromConfig(auth AuthConfig) *credentials.Credentials {
-
-	// Session Must ensure the Session is valid
+	// TODO: Don't panic, handle the error from NewSessionWithOptions.
 	sess := session.Must(session.NewSessionWithOptions(session.Options{
 		Config: aws.Config{Region: aws.String(auth.Region)},
 	}))
@@ -98,32 +100,20 @@ func getCredsFromConfig(auth AuthConfig) *credentials.Credentials {
 	return creds
 }
 
-func createSigningRoundTripperWithCredentials(auth AuthConfig, creds *credentials.Credentials, next http.RoundTripper) (http.RoundTripper, error) {
-	if !isValidAuth(auth) {
-		return next, nil
-	}
-
+func newSigningRoundTripperWithCredentials(auth AuthConfig, creds *credentials.Credentials, next http.RoundTripper) (http.RoundTripper, error) {
 	if creds == nil {
 		return nil, errors.New("no AWS credentials exist")
 	}
-
 	signer := v4.NewSigner(creds)
-
 	rt := signingRoundTripper{
 		transport: next,
 		signer:    signer,
 		region:    auth.Region,
 		service:   auth.Service,
 	}
-
-	// return a RoundTripper
 	return &rt, nil
 }
 
-func isValidAuth(params AuthConfig) bool {
-	return params.Region != "" && params.Service != ""
-}
-
 func cloneRequest(r *http.Request) *http.Request {
 	// shallow copy of the struct
 	r2 := new(http.Request)

exporter/awsprometheusremotewriteexporter/auth_test.go

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package awsprometheusremotewriteexporter provides a Prometheus Remote Write Exporter with AWS Sigv4 authentication
 package awsprometheusremotewriteexporter
 
 import (
@@ -55,7 +54,7 @@ func TestRequestSignature(t *testing.T) {
 		WriteBufferSize: 0,
 		Timeout:         0,
 		CustomRoundTripper: func(next http.RoundTripper) (http.RoundTripper, error) {
-			return createSigningRoundTripperWithCredentials(authConfig, awsCreds, next)
+			return newSigningRoundTripperWithCredentials(authConfig, awsCreds, next)
 		},
 	}
 	client, _ := setting.ToClient()
@@ -100,7 +99,7 @@ func TestLeakingBody(t *testing.T) {
 		WriteBufferSize: 0,
 		Timeout:         0,
 		CustomRoundTripper: func(next http.RoundTripper) (http.RoundTripper, error) {
-			return createSigningRoundTripperWithCredentials(authConfig, awsCreds, next)
+			return newSigningRoundTripperWithCredentials(authConfig, awsCreds, next)
 		},
 	}
 	client, _ := setting.ToClient()
@@ -184,7 +183,7 @@ func TestRoundTrip(t *testing.T) {
 			defer server.Close()
 			serverURL, _ := url.Parse(server.URL)
 			authConfig := AuthConfig{Region: "region", Service: "service"}
-			rt, err := createSigningRoundTripperWithCredentials(authConfig, awsCreds, tt.rt)
+			rt, err := newSigningRoundTripperWithCredentials(authConfig, awsCreds, tt.rt)
 			assert.NoError(t, err)
 			req, err := http.NewRequest("POST", serverURL.String(), strings.NewReader(""))
 			assert.NoError(t, err)
@@ -201,7 +200,6 @@ func TestRoundTrip(t *testing.T) {
 }
 
 func TestCreateSigningRoundTripperWithCredentials(t *testing.T) {
-
 	defaultRoundTripper := (http.RoundTripper)(http.DefaultTransport.(*http.Transport).Clone())
 
 	// Some form of AWS credentials must be set up for tests to succeed
@@ -240,10 +238,9 @@ func TestCreateSigningRoundTripperWithCredentials(t *testing.T) {
 			true,
 		},
 	}
-	// run tests
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			rtp, err := createSigningRoundTripperWithCredentials(tt.authConfig, tt.creds, tt.roundTripper)
+			rtp, err := newSigningRoundTripperWithCredentials(tt.authConfig, tt.creds, tt.roundTripper)
 			if tt.returnError {
 				assert.Error(t, err)
 				return
@@ -253,8 +250,6 @@ func TestCreateSigningRoundTripperWithCredentials(t *testing.T) {
 				sRtp := rtp.(*signingRoundTripper)
 				assert.Equal(t, sRtp.transport, tt.roundTripper)
 				assert.Equal(t, tt.authConfig.Service, sRtp.service)
-			} else {
-				assert.Equal(t, rtp, tt.roundTripper)
 			}
 		})
 	}
@@ -294,7 +289,9 @@ func TestCloneRequest(t *testing.T) {
 }
 
 func fetchMockCredentials() *credentials.Credentials {
-	return credentials.NewStaticCredentials("MOCK_AWS_ACCESS_KEY",
+	return credentials.NewStaticCredentials(
+		"MOCK_AWS_ACCESS_KEY",
 		"MOCK_AWS_SECRET_ACCESS_KEY",
-		"MOCK_TOKEN")
+		"MOCK_TOKEN",
+	)
 }

exporter/awsprometheusremotewriteexporter/config.go

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package awsprometheusremotewriteexporter provides a Prometheus Remote Write Exporter with AWS Sigv4 authentication
 package awsprometheusremotewriteexporter
 
 import (
@@ -21,19 +20,21 @@ import (
 
 // Config defines configuration for Remote Write exporter.
 type Config struct {
-	// Config represents the Prometheus Remote Write Exporter configuration
+	// Config represents the Prometheus Remote Write Exporter configuration.
 	prw.Config `mapstructure:",squash"`
 
-	// AuthConfig represents the AWS Sig V4 configuration options
+	// AuthConfig represents the AWS SigV4 configuration options.
 	AuthConfig AuthConfig `mapstructure:"aws_auth"`
 }
 
-// AuthConfig defines AWS authentication configurations for SigningRoundTripper
+// AuthConfig defines AWS authentication configurations for SigningRoundTripper.
 type AuthConfig struct {
-	// Region is the AWS region for AWS Sig v4.
+	// Region is the AWS region for AWS SigV4.
 	Region string `mapstructure:"region"`
-	// Service is the service name for AWS Sig v4
+
+	// Service is the AWS service for AWS SigV4, this is by default "aps". Optional.
 	Service string `mapstructure:"service"`
-	// Amazon Resource Name (ARN) of a role to assume
+
+	// Amazon Resource Name (ARN) of a role to assume. Optional.
 	RoleArn string `mapstructure:"role_arn"`
 }

exporter/awsprometheusremotewriteexporter/config_test.go

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package awsprometheusremotewriteexporter provides a Prometheus Remote Write Exporter with AWS Sigv4 authentication
 package awsprometheusremotewriteexporter
 
 import (
@@ -31,7 +30,7 @@ import (
 	prw "go.opentelemetry.io/collector/exporter/prometheusremotewriteexporter"
 )
 
-// TestLoadConfig checks whether yaml configuration can be loaded correctly
+// TestLoadConfig checks whether yaml configuration can be loaded correctly.
 func TestLoadConfig(t *testing.T) {
 	factories, err := componenttest.NopFactories()
 	assert.NoError(t, err)

exporter/awsprometheusremotewriteexporter/factory.go

@@ -17,7 +17,6 @@ package awsprometheusremotewriteexporter
 
 import (
 	"context"
-	"errors"
 	"net/http"
 
 	"go.opentelemetry.io/collector/component"
@@ -50,25 +49,16 @@ func (af *awsFactory) CreateDefaultConfig() config.Exporter {
 		Config: *af.ExporterFactory.CreateDefaultConfig().(*prw.Config),
 		AuthConfig: AuthConfig{
 			Region:  "",
-			Service: "",
+			Service: defaultAMPSigV4Service,
 			RoleArn: "",
 		},
 	}
 
 	cfg.TypeVal = typeStr
 	cfg.NameVal = typeStr
-
 	cfg.HTTPClientSettings.CustomRoundTripper = func(next http.RoundTripper) (http.RoundTripper, error) {
-		if !isAuthConfigValid(cfg.AuthConfig) {
-			return nil, errors.New("invalid authentication configuration")
-		}
-
 		return newSigningRoundTripper(cfg.AuthConfig, next)
 	}
 
 	return cfg
 }
-
-func isAuthConfigValid(params AuthConfig) bool {
-	return !(params.Region != "" && params.Service == "" || params.Region == "" && params.Service != "")
-}

exporter/awsprometheusremotewriteexporter/factory_test.go

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package awsprometheusremotewriteexporter provides a Prometheus Remote Write Exporter with AWS Sigv4 authentication
 package awsprometheusremotewriteexporter
 
 import (
@@ -87,11 +86,6 @@ func TestCreateMetricsExporter(t *testing.T) {
 			component.ExporterCreateParams{Logger: zap.NewNop()},
 			false,
 		},
-		{"invalid_auth_case",
-			invalidConfigWithAuth,
-			component.ExporterCreateParams{Logger: zap.NewNop()},
-			true,
-		},
 		{"invalid_config_case",
 			invalidConfig,
 			component.ExporterCreateParams{Logger: zap.NewNop()},