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Merged
bboreham merged 9 commits into from
Feb 29, 2024
Merged

web/api add limit param #13396

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7a021bd
web/api add limit param
kartikaysaxena Jan 14, 2024
cda3049
lint fix
kartikaysaxena Jan 14, 2024
071af9d
suggestions implemented
kartikaysaxena Jan 18, 2024
8ea623d
added warnings when results are truncated
kartikaysaxena Feb 9, 2024
66ab452
lint
kartikaysaxena Feb 9, 2024
641d665
move logic upwards
kartikaysaxena Feb 9, 2024
a5f9b52
added warnings in label names and values API
kartikaysaxena Feb 9, 2024
140a6cb
suggestions implemented
kartikaysaxena Feb 15, 2024
2c88e61
suggestions implemented
kartikaysaxena Feb 28, 2024
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3 changes: 3 additions & 0 deletions docs/querying/api.md
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Original file line number Diff line number Diff line change
Expand Up @@ -256,6 +256,7 @@ URL query parameters:
series to return. At least one `match[]` argument must be provided.
- `start=<rfc3339 | unix_timestamp>`: Start timestamp.
- `end=<rfc3339 | unix_timestamp>`: End timestamp.
- `limit=<number>`: Maximum number of returned series. Optional.
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bboreham marked this conversation as resolved.

You can URL-encode these parameters directly in the request body by using the `POST` method and
`Content-Type: application/x-www-form-urlencoded` header. This is useful when specifying a large
Expand Down Expand Up @@ -306,6 +307,7 @@ URL query parameters:
- `end=<rfc3339 | unix_timestamp>`: End timestamp. Optional.
- `match[]=<series_selector>`: Repeated series selector argument that selects the
series from which to read the label names. Optional.
- `limit=<number>`: Maximum number of returned series. Optional.


The `data` section of the JSON response is a list of string label names.
Expand Down Expand Up @@ -356,6 +358,7 @@ URL query parameters:
- `end=<rfc3339 | unix_timestamp>`: End timestamp. Optional.
- `match[]=<series_selector>`: Repeated series selector argument that selects the
series from which to read the label values. Optional.
- `limit=<number>`: Maximum number of returned series. Optional.


The `data` section of the JSON response is a list of string label values.
Expand Down
52 changes: 50 additions & 2 deletions web/api/v1/api.go
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Original file line number Diff line number Diff line change
Expand Up @@ -644,6 +644,11 @@ func returnAPIError(err error) *apiError {
}

func (api *API) labelNames(r *http.Request) apiFuncResult {
limit, err := parseLimitParam(r.FormValue("limit"))
if err != nil {
return invalidParamError(err, "limit")
}

start, err := parseTimeParam(r, "start", MinTime)
if err != nil {
return invalidParamError(err, "start")
Expand Down Expand Up @@ -703,6 +708,11 @@ func (api *API) labelNames(r *http.Request) apiFuncResult {
if names == nil {
names = []string{}
}

if len(names) >= limit {
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@dimitarvdimitrov dimitarvdimitrov Mar 25, 2024

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shouldn't this check be len(names) == limit instead of >=? In this case the returned elements can be equal to the limit and also contain all elements in the database, but the response will still contain a warning. The same is used on the other two endpoints

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@machine424 machine424 May 17, 2024

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you mean len(names) > limit?
I opened #14116 to fix that.
Thanks and don't hesitate to open an issue for such "issues":)

names = names[:limit]
warnings = warnings.Add(errors.New("results truncated due to limit"))
}
return apiFuncResult{names, nil, warnings, nil}
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bboreham marked this conversation as resolved.
}

Expand All @@ -714,6 +724,11 @@ func (api *API) labelValues(r *http.Request) (result apiFuncResult) {
return apiFuncResult{nil, &apiError{errorBadData, fmt.Errorf("invalid label name: %q", name)}, nil, nil}
}

limit, err := parseLimitParam(r.FormValue("limit"))
if err != nil {
return invalidParamError(err, "limit")
}

start, err := parseTimeParam(r, "start", MinTime)
if err != nil {
return invalidParamError(err, "start")
Expand Down Expand Up @@ -783,6 +798,11 @@ func (api *API) labelValues(r *http.Request) (result apiFuncResult) {

slices.Sort(vals)

if len(vals) >= limit {
vals = vals[:limit]
warnings = warnings.Add(errors.New("results truncated due to limit"))
}

return apiFuncResult{vals, nil, warnings, closer}
}

Expand All @@ -809,6 +829,11 @@ func (api *API) series(r *http.Request) (result apiFuncResult) {
return apiFuncResult{nil, &apiError{errorBadData, errors.New("no match[] parameter provided")}, nil, nil}
}

limit, err := parseLimitParam(r.FormValue("limit"))
if err != nil {
return invalidParamError(err, "limit")
}

start, err := parseTimeParam(r, "start", MinTime)
if err != nil {
return invalidParamError(err, "start")
Expand Down Expand Up @@ -860,11 +885,17 @@ func (api *API) series(r *http.Request) (result apiFuncResult) {
}

metrics := []labels.Labels{}

warnings := set.Warnings()

for set.Next() {
metrics = append(metrics, set.At().Labels())
}

warnings := set.Warnings()
if len(metrics) >= limit {
warnings.Add(errors.New("results truncated due to limit"))
return apiFuncResult{metrics, nil, warnings, closer}
}
}
if set.Err() != nil {
return apiFuncResult{nil, returnAPIError(set.Err()), warnings, closer}
}
Expand Down Expand Up @@ -1868,3 +1899,20 @@ OUTER:
}
return matcherSets, nil
}

func parseLimitParam(limitStr string) (limit int, err error) {
limit = math.MaxInt
if limitStr == "" {
return limit, nil
}

limit, err = strconv.Atoi(limitStr)
if err != nil {
return limit, err
}
if limit <= 0 {
return limit, errors.New("limit must be positive")
}

return limit, nil
}
31 changes: 31 additions & 0 deletions web/api/v1/api_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1398,6 +1398,16 @@ func testEndpoints(t *testing.T, api *API, tr *testTargetRetriever, es storage.E
},
},
// Missing match[] query params in series requests.
{
endpoint: api.series,
query: url.Values{
"match[]": []string{"test_metric1"},
"limit": []string{"1"},
},
response: []labels.Labels{
labels.FromStrings("__name__", "test_metric1", "foo", "bar"),
},
},
{
endpoint: api.series,
errType: errorBadData,
Expand Down Expand Up @@ -2671,6 +2681,19 @@ func testEndpoints(t *testing.T, api *API, tr *testTargetRetriever, es storage.E
"boo",
},
},
{
endpoint: api.labelValues,
params: map[string]string{
"name": "foo",
},
query: url.Values{
"match[]": []string{"test_metric4"},
"limit": []string{"1"},
},
response: []string{
"bar",
},
},
// Label names.
{
endpoint: api.labelNames,
Expand Down Expand Up @@ -2810,6 +2833,14 @@ func testEndpoints(t *testing.T, api *API, tr *testTargetRetriever, es storage.E
},
response: []string{"__name__", "foo"},
},
{
endpoint: api.labelNames,
query: url.Values{
"match[]": []string{"test_metric2"},
"limit": []string{"1"},
},
response: []string{"__name__"},
},
}...)
}

Expand Down