From 3e94dd8c8f83a11c4ac30e5a748b96adbc85cb40 Mon Sep 17 00:00:00 2001 From: Charles Korn Date: Wed, 25 Jan 2023 14:30:47 +1100 Subject: [PATCH] Add extension point for returning different content types from API endpoints Signed-off-by: Charles Korn --- web/api/v1/api.go | 64 ++++++-- web/api/v1/api_test.go | 290 ++++++++++++---------------------- web/api/v1/codec.go | 26 +++ web/api/v1/json_codec.go | 32 ++++ web/api/v1/json_codec_test.go | 178 +++++++++++++++++++++ 5 files changed, 391 insertions(+), 199 deletions(-) create mode 100644 web/api/v1/codec.go create mode 100644 web/api/v1/json_codec.go create mode 100644 web/api/v1/json_codec_test.go diff --git a/web/api/v1/api.go b/web/api/v1/api.go index 894a8666a6..525bc446ae 100644 --- a/web/api/v1/api.go +++ b/web/api/v1/api.go @@ -80,6 +80,8 @@ const ( var LocalhostRepresentations = []string{"127.0.0.1", "localhost", "::1"} +var defaultCodec = JSONCodec{} + type apiError struct { typ errorType err error @@ -145,7 +147,8 @@ type RuntimeInfo struct { StorageRetention string `json:"storageRetention"` } -type response struct { +// Response contains a response to a HTTP API request. +type Response struct { Status status `json:"status"` Data interface{} `json:"data,omitempty"` ErrorType errorType `json:"errorType,omitempty"` @@ -208,6 +211,8 @@ type API struct { remoteWriteHandler http.Handler remoteReadHandler http.Handler + + codecs map[string]Codec } func init() { @@ -273,8 +278,12 @@ func NewAPI( statsRenderer: defaultStatsRenderer, remoteReadHandler: remote.NewReadHandler(logger, registerer, q, configFunc, remoteReadSampleLimit, remoteReadConcurrencyLimit, remoteReadMaxBytesInFrame), + + codecs: map[string]Codec{}, } + a.InstallCodec(defaultCodec) + if statsRenderer != nil { a.statsRenderer = statsRenderer } @@ -286,6 +295,16 @@ func NewAPI( return a } +// InstallCodec adds codec to this API's available codecs. +// If codec handles a content type handled by a codec already installed in this API, codec replaces the previous codec. +func (api *API) InstallCodec(codec Codec) { + if api.codecs == nil { + api.codecs = map[string]Codec{} + } + + api.codecs[codec.ContentType()] = codec +} + func setUnavailStatusOnTSDBNotReady(r apiFuncResult) apiFuncResult { if r.err != nil && errors.Cause(r.err.err) == tsdb.ErrNotReady { r.err.typ = errorUnavailable @@ -308,7 +327,7 @@ func (api *API) Register(r *route.Router) { } if result.data != nil { - api.respond(w, result.data, result.warnings) + api.respond(w, r, result.data, result.warnings) return } w.WriteHeader(http.StatusNoContent) @@ -1446,7 +1465,7 @@ func (api *API) serveWALReplayStatus(w http.ResponseWriter, r *http.Request) { if err != nil { api.respondError(w, &apiError{errorInternal, err}, nil) } - api.respond(w, walReplayStatus{ + api.respond(w, r, walReplayStatus{ Min: status.Min, Max: status.Max, Current: status.Current, @@ -1548,34 +1567,59 @@ func (api *API) cleanTombstones(r *http.Request) apiFuncResult { return apiFuncResult{nil, nil, nil, nil} } -func (api *API) respond(w http.ResponseWriter, data interface{}, warnings storage.Warnings) { +func (api *API) respond(w http.ResponseWriter, req *http.Request, data interface{}, warnings storage.Warnings) { statusMessage := statusSuccess var warningStrings []string for _, warning := range warnings { warningStrings = append(warningStrings, warning.Error()) } - json := jsoniter.ConfigCompatibleWithStandardLibrary - b, err := json.Marshal(&response{ + + resp := &Response{ Status: statusMessage, Data: data, Warnings: warningStrings, - }) + } + + codec := api.negotiateCodec(req, resp) + b, err := codec.Encode(resp) if err != nil { - level.Error(api.logger).Log("msg", "error marshaling json response", "err", err) + level.Error(api.logger).Log("msg", "error marshaling response", "err", err) http.Error(w, err.Error(), http.StatusInternalServerError) return } - w.Header().Set("Content-Type", "application/json") + w.Header().Set("Content-Type", codec.ContentType()) w.WriteHeader(http.StatusOK) if n, err := w.Write(b); err != nil { level.Error(api.logger).Log("msg", "error writing response", "bytesWritten", n, "err", err) } } +// HTTP content negotiation is hard (see https://developer.mozilla.org/en-US/docs/Web/HTTP/Content_negotiation). +// Ideally, we shouldn't be implementing this ourselves - https://github.com/golang/go/issues/19307 is an open proposal to add +// this to the Go stdlib and has links to a number of other implementations. +// +// This is an MVP, and doesn't support features like wildcards or weighting. +func (api *API) negotiateCodec(req *http.Request, resp *Response) Codec { + acceptHeader := req.Header.Get("Accept") + if acceptHeader == "" { + return defaultCodec + } + + for _, contentType := range strings.Split(acceptHeader, ",") { + codec, ok := api.codecs[strings.TrimSpace(contentType)] + if ok && codec.CanEncode(resp) { + return codec + } + } + + level.Warn(api.logger).Log("msg", "could not find suitable codec for response, falling back to default codec", "accept_header", acceptHeader) + return defaultCodec +} + func (api *API) respondError(w http.ResponseWriter, apiErr *apiError, data interface{}) { json := jsoniter.ConfigCompatibleWithStandardLibrary - b, err := json.Marshal(&response{ + b, err := json.Marshal(&Response{ Status: statusError, ErrorType: apiErr.typ, Error: apiErr.err.Error(), diff --git a/web/api/v1/api_test.go b/web/api/v1/api_test.go index 7e2dcbd8bb..617a8bdf3c 100644 --- a/web/api/v1/api_test.go +++ b/web/api/v1/api_test.go @@ -18,7 +18,6 @@ import ( "encoding/json" "fmt" "io" - "math" "net/http" "net/http/httptest" "net/url" @@ -30,7 +29,6 @@ import ( "testing" "time" - "github.com/prometheus/prometheus/model/histogram" "github.com/prometheus/prometheus/prompb" "github.com/prometheus/prometheus/util/stats" @@ -2765,39 +2763,93 @@ func TestAdminEndpoints(t *testing.T) { } func TestRespondSuccess(t *testing.T) { + api := API{ + logger: log.NewNopLogger(), + } + + api.InstallCodec(&testCodec{contentType: "test/cannot-encode", canEncode: false}) + api.InstallCodec(&testCodec{contentType: "test/can-encode", canEncode: true}) + api.InstallCodec(&testCodec{contentType: "test/can-encode-2", canEncode: true}) + s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { - api := API{} - api.respond(w, "test", nil) + api.respond(w, r, "test", nil) })) defer s.Close() - resp, err := http.Get(s.URL) - if err != nil { - t.Fatalf("Error on test request: %s", err) - } - body, err := io.ReadAll(resp.Body) - defer resp.Body.Close() - if err != nil { - t.Fatalf("Error reading response body: %s", err) - } + for _, tc := range []struct { + name string + acceptHeader string + expectedContentType string + expectedBody string + }{ + { + name: "no Accept header", + expectedContentType: "application/json", + expectedBody: `{"status":"success","data":"test"}`, + }, + { + name: "Accept header with single content type which is suitable", + acceptHeader: "test/can-encode", + expectedContentType: "test/can-encode", + expectedBody: `response from test/can-encode codec`, + }, + { + name: "Accept header with single content type which is not available", + acceptHeader: "test/not-registered", + expectedContentType: "application/json", + expectedBody: `{"status":"success","data":"test"}`, + }, + { + name: "Accept header with single content type which cannot encode the response payload", + acceptHeader: "test/cannot-encode", + expectedContentType: "application/json", + expectedBody: `{"status":"success","data":"test"}`, + }, + { + name: "Accept header with multiple content types, all of which are suitable", + acceptHeader: "test/can-encode, test/can-encode-2", + expectedContentType: "test/can-encode", + expectedBody: `response from test/can-encode codec`, + }, + { + name: "Accept header with multiple content types, only one of which is available", + acceptHeader: "test/not-registered, test/can-encode", + expectedContentType: "test/can-encode", + expectedBody: `response from test/can-encode codec`, + }, + { + name: "Accept header with multiple content types, only one of which can encode the response payload", + acceptHeader: "test/cannot-encode, test/can-encode", + expectedContentType: "test/can-encode", + expectedBody: `response from test/can-encode codec`, + }, + { + name: "Accept header with multiple content types, none of which are available", + acceptHeader: "test/not-registered, test/also-not-registered", + expectedContentType: "application/json", + expectedBody: `{"status":"success","data":"test"}`, + }, + } { + t.Run(tc.name, func(t *testing.T) { + req, err := http.NewRequest(http.MethodGet, s.URL, nil) + require.NoError(t, err) - if resp.StatusCode != 200 { - t.Fatalf("Return code %d expected in success response but got %d", 200, resp.StatusCode) - } - if h := resp.Header.Get("Content-Type"); h != "application/json" { - t.Fatalf("Expected Content-Type %q but got %q", "application/json", h) - } + if tc.acceptHeader != "" { + req.Header.Set("Accept", tc.acceptHeader) + } - var res response - if err = json.Unmarshal([]byte(body), &res); err != nil { - t.Fatalf("Error unmarshaling JSON body: %s", err) - } + resp, err := http.DefaultClient.Do(req) + require.NoError(t, err) - exp := &response{ - Status: statusSuccess, - Data: "test", + body, err := io.ReadAll(resp.Body) + defer resp.Body.Close() + require.NoError(t, err) + + require.Equal(t, http.StatusOK, resp.StatusCode) + require.Equal(t, tc.expectedContentType, resp.Header.Get("Content-Type")) + require.Equal(t, tc.expectedBody, string(body)) + }) } - require.Equal(t, exp, &res) } func TestRespondError(t *testing.T) { @@ -2824,12 +2876,12 @@ func TestRespondError(t *testing.T) { t.Fatalf("Expected Content-Type %q but got %q", "application/json", h) } - var res response + var res Response if err = json.Unmarshal([]byte(body), &res); err != nil { t.Fatalf("Error unmarshaling JSON body: %s", err) } - exp := &response{ + exp := &Response{ Status: statusError, Data: "test", ErrorType: errorTimeout, @@ -3047,165 +3099,6 @@ func TestOptionsMethod(t *testing.T) { } } -func TestRespond(t *testing.T) { - cases := []struct { - response interface{} - expected string - }{ - { - response: &queryData{ - ResultType: parser.ValueTypeMatrix, - Result: promql.Matrix{ - promql.Series{ - Points: []promql.Point{{V: 1, T: 1000}}, - Metric: labels.FromStrings("__name__", "foo"), - }, - }, - }, - expected: `{"status":"success","data":{"resultType":"matrix","result":[{"metric":{"__name__":"foo"},"values":[[1,"1"]]}]}}`, - }, - { - response: &queryData{ - ResultType: parser.ValueTypeMatrix, - Result: promql.Matrix{ - promql.Series{ - Points: []promql.Point{{H: &histogram.FloatHistogram{ - Schema: 2, - ZeroThreshold: 0.001, - ZeroCount: 12, - Count: 10, - Sum: 20, - PositiveSpans: []histogram.Span{ - {Offset: 3, Length: 2}, - {Offset: 1, Length: 3}, - }, - NegativeSpans: []histogram.Span{ - {Offset: 2, Length: 2}, - }, - PositiveBuckets: []float64{1, 2, 2, 1, 1}, - NegativeBuckets: []float64{2, 1}, - }, T: 1000}}, - Metric: labels.FromStrings("__name__", "foo"), - }, - }, - }, - expected: `{"status":"success","data":{"resultType":"matrix","result":[{"metric":{"__name__":"foo"},"histograms":[[1,{"count":"10","sum":"20","buckets":[[1,"-1.6817928305074288","-1.414213562373095","1"],[1,"-1.414213562373095","-1.189207115002721","2"],[3,"-0.001","0.001","12"],[0,"1.414213562373095","1.6817928305074288","1"],[0,"1.6817928305074288","2","2"],[0,"2.378414230005442","2.82842712474619","2"],[0,"2.82842712474619","3.3635856610148576","1"],[0,"3.3635856610148576","4","1"]]}]]}]}}`, - }, - { - response: promql.Point{V: 0, T: 0}, - expected: `{"status":"success","data":[0,"0"]}`, - }, - { - response: promql.Point{V: 20, T: 1}, - expected: `{"status":"success","data":[0.001,"20"]}`, - }, - { - response: promql.Point{V: 20, T: 10}, - expected: `{"status":"success","data":[0.010,"20"]}`, - }, - { - response: promql.Point{V: 20, T: 100}, - expected: `{"status":"success","data":[0.100,"20"]}`, - }, - { - response: promql.Point{V: 20, T: 1001}, - expected: `{"status":"success","data":[1.001,"20"]}`, - }, - { - response: promql.Point{V: 20, T: 1010}, - expected: `{"status":"success","data":[1.010,"20"]}`, - }, - { - response: promql.Point{V: 20, T: 1100}, - expected: `{"status":"success","data":[1.100,"20"]}`, - }, - { - response: promql.Point{V: 20, T: 12345678123456555}, - expected: `{"status":"success","data":[12345678123456.555,"20"]}`, - }, - { - response: promql.Point{V: 20, T: -1}, - expected: `{"status":"success","data":[-0.001,"20"]}`, - }, - { - response: promql.Point{V: math.NaN(), T: 0}, - expected: `{"status":"success","data":[0,"NaN"]}`, - }, - { - response: promql.Point{V: math.Inf(1), T: 0}, - expected: `{"status":"success","data":[0,"+Inf"]}`, - }, - { - response: promql.Point{V: math.Inf(-1), T: 0}, - expected: `{"status":"success","data":[0,"-Inf"]}`, - }, - { - response: promql.Point{V: 1.2345678e6, T: 0}, - expected: `{"status":"success","data":[0,"1234567.8"]}`, - }, - { - response: promql.Point{V: 1.2345678e-6, T: 0}, - expected: `{"status":"success","data":[0,"0.0000012345678"]}`, - }, - { - response: promql.Point{V: 1.2345678e-67, T: 0}, - expected: `{"status":"success","data":[0,"1.2345678e-67"]}`, - }, - { - response: []exemplar.QueryResult{ - { - SeriesLabels: labels.FromStrings("foo", "bar"), - Exemplars: []exemplar.Exemplar{ - { - Labels: labels.FromStrings("traceID", "abc"), - Value: 100.123, - Ts: 1234, - }, - }, - }, - }, - expected: `{"status":"success","data":[{"seriesLabels":{"foo":"bar"},"exemplars":[{"labels":{"traceID":"abc"},"value":"100.123","timestamp":1.234}]}]}`, - }, - { - response: []exemplar.QueryResult{ - { - SeriesLabels: labels.FromStrings("foo", "bar"), - Exemplars: []exemplar.Exemplar{ - { - Labels: labels.FromStrings("traceID", "abc"), - Value: math.Inf(1), - Ts: 1234, - }, - }, - }, - }, - expected: `{"status":"success","data":[{"seriesLabels":{"foo":"bar"},"exemplars":[{"labels":{"traceID":"abc"},"value":"+Inf","timestamp":1.234}]}]}`, - }, - } - - for _, c := range cases { - s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { - api := API{} - api.respond(w, c.response, nil) - })) - defer s.Close() - - resp, err := http.Get(s.URL) - if err != nil { - t.Fatalf("Error on test request: %s", err) - } - body, err := io.ReadAll(resp.Body) - defer resp.Body.Close() - if err != nil { - t.Fatalf("Error reading response body: %s", err) - } - - if string(body) != c.expected { - t.Fatalf("Expected response \n%v\n but got \n%v\n", c.expected, string(body)) - } - } -} - func TestTSDBStatus(t *testing.T) { tsdb := &fakeDB{} tsdbStatusAPI := func(api *API) apiFunc { return api.serveTSDBStatus } @@ -3281,6 +3174,8 @@ var testResponseWriter = httptest.ResponseRecorder{} func BenchmarkRespond(b *testing.B) { b.ReportAllocs() + request, err := http.NewRequest(http.MethodGet, "/does-not-matter", nil) + require.NoError(b, err) points := []promql.Point{} for i := 0; i < 10000; i++ { points = append(points, promql.Point{V: float64(i * 1000000), T: int64(i)}) @@ -3297,7 +3192,7 @@ func BenchmarkRespond(b *testing.B) { b.ResetTimer() api := API{} for n := 0; n < b.N; n++ { - api.respond(&testResponseWriter, response, nil) + api.respond(&testResponseWriter, request, response, nil) } } @@ -3408,3 +3303,20 @@ func TestGetGlobalURL(t *testing.T) { }) } } + +type testCodec struct { + contentType string + canEncode bool +} + +func (t *testCodec) ContentType() string { + return t.contentType +} + +func (t *testCodec) CanEncode(_ *Response) bool { + return t.canEncode +} + +func (t *testCodec) Encode(_ *Response) ([]byte, error) { + return []byte(fmt.Sprintf("response from %v codec", t.contentType)), nil +} diff --git a/web/api/v1/codec.go b/web/api/v1/codec.go new file mode 100644 index 0000000000..d11bb1fa01 --- /dev/null +++ b/web/api/v1/codec.go @@ -0,0 +1,26 @@ +// Copyright 2016 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 + +// A Codec performs encoding of API responses. +type Codec interface { + // ContentType returns the MIME time that this Codec emits. + ContentType() string + + // CanEncode determines if this Codec can encode resp. + CanEncode(resp *Response) bool + + // Encode encodes resp, ready for transmission to an API consumer. + Encode(resp *Response) ([]byte, error) +} diff --git a/web/api/v1/json_codec.go b/web/api/v1/json_codec.go new file mode 100644 index 0000000000..b38dab0385 --- /dev/null +++ b/web/api/v1/json_codec.go @@ -0,0 +1,32 @@ +// Copyright 2016 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 jsoniter "github.com/json-iterator/go" + +// JSONCodec is a Codec that encodes API responses as JSON. +type JSONCodec struct{} + +func (j JSONCodec) ContentType() string { + return "application/json" +} + +func (j JSONCodec) CanEncode(_ *Response) bool { + return true +} + +func (j JSONCodec) Encode(resp *Response) ([]byte, error) { + json := jsoniter.ConfigCompatibleWithStandardLibrary + return json.Marshal(resp) +} diff --git a/web/api/v1/json_codec_test.go b/web/api/v1/json_codec_test.go new file mode 100644 index 0000000000..c5b030ff9a --- /dev/null +++ b/web/api/v1/json_codec_test.go @@ -0,0 +1,178 @@ +// Copyright 2016 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 ( + "math" + "testing" + + "github.com/prometheus/prometheus/model/exemplar" + "github.com/prometheus/prometheus/model/histogram" + "github.com/prometheus/prometheus/model/labels" + "github.com/prometheus/prometheus/promql" + "github.com/prometheus/prometheus/promql/parser" +) + +func TestJsonCodec_Encode(t *testing.T) { + cases := []struct { + response interface{} + expected string + }{ + { + response: &queryData{ + ResultType: parser.ValueTypeMatrix, + Result: promql.Matrix{ + promql.Series{ + Points: []promql.Point{{V: 1, T: 1000}}, + Metric: labels.FromStrings("__name__", "foo"), + }, + }, + }, + expected: `{"status":"success","data":{"resultType":"matrix","result":[{"metric":{"__name__":"foo"},"values":[[1,"1"]]}]}}`, + }, + { + response: &queryData{ + ResultType: parser.ValueTypeMatrix, + Result: promql.Matrix{ + promql.Series{ + Points: []promql.Point{{H: &histogram.FloatHistogram{ + Schema: 2, + ZeroThreshold: 0.001, + ZeroCount: 12, + Count: 10, + Sum: 20, + PositiveSpans: []histogram.Span{ + {Offset: 3, Length: 2}, + {Offset: 1, Length: 3}, + }, + NegativeSpans: []histogram.Span{ + {Offset: 2, Length: 2}, + }, + PositiveBuckets: []float64{1, 2, 2, 1, 1}, + NegativeBuckets: []float64{2, 1}, + }, T: 1000}}, + Metric: labels.FromStrings("__name__", "foo"), + }, + }, + }, + expected: `{"status":"success","data":{"resultType":"matrix","result":[{"metric":{"__name__":"foo"},"histograms":[[1,{"count":"10","sum":"20","buckets":[[1,"-1.6817928305074288","-1.414213562373095","1"],[1,"-1.414213562373095","-1.189207115002721","2"],[3,"-0.001","0.001","12"],[0,"1.414213562373095","1.6817928305074288","1"],[0,"1.6817928305074288","2","2"],[0,"2.378414230005442","2.82842712474619","2"],[0,"2.82842712474619","3.3635856610148576","1"],[0,"3.3635856610148576","4","1"]]}]]}]}}`, + }, + { + response: promql.Point{V: 0, T: 0}, + expected: `{"status":"success","data":[0,"0"]}`, + }, + { + response: promql.Point{V: 20, T: 1}, + expected: `{"status":"success","data":[0.001,"20"]}`, + }, + { + response: promql.Point{V: 20, T: 10}, + expected: `{"status":"success","data":[0.010,"20"]}`, + }, + { + response: promql.Point{V: 20, T: 100}, + expected: `{"status":"success","data":[0.100,"20"]}`, + }, + { + response: promql.Point{V: 20, T: 1001}, + expected: `{"status":"success","data":[1.001,"20"]}`, + }, + { + response: promql.Point{V: 20, T: 1010}, + expected: `{"status":"success","data":[1.010,"20"]}`, + }, + { + response: promql.Point{V: 20, T: 1100}, + expected: `{"status":"success","data":[1.100,"20"]}`, + }, + { + response: promql.Point{V: 20, T: 12345678123456555}, + expected: `{"status":"success","data":[12345678123456.555,"20"]}`, + }, + { + response: promql.Point{V: 20, T: -1}, + expected: `{"status":"success","data":[-0.001,"20"]}`, + }, + { + response: promql.Point{V: math.NaN(), T: 0}, + expected: `{"status":"success","data":[0,"NaN"]}`, + }, + { + response: promql.Point{V: math.Inf(1), T: 0}, + expected: `{"status":"success","data":[0,"+Inf"]}`, + }, + { + response: promql.Point{V: math.Inf(-1), T: 0}, + expected: `{"status":"success","data":[0,"-Inf"]}`, + }, + { + response: promql.Point{V: 1.2345678e6, T: 0}, + expected: `{"status":"success","data":[0,"1234567.8"]}`, + }, + { + response: promql.Point{V: 1.2345678e-6, T: 0}, + expected: `{"status":"success","data":[0,"0.0000012345678"]}`, + }, + { + response: promql.Point{V: 1.2345678e-67, T: 0}, + expected: `{"status":"success","data":[0,"1.2345678e-67"]}`, + }, + { + response: []exemplar.QueryResult{ + { + SeriesLabels: labels.FromStrings("foo", "bar"), + Exemplars: []exemplar.Exemplar{ + { + Labels: labels.FromStrings("traceID", "abc"), + Value: 100.123, + Ts: 1234, + }, + }, + }, + }, + expected: `{"status":"success","data":[{"seriesLabels":{"foo":"bar"},"exemplars":[{"labels":{"traceID":"abc"},"value":"100.123","timestamp":1.234}]}]}`, + }, + { + response: []exemplar.QueryResult{ + { + SeriesLabels: labels.FromStrings("foo", "bar"), + Exemplars: []exemplar.Exemplar{ + { + Labels: labels.FromStrings("traceID", "abc"), + Value: math.Inf(1), + Ts: 1234, + }, + }, + }, + }, + expected: `{"status":"success","data":[{"seriesLabels":{"foo":"bar"},"exemplars":[{"labels":{"traceID":"abc"},"value":"+Inf","timestamp":1.234}]}]}`, + }, + } + + codec := JSONCodec{} + + for _, c := range cases { + body, err := codec.Encode(&Response{ + Status: statusSuccess, + Data: c.response, + }) + if err != nil { + t.Fatalf("Error encoding response body: %s", err) + } + + if string(body) != c.expected { + t.Fatalf("Expected response \n%v\n but got \n%v\n", c.expected, string(body)) + } + } +}