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Merge pull request #13997 from bboreham/api-marshalling
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bugfix: API: encode empty Vector/Matrix as [] not null
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@ArthurSens
ArthurSens committed Apr 29, 2024
2 parents 2950521 + 5c8ffaa commit 3d42466
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Showing 2 changed files with 77 additions and 38 deletions.
40 changes: 26 additions & 14 deletions web/api/v1/api_test.go
View file
Expand Up @@ -15,7 +15,6 @@ package v1

import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
Expand All @@ -35,6 +34,7 @@ import (
"github.com/prometheus/prometheus/util/testutil"

"github.com/go-kit/log"
jsoniter "github.com/json-iterator/go"
"github.com/prometheus/client_golang/prometheus"
config_util "github.com/prometheus/common/config"
"github.com/prometheus/common/model"
Expand Down Expand Up @@ -910,6 +910,7 @@ func TestStats(t *testing.T) {
require.IsType(t, &QueryData{}, i)
qd := i.(*QueryData)
require.NotNil(t, qd.Stats)
json := jsoniter.ConfigCompatibleWithStandardLibrary
j, err := json.Marshal(qd.Stats)
require.NoError(t, err)
require.JSONEq(t, `{"custom":"Custom Value"}`, string(j))
Expand Down Expand Up @@ -1171,6 +1172,25 @@ func testEndpoints(t *testing.T, api *API, tr *testTargetRetriever, es storage.E
},
},
},
// Test empty vector result
{
endpoint: api.query,
query: url.Values{
"query": []string{"bottomk(2, notExists)"},
},
responseAsJSON: `{"resultType":"vector","result":[]}`,
},
// Test empty matrix result
{
endpoint: api.queryRange,
query: url.Values{
"query": []string{"bottomk(2, notExists)"},
"start": []string{"0"},
"end": []string{"2"},
"step": []string{"1"},
},
responseAsJSON: `{"resultType":"matrix","result":[]}`,
},
// Missing query params in range queries.
{
endpoint: api.queryRange,
Expand Down Expand Up @@ -2891,10 +2911,13 @@ func testEndpoints(t *testing.T, api *API, tr *testTargetRetriever, es storage.E
if test.zeroFunc != nil {
test.zeroFunc(res.data)
}
assertAPIResponse(t, res.data, test.response)
if test.response != nil {
assertAPIResponse(t, res.data, test.response)
}
}

if test.responseAsJSON != "" {
json := jsoniter.ConfigCompatibleWithStandardLibrary
s, err := json.Marshal(res.data)
require.NoError(t, err)
require.JSONEq(t, test.responseAsJSON, string(s))
Expand Down Expand Up @@ -3292,18 +3315,7 @@ func TestRespondError(t *testing.T) {
require.Equal(t, want, have, "Return code %d expected in error response but got %d", want, have)
h := resp.Header.Get("Content-Type")
require.Equal(t, "application/json", h, "Expected Content-Type %q but got %q", "application/json", h)

var res Response
err = json.Unmarshal(body, &res)
require.NoError(t, err, "Error unmarshaling JSON body")

exp := &Response{
Status: statusError,
Data: "test",
ErrorType: errorTimeout,
Error: "message",
}
require.Equal(t, exp, &res)
require.JSONEq(t, `{"status": "error", "data": "test", "errorType": "timeout", "error": "message"}`, string(body))
}

func TestParseTimeParam(t *testing.T) {
Expand Down
75 changes: 51 additions & 24 deletions web/api/v1/json_codec.go
View file
Expand Up @@ -25,11 +25,13 @@ import (
)

func init() {
jsoniter.RegisterTypeEncoderFunc("promql.Series", marshalSeriesJSON, marshalSeriesJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.Sample", marshalSampleJSON, marshalSampleJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.FPoint", marshalFPointJSON, marshalPointJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.HPoint", marshalHPointJSON, marshalPointJSONIsEmpty)
jsoniter.RegisterTypeEncoderFunc("exemplar.Exemplar", marshalExemplarJSON, marshalExemplarJSONEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.Vector", unsafeMarshalVectorJSON, neverEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.Matrix", unsafeMarshalMatrixJSON, neverEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.Series", unsafeMarshalSeriesJSON, neverEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.Sample", unsafeMarshalSampleJSON, neverEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.FPoint", unsafeMarshalFPointJSON, neverEmpty)
jsoniter.RegisterTypeEncoderFunc("promql.HPoint", unsafeMarshalHPointJSON, neverEmpty)
jsoniter.RegisterTypeEncoderFunc("exemplar.Exemplar", marshalExemplarJSON, neverEmpty)
jsoniter.RegisterTypeEncoderFunc("labels.Labels", unsafeMarshalLabelsJSON, labelsIsEmpty)
}

Expand Down Expand Up @@ -66,8 +68,12 @@ func (j JSONCodec) Encode(resp *Response) ([]byte, error) {
// < more histograms >
// ],
// },
func marshalSeriesJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
func unsafeMarshalSeriesJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
s := *((*promql.Series)(ptr))
marshalSeriesJSON(s, stream)
}

func marshalSeriesJSON(s promql.Series, stream *jsoniter.Stream) {
stream.WriteObjectStart()
stream.WriteObjectField(`metric`)
marshalLabelsJSON(s.Metric, stream)
Expand All @@ -78,7 +84,7 @@ func marshalSeriesJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
stream.WriteObjectField(`values`)
stream.WriteArrayStart()
}
marshalFPointJSON(unsafe.Pointer(&p), stream)
marshalFPointJSON(p, stream)
}
if len(s.Floats) > 0 {
stream.WriteArrayEnd()
Expand All @@ -89,15 +95,16 @@ func marshalSeriesJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
stream.WriteObjectField(`histograms`)
stream.WriteArrayStart()
}
marshalHPointJSON(unsafe.Pointer(&p), stream)
marshalHPointJSON(p, stream)
}
if len(s.Histograms) > 0 {
stream.WriteArrayEnd()
}
stream.WriteObjectEnd()
}

func marshalSeriesJSONIsEmpty(unsafe.Pointer) bool {
// In the Prometheus API we render an empty object as `[]` or similar.
func neverEmpty(unsafe.Pointer) bool {
return false
}

Expand All @@ -122,8 +129,12 @@ func marshalSeriesJSONIsEmpty(unsafe.Pointer) bool {
// },
// "histogram": [ 1435781451.781, { < histogram, see jsonutil.MarshalHistogram > } ]
// },
func marshalSampleJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
func unsafeMarshalSampleJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
s := *((*promql.Sample)(ptr))
marshalSampleJSON(s, stream)
}

func marshalSampleJSON(s promql.Sample, stream *jsoniter.Stream) {
stream.WriteObjectStart()
stream.WriteObjectField(`metric`)
marshalLabelsJSON(s.Metric, stream)
Expand All @@ -145,13 +156,13 @@ func marshalSampleJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
stream.WriteObjectEnd()
}

func marshalSampleJSONIsEmpty(unsafe.Pointer) bool {
return false
}

// marshalFPointJSON writes `[ts, "1.234"]`.
func marshalFPointJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
func unsafeMarshalFPointJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
p := *((*promql.FPoint)(ptr))
marshalFPointJSON(p, stream)
}

func marshalFPointJSON(p promql.FPoint, stream *jsoniter.Stream) {
stream.WriteArrayStart()
jsonutil.MarshalTimestamp(p.T, stream)
stream.WriteMore()
Expand All @@ -160,19 +171,19 @@ func marshalFPointJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
}

// marshalHPointJSON writes `[ts, { < histogram, see jsonutil.MarshalHistogram > } ]`.
func marshalHPointJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
func unsafeMarshalHPointJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
p := *((*promql.HPoint)(ptr))
marshalHPointJSON(p, stream)
}

func marshalHPointJSON(p promql.HPoint, stream *jsoniter.Stream) {
stream.WriteArrayStart()
jsonutil.MarshalTimestamp(p.T, stream)
stream.WriteMore()
jsonutil.MarshalHistogram(p.H, stream)
stream.WriteArrayEnd()
}

func marshalPointJSONIsEmpty(unsafe.Pointer) bool {
return false
}

// marshalExemplarJSON writes.
//
// {
Expand Down Expand Up @@ -201,10 +212,6 @@ func marshalExemplarJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
stream.WriteObjectEnd()
}

func marshalExemplarJSONEmpty(unsafe.Pointer) bool {
return false
}

func unsafeMarshalLabelsJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
labelsPtr := (*labels.Labels)(ptr)
marshalLabelsJSON(*labelsPtr, stream)
Expand All @@ -229,3 +236,23 @@ func labelsIsEmpty(ptr unsafe.Pointer) bool {
labelsPtr := (*labels.Labels)(ptr)
return labelsPtr.IsEmpty()
}

// Marshal a Vector as `[sample,sample,...]` - empty Vector is `[]`.
func unsafeMarshalVectorJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
v := *((*promql.Vector)(ptr))
stream.WriteArrayStart()
for _, s := range v {
marshalSampleJSON(s, stream)
}
stream.WriteArrayEnd()
}

// Marshal a Matrix as `[series,series,...]` - empty Matrix is `[]`.
func unsafeMarshalMatrixJSON(ptr unsafe.Pointer, stream *jsoniter.Stream) {
m := *((*promql.Matrix)(ptr))
stream.WriteArrayStart()
for _, s := range m {
marshalSeriesJSON(s, stream)
}
stream.WriteArrayEnd()
}

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