Merge pull request #10857 from pstibrany/fix-errors-handling

API: Fix errors handling

web/api/v1/api.go

@@ -553,7 +553,12 @@ func returnAPIError(err error) *apiError {
 		return nil
 	}
 
-	switch errors.Cause(err).(type) {
+	cause := errors.Unwrap(err)
+	if cause == nil {
+		cause = err
+	}
+
+	switch cause.(type) {
 	case promql.ErrQueryCanceled:
 		return &apiError{errorCanceled, err}
 	case promql.ErrQueryTimeout:

web/api/v1/api_test.go

@@ -2948,30 +2948,30 @@ func TestReturnAPIError(t *testing.T) {
 			err:      promql.ErrStorage{Err: errors.New("storage error")},
 			expected: errorInternal,
 		}, {
-			err:      errors.Wrap(promql.ErrStorage{Err: errors.New("storage error")}, "wrapped"),
+			err:      fmt.Errorf("wrapped: %w", promql.ErrStorage{Err: errors.New("storage error")}),
 			expected: errorInternal,
 		}, {
 			err:      promql.ErrQueryTimeout("timeout error"),
 			expected: errorTimeout,
 		}, {
-			err:      errors.Wrap(promql.ErrQueryTimeout("timeout error"), "wrapped"),
+			err:      fmt.Errorf("wrapped: %w", promql.ErrQueryTimeout("timeout error")),
 			expected: errorTimeout,
 		}, {
 			err:      promql.ErrQueryCanceled("canceled error"),
 			expected: errorCanceled,
 		}, {
-			err:      errors.Wrap(promql.ErrQueryCanceled("canceled error"), "wrapped"),
+			err:      fmt.Errorf("wrapped: %w", promql.ErrQueryCanceled("canceled error")),
 			expected: errorCanceled,
 		}, {
 			err:      errors.New("exec error"),
 			expected: errorExec,
 		},
 	}
 
-	for _, c := range cases {
+	for ix, c := range cases {
 		actual := returnAPIError(c.err)
-		require.Error(t, actual)
-		require.Equal(t, c.expected, actual.typ)
+		require.Error(t, actual, ix)
+		require.Equal(t, c.expected, actual.typ, ix)
 	}
 }
 

web/api/v1/errors_test.go

@@ -0,0 +1,236 @@
+// Copyright 2022 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v1
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+	"time"
+
+	"github.com/go-kit/log"
+	"github.com/grafana/regexp"
+	"github.com/pkg/errors"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/route"
+	"github.com/stretchr/testify/require"
+
+	"github.com/prometheus/prometheus/config"
+	"github.com/prometheus/prometheus/model/labels"
+	"github.com/prometheus/prometheus/promql"
+	"github.com/prometheus/prometheus/rules"
+	"github.com/prometheus/prometheus/scrape"
+	"github.com/prometheus/prometheus/storage"
+)
+
+func TestApiStatusCodes(t *testing.T) {
+	for name, tc := range map[string]struct {
+		err            error
+		expectedString string
+		expectedCode   int
+	}{
+		"random error": {
+			err:            errors.New("some random error"),
+			expectedString: "some random error",
+			expectedCode:   http.StatusUnprocessableEntity,
+		},
+
+		"promql.ErrTooManySamples": {
+			err:            promql.ErrTooManySamples("some error"),
+			expectedString: "too many samples",
+			expectedCode:   http.StatusUnprocessableEntity,
+		},
+
+		"promql.ErrQueryCanceled": {
+			err:            promql.ErrQueryCanceled("some error"),
+			expectedString: "query was canceled",
+			expectedCode:   http.StatusServiceUnavailable,
+		},
+
+		"promql.ErrQueryTimeout": {
+			err:            promql.ErrQueryTimeout("some error"),
+			expectedString: "query timed out",
+			expectedCode:   http.StatusServiceUnavailable,
+		},
+
+		"context.DeadlineExceeded": {
+			err:            context.DeadlineExceeded,
+			expectedString: "context deadline exceeded",
+			expectedCode:   http.StatusUnprocessableEntity,
+		},
+
+		"context.Canceled": {
+			err:            context.Canceled,
+			expectedString: "context canceled",
+			expectedCode:   http.StatusUnprocessableEntity,
+		},
+	} {
+		for k, q := range map[string]storage.SampleAndChunkQueryable{
+			"error from queryable": errorTestQueryable{err: tc.err},
+			"error from querier":   errorTestQueryable{q: errorTestQuerier{err: tc.err}},
+			"error from seriesset": errorTestQueryable{q: errorTestQuerier{s: errorTestSeriesSet{err: tc.err}}},
+		} {
+			t.Run(fmt.Sprintf("%s/%s", name, k), func(t *testing.T) {
+				r := createPrometheusAPI(q)
+				rec := httptest.NewRecorder()
+
+				req := httptest.NewRequest("GET", "/api/v1/query?query=up", nil)
+
+				r.ServeHTTP(rec, req)
+
+				require.Equal(t, tc.expectedCode, rec.Code)
+				require.Contains(t, rec.Body.String(), tc.expectedString)
+			})
+		}
+	}
+}
+
+func createPrometheusAPI(q storage.SampleAndChunkQueryable) *route.Router {
+	engine := promql.NewEngine(promql.EngineOpts{
+		Logger:             log.NewNopLogger(),
+		Reg:                nil,
+		ActiveQueryTracker: nil,
+		MaxSamples:         100,
+		Timeout:            5 * time.Second,
+	})
+
+	api := NewAPI(
+		engine,
+		q,
+		nil,
+		nil,
+		func(context.Context) TargetRetriever { return &DummyTargetRetriever{} },
+		func(context.Context) AlertmanagerRetriever { return &DummyAlertmanagerRetriever{} },
+		func() config.Config { return config.Config{} },
+		map[string]string{}, // TODO: include configuration flags
+		GlobalURLOptions{},
+		func(f http.HandlerFunc) http.HandlerFunc { return f },
+		nil,   // Only needed for admin APIs.
+		"",    // This is for snapshots, which is disabled when admin APIs are disabled. Hence empty.
+		false, // Disable admin APIs.
+		log.NewNopLogger(),
+		func(context.Context) RulesRetriever { return &DummyRulesRetriever{} },
+		0, 0, 0, // Remote read samples and concurrency limit.
+		false, // Not an agent.
+		regexp.MustCompile(".*"),
+		func() (RuntimeInfo, error) { return RuntimeInfo{}, errors.New("not implemented") },
+		&PrometheusVersion{},
+		prometheus.DefaultGatherer,
+		nil,
+		nil,
+	)
+
+	promRouter := route.New().WithPrefix("/api/v1")
+	api.Register(promRouter)
+
+	return promRouter
+}
+
+type errorTestQueryable struct {
+	q   storage.Querier
+	err error
+}
+
+func (t errorTestQueryable) ChunkQuerier(ctx context.Context, mint, maxt int64) (storage.ChunkQuerier, error) {
+	return nil, t.err
+}
+
+func (t errorTestQueryable) Querier(ctx context.Context, mint, maxt int64) (storage.Querier, error) {
+	if t.q != nil {
+		return t.q, nil
+	}
+	return nil, t.err
+}
+
+type errorTestQuerier struct {
+	s   storage.SeriesSet
+	err error
+}
+
+func (t errorTestQuerier) LabelValues(name string, matchers ...*labels.Matcher) ([]string, storage.Warnings, error) {
+	return nil, nil, t.err
+}
+
+func (t errorTestQuerier) LabelNames(matchers ...*labels.Matcher) ([]string, storage.Warnings, error) {
+	return nil, nil, t.err
+}
+
+func (t errorTestQuerier) Close() error {
+	return nil
+}
+
+func (t errorTestQuerier) Select(sortSeries bool, hints *storage.SelectHints, matchers ...*labels.Matcher) storage.SeriesSet {
+	if t.s != nil {
+		return t.s
+	}
+	return storage.ErrSeriesSet(t.err)
+}
+
+type errorTestSeriesSet struct {
+	err error
+}
+
+func (t errorTestSeriesSet) Next() bool {
+	return false
+}
+
+func (t errorTestSeriesSet) At() storage.Series {
+	return nil
+}
+
+func (t errorTestSeriesSet) Err() error {
+	return t.err
+}
+
+func (t errorTestSeriesSet) Warnings() storage.Warnings {
+	return nil
+}
+
+// DummyTargetRetriever implements github.com/prometheus/prometheus/web/api/v1.targetRetriever.
+type DummyTargetRetriever struct{}
+
+// TargetsActive implements targetRetriever.
+func (DummyTargetRetriever) TargetsActive() map[string][]*scrape.Target {
+	return map[string][]*scrape.Target{}
+}
+
+// TargetsDropped implements targetRetriever.
+func (DummyTargetRetriever) TargetsDropped() map[string][]*scrape.Target {
+	return map[string][]*scrape.Target{}
+}
+
+// DummyAlertmanagerRetriever implements AlertmanagerRetriever.
+type DummyAlertmanagerRetriever struct{}
+
+// Alertmanagers implements AlertmanagerRetriever.
+func (DummyAlertmanagerRetriever) Alertmanagers() []*url.URL { return nil }
+
+// DroppedAlertmanagers implements AlertmanagerRetriever.
+func (DummyAlertmanagerRetriever) DroppedAlertmanagers() []*url.URL { return nil }
+
+// DummyRulesRetriever implements RulesRetriever.
+type DummyRulesRetriever struct{}
+
+// RuleGroups implements RulesRetriever.
+func (DummyRulesRetriever) RuleGroups() []*rules.Group {
+	return nil
+}
+
+// AlertingRules implements RulesRetriever.
+func (DummyRulesRetriever) AlertingRules() []*rules.AlertingRule {
+	return nil
+}