Annotate twitter errors to make creating better alerts possible (#49)

service/adapters/prometheus/prometheus.go

@@ -1,11 +1,13 @@
 package prometheus
 
 import (
+	"fmt"
 	"runtime/debug"
 	"time"
 
 	"github.com/boreq/errors"
 	"github.com/planetary-social/nos-crossposting-service/internal/logging"
+	"github.com/planetary-social/nos-crossposting-service/service/adapters/twitter"
 	"github.com/planetary-social/nos-crossposting-service/service/app"
 	"github.com/planetary-social/nos-crossposting-service/service/domain"
 	"github.com/planetary-social/nos-crossposting-service/service/domain/accounts"
@@ -32,6 +34,8 @@ const (
 	labelResultValueError                = "error"
 	labelResultValueInvalidPointerPassed = "invalidPointerPassed"
 
+	labelErrorDescription = "errorDescription"
+
 	labelAction               = "action"
 	labelActionValuePostTweet = "postTweet"
 	labelActionValueGetUser   = "getUser"
@@ -64,14 +68,14 @@ func NewPrometheus(logger logging.Logger) (*Prometheus, error) {
 			Name: "application_handler_calls_total",
 			Help: "Total number of calls to application handlers.",
 		},
-		[]string{labelHandlerName, labelResult},
+		[]string{labelHandlerName, labelResult, labelErrorDescription},
 	)
 	applicationHandlerCallDurationHistogram := prometheus.NewHistogramVec(
 		prometheus.HistogramOpts{
 			Name: "application_handler_calls_duration",
 			Help: "Duration of calls to application handlers in seconds.",
 		},
-		[]string{labelHandlerName, labelResult},
+		[]string{labelHandlerName, labelResult, labelErrorDescription},
 	)
 	subscriptionQueueLengthGauge := prometheus.NewGaugeVec(
 		prometheus.GaugeOpts{
@@ -112,7 +116,7 @@ func NewPrometheus(logger logging.Logger) (*Prometheus, error) {
 			Name: "twitter_api_calls",
 			Help: "Total number of calls to Twitter API to post tweets.",
 		},
-		[]string{labelResult, labelAction},
+		[]string{labelResult, labelAction, labelErrorDescription},
 	)
 	purplePagesLookupResultCounter := prometheus.NewCounterVec(
 		prometheus.CounterOpts{
@@ -224,7 +228,8 @@ func (p *Prometheus) ReportRelayConnectionState(m map[domain.RelayAddress]app.Re
 
 func (p *Prometheus) ReportCallingTwitterAPIToPostATweet(err error) {
 	labels := prometheus.Labels{
-		labelAction: labelActionValuePostTweet,
+		labelAction:           labelActionValuePostTweet,
+		labelErrorDescription: p.getTwitterErrorDescription(err),
 	}
 	if err == nil {
 		labels[labelResult] = labelResultValueSuccess
@@ -236,7 +241,8 @@ func (p *Prometheus) ReportCallingTwitterAPIToPostATweet(err error) {
 
 func (p *Prometheus) ReportCallingTwitterAPIToGetAUser(err error) {
 	labels := prometheus.Labels{
-		labelAction: labelActionValueGetUser,
+		labelAction:           labelActionValueGetUser,
+		labelErrorDescription: p.getTwitterErrorDescription(err),
 	}
 	if err == nil {
 		labels[labelResult] = labelResultValueSuccess
@@ -278,6 +284,19 @@ func (p *Prometheus) ReportNumberOfLinkedPublicKeys(count int) {
 	p.numberOfLinkedPublicKeysGauge.Set(float64(count))
 }
 
+func (p *Prometheus) getTwitterErrorDescription(err error) string {
+	if err == nil {
+		return "none"
+	}
+
+	var twitterError twitter.TwitterError
+	if errors.As(err, &twitterError) {
+		return fmt.Sprintf("twitter/%s", twitterError.Description())
+	}
+
+	return "unknown"
+}
+
 type ApplicationCall struct {
 	handlerName string
 	p           *Prometheus
@@ -319,13 +338,31 @@ func (a *ApplicationCall) getLabels(err *error) prometheus.Labels {
 
 	if err == nil {
 		labels[labelResult] = labelResultValueInvalidPointerPassed
+		labels[labelErrorDescription] = "invalidPointer"
 	} else {
 		if *err == nil {
 			labels[labelResult] = labelResultValueSuccess
 		} else {
 			labels[labelResult] = labelResultValueError
 		}
+		labels[labelErrorDescription] = a.getErrorDescription(*err)
 	}
 
 	return labels
 }
+
+func (a *ApplicationCall) getErrorDescription(err error) string {
+	if err == nil {
+		return "none"
+	}
+
+	if errors.Is(err, twitter.ErrExceededLimiterLimit) {
+		return "twitter/limiter"
+	}
+
+	if errors.Is(err, twitter.TwitterError{}) {
+		return "twitter/error"
+	}
+
+	return "unknown"
+}

service/adapters/twitter/limiter.go

@@ -6,6 +6,8 @@ import (
 	"github.com/boreq/errors"
 )
 
+var ErrExceededLimiterLimit = errors.New("exceeded the limit in limiter")
+
 type Limiter struct {
 	m map[string][]time.Time
 }
@@ -24,7 +26,7 @@ func (l *Limiter) Limit(key string, number int, window time.Duration) error {
 	}
 
 	if len(l.m[key]) > number {
-		return errors.New("exceeded the limit")
+		return ErrExceededLimiterLimit
 	}
 
 	l.m[key] = append(l.m[key], time.Now())

service/adapters/twitter/twitter.go

@@ -72,6 +72,7 @@ func (t *Twitter) PostTweet(
 	response, err := client.CreateTweet(ctx, twitter.CreateTweetRequest{
 		Text: tweet.Text(),
 	})
+	err = t.convertError(err)
 	t.metrics.ReportCallingTwitterAPIToPostATweet(err)
 	if err != nil {
 		t.logError(err)
@@ -120,6 +121,7 @@ func (t *Twitter) GetAccountDetails(
 			twitter.UserFieldProfileImageURL,
 		},
 	})
+	err = t.convertError(err)
 	t.metrics.ReportCallingTwitterAPIToGetAUser(err)
 	if err != nil {
 		t.logError(err)
@@ -159,6 +161,19 @@ func (t *Twitter) logError(err error) {
 	}
 }
 
+func (t *Twitter) convertError(err error) error {
+	if err == nil {
+		return nil
+	}
+
+	var errorResponse *twitter.ErrorResponse
+	if errors.As(err, &errorResponse) {
+		return NewTwitterError(errorResponse)
+	}
+
+	return err
+}
+
 type userAuthorizer struct {
 	conf             config.Config
 	userAccessToken  accounts.TwitterUserAccessToken
@@ -195,3 +210,29 @@ func (a *userAuthorizer) Add(req *http.Request) {
 	authHeader := auth.BuildOAuth1Header(req.Method, req.URL.String(), a.params)
 	req.Header.Set("Authorization", authHeader)
 }
+
+type TwitterError struct {
+	underlying *twitter.ErrorResponse
+}
+
+func NewTwitterError(underlying *twitter.ErrorResponse) TwitterError {
+	return TwitterError{underlying: underlying}
+}
+
+func (t TwitterError) Error() string {
+	return fmt.Sprintf("twitter error: %s", t.underlying)
+}
+
+func (t TwitterError) Unwrap() error {
+	return t.underlying
+}
+
+func (t TwitterError) Description() string {
+	return t.underlying.Title
+}
+
+func (t TwitterError) Is(target error) bool {
+	_, ok1 := target.(TwitterError)
+	_, ok2 := target.(*TwitterError)
+	return ok1 || ok2
+}

service/adapters/twitter/twitter_test.go

@@ -0,0 +1,19 @@
+package twitter_test
+
+import (
+	"testing"
+
+	"github.com/boreq/errors"
+	twitterlib "github.com/g8rswimmer/go-twitter/v2"
+	"github.com/planetary-social/nos-crossposting-service/service/adapters/twitter"
+	"github.com/stretchr/testify/require"
+)
+
+func TestErrorIs(t *testing.T) {
+	someError := &twitterlib.ErrorResponse{}
+	err := twitter.NewTwitterError(someError)
+	require.ErrorIs(t, err, twitter.TwitterError{})
+	require.ErrorIs(t, err, &twitter.TwitterError{})
+	require.ErrorIs(t, errors.Wrap(err, "wrapped"), twitter.TwitterError{})
+	require.ErrorIs(t, errors.Wrap(err, "wrapped"), &twitter.TwitterError{})
+}