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Merge pull request #699 from joe-elliott/http-client-warnings
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Return Prometheus Warnings
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@beorn7
beorn7 committed Dec 13, 2019
2 parents 99d85f4 + 88792b1 commit e7776d2
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Showing 4 changed files with 232 additions and 166 deletions.
35 changes: 4 additions & 31 deletions api/client.go
View file
Expand Up @@ -25,8 +25,6 @@ import (
"time"
)

type Warnings []string

// DefaultRoundTripper is used if no RoundTripper is set in Config.
var DefaultRoundTripper http.RoundTripper = &http.Transport{
Proxy: http.ProxyFromEnvironment,
Expand Down Expand Up @@ -57,32 +55,7 @@ func (cfg *Config) roundTripper() http.RoundTripper {
// Client is the interface for an API client.
type Client interface {
URL(ep string, args map[string]string) *url.URL
Do(context.Context, *http.Request) (*http.Response, []byte, Warnings, error)
}

// DoGetFallback will attempt to do the request as-is, and on a 405 it will fallback to a GET request.
func DoGetFallback(c Client, ctx context.Context, u *url.URL, args url.Values) (*http.Response, []byte, Warnings, error) {
req, err := http.NewRequest(http.MethodPost, u.String(), strings.NewReader(args.Encode()))
if err != nil {
return nil, nil, nil, err
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

resp, body, warnings, err := c.Do(ctx, req)
if resp != nil && resp.StatusCode == http.StatusMethodNotAllowed {
u.RawQuery = args.Encode()
req, err = http.NewRequest(http.MethodGet, u.String(), nil)
if err != nil {
return nil, nil, warnings, err
}

} else {
if err != nil {
return resp, body, warnings, err
}
return resp, body, warnings, nil
}
return c.Do(ctx, req)
Do(context.Context, *http.Request) (*http.Response, []byte, error)
}

// NewClient returns a new Client.
Expand Down Expand Up @@ -120,7 +93,7 @@ func (c *httpClient) URL(ep string, args map[string]string) *url.URL {
return &u
}

func (c *httpClient) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, Warnings, error) {
func (c *httpClient) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
if ctx != nil {
req = req.WithContext(ctx)
}
Expand All @@ -132,7 +105,7 @@ func (c *httpClient) Do(ctx context.Context, req *http.Request) (*http.Response,
}()

if err != nil {
return nil, nil, nil, err
return nil, nil, err
}

var body []byte
Expand All @@ -152,5 +125,5 @@ func (c *httpClient) Do(ctx context.Context, req *http.Request) (*http.Response,
case <-done:
}

return resp, body, nil, err
return resp, body, err
}
72 changes: 0 additions & 72 deletions api/client_test.go
View file
Expand Up @@ -14,10 +14,7 @@
package api

import (
"context"
"encoding/json"
"net/http"
"net/http/httptest"
"net/url"
"testing"
)
Expand Down Expand Up @@ -114,72 +111,3 @@ func TestClientURL(t *testing.T) {
}
}
}

func TestDoGetFallback(t *testing.T) {
v := url.Values{"a": []string{"1", "2"}}

type testResponse struct {
Values string
Method string
}

// Start a local HTTP server.
server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
req.ParseForm()
r := &testResponse{
Values: req.Form.Encode(),
Method: req.Method,
}

body, _ := json.Marshal(r)

if req.Method == http.MethodPost {
if req.URL.Path == "/blockPost" {
http.Error(w, string(body), http.StatusMethodNotAllowed)
return
}
}

w.Write(body)
}))
// Close the server when test finishes.
defer server.Close()

u, err := url.Parse(server.URL)
if err != nil {
t.Fatal(err)
}
client := &httpClient{client: *(server.Client())}

// Do a post, and ensure that the post succeeds.
_, b, _, err := DoGetFallback(client, context.TODO(), u, v)
if err != nil {
t.Fatalf("Error doing local request: %v", err)
}
resp := &testResponse{}
if err := json.Unmarshal(b, resp); err != nil {
t.Fatal(err)
}
if resp.Method != http.MethodPost {
t.Fatalf("Mismatch method")
}
if resp.Values != v.Encode() {
t.Fatalf("Mismatch in values")
}

// Do a fallbcak to a get.
u.Path = "/blockPost"
_, b, _, err = DoGetFallback(client, context.TODO(), u, v)
if err != nil {
t.Fatalf("Error doing local request: %v", err)
}
if err := json.Unmarshal(b, resp); err != nil {
t.Fatal(err)
}
if resp.Method != http.MethodGet {
t.Fatalf("Mismatch method")
}
if resp.Values != v.Encode() {
t.Fatalf("Mismatch in values")
}
}
88 changes: 66 additions & 22 deletions api/prometheus/v1/api.go
View file
Expand Up @@ -21,7 +21,9 @@ import (
"fmt"
"math"
"net/http"
"net/url"
"strconv"
"strings"
"time"
"unsafe"

Expand Down Expand Up @@ -228,15 +230,15 @@ type API interface {
// Flags returns the flag values that Prometheus was launched with.
Flags(ctx context.Context) (FlagsResult, error)
// LabelNames returns all the unique label names present in the block in sorted order.
LabelNames(ctx context.Context) ([]string, api.Warnings, error)
LabelNames(ctx context.Context) ([]string, Warnings, error)
// LabelValues performs a query for the values of the given label.
LabelValues(ctx context.Context, label string) (model.LabelValues, api.Warnings, error)
LabelValues(ctx context.Context, label string) (model.LabelValues, Warnings, error)
// Query performs a query for the given time.
Query(ctx context.Context, query string, ts time.Time) (model.Value, api.Warnings, error)
Query(ctx context.Context, query string, ts time.Time) (model.Value, Warnings, error)
// QueryRange performs a query for the given range.
QueryRange(ctx context.Context, query string, r Range) (model.Value, api.Warnings, error)
QueryRange(ctx context.Context, query string, r Range) (model.Value, Warnings, error)
// Series finds series by label matchers.
Series(ctx context.Context, matches []string, startTime time.Time, endTime time.Time) ([]model.LabelSet, api.Warnings, error)
Series(ctx context.Context, matches []string, startTime time.Time, endTime time.Time) ([]model.LabelSet, Warnings, error)
// Snapshot creates a snapshot of all current data into snapshots/<datetime>-<rand>
// under the TSDB's data directory and returns the directory as response.
Snapshot(ctx context.Context, skipHead bool) (SnapshotResult, error)
Expand Down Expand Up @@ -515,11 +517,15 @@ func (qr *queryResult) UnmarshalJSON(b []byte) error {
//
// It is safe to use the returned API from multiple goroutines.
func NewAPI(c api.Client) API {
return &httpAPI{client: apiClient{c}}
return &httpAPI{
client: &apiClientImpl{
client: c,
},
}
}

type httpAPI struct {
client api.Client
client apiClient
}

func (h *httpAPI) Alerts(ctx context.Context) (AlertsResult, error) {
Expand Down Expand Up @@ -624,7 +630,7 @@ func (h *httpAPI) Flags(ctx context.Context) (FlagsResult, error) {
return res, json.Unmarshal(body, &res)
}

func (h *httpAPI) LabelNames(ctx context.Context) ([]string, api.Warnings, error) {
func (h *httpAPI) LabelNames(ctx context.Context) ([]string, Warnings, error) {
u := h.client.URL(epLabels, nil)
req, err := http.NewRequest(http.MethodGet, u.String(), nil)
if err != nil {
Expand All @@ -638,7 +644,7 @@ func (h *httpAPI) LabelNames(ctx context.Context) ([]string, api.Warnings, error
return labelNames, w, json.Unmarshal(body, &labelNames)
}

func (h *httpAPI) LabelValues(ctx context.Context, label string) (model.LabelValues, api.Warnings, error) {
func (h *httpAPI) LabelValues(ctx context.Context, label string) (model.LabelValues, Warnings, error) {
u := h.client.URL(epLabelValues, map[string]string{"name": label})
req, err := http.NewRequest(http.MethodGet, u.String(), nil)
if err != nil {
Expand All @@ -652,7 +658,7 @@ func (h *httpAPI) LabelValues(ctx context.Context, label string) (model.LabelVal
return labelValues, w, json.Unmarshal(body, &labelValues)
}

func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time) (model.Value, api.Warnings, error) {
func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time) (model.Value, Warnings, error) {
u := h.client.URL(epQuery, nil)
q := u.Query()

Expand All @@ -661,7 +667,7 @@ func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time) (model.
q.Set("time", formatTime(ts))
}

_, body, warnings, err := api.DoGetFallback(h.client, ctx, u, q)
_, body, warnings, err := h.client.DoGetFallback(ctx, u, q)
if err != nil {
return nil, warnings, err
}
Expand All @@ -670,7 +676,7 @@ func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time) (model.
return model.Value(qres.v), warnings, json.Unmarshal(body, &qres)
}

func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range) (model.Value, api.Warnings, error) {
func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range) (model.Value, Warnings, error) {
u := h.client.URL(epQueryRange, nil)
q := u.Query()

Expand All @@ -679,7 +685,7 @@ func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range) (model.
q.Set("end", formatTime(r.End))
q.Set("step", strconv.FormatFloat(r.Step.Seconds(), 'f', -1, 64))

_, body, warnings, err := api.DoGetFallback(h.client, ctx, u, q)
_, body, warnings, err := h.client.DoGetFallback(ctx, u, q)
if err != nil {
return nil, warnings, err
}
Expand All @@ -689,7 +695,7 @@ func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range) (model.
return model.Value(qres.v), warnings, json.Unmarshal(body, &qres)
}

func (h *httpAPI) Series(ctx context.Context, matches []string, startTime time.Time, endTime time.Time) ([]model.LabelSet, api.Warnings, error) {
func (h *httpAPI) Series(ctx context.Context, matches []string, startTime time.Time, endTime time.Time) ([]model.LabelSet, Warnings, error) {
u := h.client.URL(epSeries, nil)
q := u.Query()

Expand Down Expand Up @@ -796,10 +802,19 @@ func (h *httpAPI) TargetsMetadata(ctx context.Context, matchTarget string, metri
return res, json.Unmarshal(body, &res)
}

// Warnings is an array of non critical errors
type Warnings []string

// apiClient wraps a regular client and processes successful API responses.
// Successful also includes responses that errored at the API level.
type apiClient struct {
api.Client
type apiClient interface {
URL(ep string, args map[string]string) *url.URL
Do(context.Context, *http.Request) (*http.Response, []byte, Warnings, error)
DoGetFallback(ctx context.Context, u *url.URL, args url.Values) (*http.Response, []byte, Warnings, error)
}

type apiClientImpl struct {
client api.Client
}

type apiResponse struct {
Expand All @@ -825,17 +840,21 @@ func errorTypeAndMsgFor(resp *http.Response) (ErrorType, string) {
return ErrBadResponse, fmt.Sprintf("bad response code %d", resp.StatusCode)
}

func (c apiClient) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, api.Warnings, error) {
resp, body, warnings, err := c.Client.Do(ctx, req)
func (h *apiClientImpl) URL(ep string, args map[string]string) *url.URL {
return h.client.URL(ep, args)
}

func (h *apiClientImpl) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, Warnings, error) {
resp, body, err := h.client.Do(ctx, req)
if err != nil {
return resp, body, warnings, err
return resp, body, nil, err
}

code := resp.StatusCode

if code/100 != 2 && !apiError(code) {
errorType, errorMsg := errorTypeAndMsgFor(resp)
return resp, body, warnings, &Error{
return resp, body, nil, &Error{
Type: errorType,
Msg: errorMsg,
Detail: string(body),
Expand All @@ -846,7 +865,7 @@ func (c apiClient) Do(ctx context.Context, req *http.Request) (*http.Response, [

if http.StatusNoContent != code {
if jsonErr := json.Unmarshal(body, &result); jsonErr != nil {
return resp, body, warnings, &Error{
return resp, body, nil, &Error{
Type: ErrBadResponse,
Msg: jsonErr.Error(),
}
Expand All @@ -867,10 +886,35 @@ func (c apiClient) Do(ctx context.Context, req *http.Request) (*http.Response, [
}
}

return resp, []byte(result.Data), warnings, err
return resp, []byte(result.Data), result.Warnings, err

}

// DoGetFallback will attempt to do the request as-is, and on a 405 it will fallback to a GET request.
func (h *apiClientImpl) DoGetFallback(ctx context.Context, u *url.URL, args url.Values) (*http.Response, []byte, Warnings, error) {
req, err := http.NewRequest(http.MethodPost, u.String(), strings.NewReader(args.Encode()))
if err != nil {
return nil, nil, nil, err
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

resp, body, warnings, err := h.Do(ctx, req)
if resp != nil && resp.StatusCode == http.StatusMethodNotAllowed {
u.RawQuery = args.Encode()
req, err = http.NewRequest(http.MethodGet, u.String(), nil)
if err != nil {
return nil, nil, warnings, err
}

} else {
if err != nil {
return resp, body, warnings, err
}
return resp, body, warnings, nil
}
return h.Do(ctx, req)
}

func formatTime(t time.Time) string {
return strconv.FormatFloat(float64(t.Unix())+float64(t.Nanosecond())/1e9, 'f', -1, 64)
}

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