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// 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 remote
import (
"bufio"
"bytes"
"context"
"fmt"
"io"
"io/ioutil"
"net/http"
"time"
"github.com/gogo/protobuf/proto"
"github.com/golang/snappy"
"github.com/prometheus/common/model"
"github.com/prometheus/common/version"
config_util "github.com/prometheus/common/config"
"github.com/prometheus/prometheus/prompb"
)
const maxErrMsgLen = 256
var userAgent = fmt.Sprintf("Prometheus/%s", version.Version)
// Client allows reading and writing from/to a remote HTTP endpoint.
type Client struct {
index int // Used to differentiate clients in metrics.
url *config_util.URL
client *http.Client
timeout time.Duration
}
// ClientConfig configures a Client.
type ClientConfig struct {
URL *config_util.URL
Timeout model.Duration
HTTPClientConfig config_util.HTTPClientConfig
}
// NewClient creates a new Client.
func NewClient(index int, conf *ClientConfig) (*Client, error) {
httpClient, err := config_util.NewClientFromConfig(conf.HTTPClientConfig, "remote_storage")
if err != nil {
return nil, err
}
return &Client{
index: index,
url: conf.URL,
client: httpClient,
timeout: time.Duration(conf.Timeout),
}, nil
}
type recoverableError struct {
error
}
// Store sends a batch of samples to the HTTP endpoint.
func (c *Client) Store(ctx context.Context, req *prompb.WriteRequest) error {
data, err := proto.Marshal(req)
if err != nil {
return err
}
compressed := snappy.Encode(nil, data)
httpReq, err := http.NewRequest("POST", c.url.String(), bytes.NewReader(compressed))
if err != nil {
// Errors from NewRequest are from unparseable URLs, so are not
// recoverable.
return err
}
httpReq.Header.Add("Content-Encoding", "snappy")
httpReq.Header.Set("Content-Type", "application/x-protobuf")
httpReq.Header.Set("User-Agent", userAgent)
httpReq.Header.Set("X-Prometheus-Remote-Write-Version", "0.1.0")
httpReq = httpReq.WithContext(ctx)
ctx, cancel := context.WithTimeout(context.Background(), c.timeout)
defer cancel()
httpResp, err := c.client.Do(httpReq.WithContext(ctx))
if err != nil {
// Errors from client.Do are from (for example) network errors, so are
// recoverable.
return recoverableError{err}
}
defer httpResp.Body.Close()
if httpResp.StatusCode/100 != 2 {
scanner := bufio.NewScanner(io.LimitReader(httpResp.Body, maxErrMsgLen))
line := ""
if scanner.Scan() {
line = scanner.Text()
}
err = fmt.Errorf("server returned HTTP status %s: %s", httpResp.Status, line)
}
if httpResp.StatusCode/100 == 5 {
return recoverableError{err}
}
return err
}
// Name identifies the client.
func (c Client) Name() string {
return fmt.Sprintf("%d:%s", c.index, c.url)
}
// Read reads from a remote endpoint.
func (c *Client) Read(ctx context.Context, query *prompb.Query) (*prompb.QueryResult, error) {
req := &prompb.ReadRequest{
// TODO: Support batching multiple queries into one read request,
// as the protobuf interface allows for it.
Queries: []*prompb.Query{
query,
},
}
data, err := proto.Marshal(req)
if err != nil {
return nil, fmt.Errorf("unable to marshal read request: %v", err)
}
compressed := snappy.Encode(nil, data)
httpReq, err := http.NewRequest("POST", c.url.String(), bytes.NewReader(compressed))
if err != nil {
return nil, fmt.Errorf("unable to create request: %v", err)
}
httpReq.Header.Add("Content-Encoding", "snappy")
httpReq.Header.Add("Accept-Encoding", "snappy")
httpReq.Header.Set("Content-Type", "application/x-protobuf")
httpReq.Header.Set("User-Agent", userAgent)
httpReq.Header.Set("X-Prometheus-Remote-Read-Version", "0.1.0")
ctx, cancel := context.WithTimeout(ctx, c.timeout)
defer cancel()
httpResp, err := c.client.Do(httpReq.WithContext(ctx))
if err != nil {
return nil, fmt.Errorf("error sending request: %v", err)
}
defer httpResp.Body.Close()
if httpResp.StatusCode/100 != 2 {
return nil, fmt.Errorf("server returned HTTP status %s", httpResp.Status)
}
compressed, err = ioutil.ReadAll(httpResp.Body)
if err != nil {
return nil, fmt.Errorf("error reading response: %v", err)
}
uncompressed, err := snappy.Decode(nil, compressed)
if err != nil {
return nil, fmt.Errorf("error reading response: %v", err)
}
var resp prompb.ReadResponse
err = proto.Unmarshal(uncompressed, &resp)
if err != nil {
return nil, fmt.Errorf("unable to unmarshal response body: %v", err)
}
if len(resp.Results) != len(req.Queries) {
return nil, fmt.Errorf("responses: want %d, got %d", len(req.Queries), len(resp.Results))
}
return resp.Results[0], nil
}
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