telegraf/plugins/outputs/influxdb/http.go

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package influxdb
import (
"compress/gzip"
"context"
"crypto/tls"
"encoding/json"
"fmt"
"io"
"log"
"net/http"
"net/url"
"path"
"strings"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/serializers/influx"
)
type APIErrorType int
const (
_ APIErrorType = iota
DatabaseNotFound
)
const (
defaultRequestTimeout = time.Second * 5
defaultDatabase = "telegraf"
defaultUserAgent = "telegraf"
errStringDatabaseNotFound = "database not found"
errStringHintedHandoffNotEmpty = "hinted handoff queue not empty"
errStringPartialWrite = "partial write"
errStringPointsBeyondRP = "points beyond retention policy"
errStringUnableToParse = "unable to parse"
)
var (
// Escape an identifier in InfluxQL.
escapeIdentifier = strings.NewReplacer(
"\n", `\n`,
`\`, `\\`,
`"`, `\"`,
)
)
// APIError is an error reported by the InfluxDB server
type APIError struct {
StatusCode int
Title string
Description string
Type APIErrorType
}
func (e APIError) Error() string {
if e.Description != "" {
return fmt.Sprintf("%s: %s", e.Title, e.Description)
}
return e.Title
}
// QueryResponse is the response body from the /query endpoint
type QueryResponse struct {
Results []QueryResult `json:"results"`
}
type QueryResult struct {
Err string `json:"error,omitempty"`
}
func (r QueryResponse) Error() string {
if len(r.Results) > 0 {
return r.Results[0].Err
}
return ""
}
// WriteResponse is the response body from the /write endpoint
type WriteResponse struct {
Err string `json:"error,omitempty"`
}
func (r WriteResponse) Error() string {
return r.Err
}
type HTTPConfig struct {
URL *url.URL
UserAgent string
Timeout time.Duration
Username string
Password string
TLSConfig *tls.Config
Proxy *url.URL
Headers map[string]string
ContentEncoding string
Database string
RetentionPolicy string
Consistency string
Serializer *influx.Serializer
}
type httpClient struct {
WriteURL string
QueryURL string
ContentEncoding string
Timeout time.Duration
Username string
Password string
Headers map[string]string
client *http.Client
serializer *influx.Serializer
url *url.URL
database string
}
func NewHTTPClient(config *HTTPConfig) (*httpClient, error) {
if config.URL == nil {
return nil, ErrMissingURL
}
database := config.Database
if database == "" {
database = defaultDatabase
}
timeout := config.Timeout
if timeout == 0 {
timeout = defaultRequestTimeout
}
userAgent := config.UserAgent
if userAgent == "" {
userAgent = defaultUserAgent
}
var headers = make(map[string]string, len(config.Headers)+1)
headers["User-Agent"] = userAgent
for k, v := range config.Headers {
headers[k] = v
}
var proxy func(*http.Request) (*url.URL, error)
if config.Proxy != nil {
proxy = http.ProxyURL(config.Proxy)
} else {
proxy = http.ProxyFromEnvironment
}
serializer := config.Serializer
if serializer == nil {
serializer = influx.NewSerializer()
}
writeURL := makeWriteURL(
config.URL,
database,
config.RetentionPolicy,
config.Consistency)
queryURL := makeQueryURL(config.URL)
client := &httpClient{
serializer: serializer,
client: &http.Client{
Timeout: timeout,
Transport: &http.Transport{
Proxy: proxy,
TLSClientConfig: config.TLSConfig,
},
},
database: database,
url: config.URL,
WriteURL: writeURL,
QueryURL: queryURL,
ContentEncoding: config.ContentEncoding,
Timeout: timeout,
Username: config.Username,
Password: config.Password,
Headers: headers,
}
return client, nil
}
// URL returns the origin URL that this client connects too.
func (c *httpClient) URL() string {
return c.url.String()
}
// URL returns the database that this client connects too.
func (c *httpClient) Database() string {
return c.database
}
// CreateDatabase attemps to create a new database in the InfluxDB server.
// Note that some names are not allowed by the server, notably those with
// non-printable characters or slashes.
func (c *httpClient) CreateDatabase(ctx context.Context) error {
query := fmt.Sprintf(`CREATE DATABASE "%s"`,
escapeIdentifier.Replace(c.database))
req, err := c.makeQueryRequest(query)
resp, err := c.client.Do(req.WithContext(ctx))
if err != nil {
return err
}
defer resp.Body.Close()
queryResp := &QueryResponse{}
dec := json.NewDecoder(resp.Body)
err = dec.Decode(queryResp)
if err != nil {
if resp.StatusCode == 200 {
return nil
}
return &APIError{
StatusCode: resp.StatusCode,
Title: resp.Status,
}
}
// Even with a 200 response there can be an error
if resp.StatusCode == http.StatusOK && queryResp.Error() == "" {
return nil
}
return &APIError{
StatusCode: resp.StatusCode,
Title: resp.Status,
Description: queryResp.Error(),
}
}
// Write sends the metrics to InfluxDB
func (c *httpClient) Write(ctx context.Context, metrics []telegraf.Metric) error {
var err error
reader := influx.NewReader(metrics, c.serializer)
req, err := c.makeWriteRequest(reader)
if err != nil {
return err
}
resp, err := c.client.Do(req.WithContext(ctx))
if err != nil {
return err
}
defer resp.Body.Close()
if resp.StatusCode == http.StatusNoContent {
return nil
}
writeResp := &WriteResponse{}
dec := json.NewDecoder(resp.Body)
var desc string
err = dec.Decode(writeResp)
if err == nil {
desc = writeResp.Err
}
if strings.Contains(desc, errStringDatabaseNotFound) {
return &APIError{
StatusCode: resp.StatusCode,
Title: resp.Status,
Description: desc,
Type: DatabaseNotFound,
}
}
// This "error" is an informational message about the state of the
// InfluxDB cluster.
if strings.Contains(desc, errStringHintedHandoffNotEmpty) {
return nil
}
// Points beyond retention policy is returned when points are immediately
// discarded for being older than the retention policy. Usually this not
// a cause for concern and we don't want to retry.
if strings.Contains(desc, errStringPointsBeyondRP) {
log.Printf("W! [outputs.influxdb]: when writing to [%s]: received error %v",
c.URL(), desc)
return nil
}
// Other partial write errors, such as "field type conflict", are not
// correctable at this point and so the point is dropped instead of
// retrying.
if strings.Contains(desc, errStringPartialWrite) {
log.Printf("E! [outputs.influxdb]: when writing to [%s]: received error %v; discarding points",
c.URL(), desc)
return nil
}
// This error indicates a bug in either Telegraf line protocol
// serialization, retries would not be successful.
if strings.Contains(desc, errStringUnableToParse) {
log.Printf("E! [outputs.influxdb]: when writing to [%s]: received error %v; discarding points",
c.URL(), desc)
return nil
}
return &APIError{
StatusCode: resp.StatusCode,
Title: resp.Status,
Description: desc,
}
}
func (c *httpClient) makeQueryRequest(query string) (*http.Request, error) {
params := url.Values{}
params.Set("q", query)
form := strings.NewReader(params.Encode())
req, err := http.NewRequest("POST", c.QueryURL, form)
if err != nil {
return nil, err
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
c.addHeaders(req)
return req, nil
}
func (c *httpClient) makeWriteRequest(body io.Reader) (*http.Request, error) {
var err error
if c.ContentEncoding == "gzip" {
body, err = compressWithGzip(body)
if err != nil {
return nil, err
}
}
req, err := http.NewRequest("POST", c.WriteURL, body)
if err != nil {
return nil, err
}
req.Header.Set("Content-Type", "text/plain; charset=utf-8")
c.addHeaders(req)
if c.ContentEncoding == "gzip" {
req.Header.Set("Content-Encoding", "gzip")
}
return req, nil
}
func compressWithGzip(data io.Reader) (io.Reader, error) {
pr, pw := io.Pipe()
gw := gzip.NewWriter(pw)
var err error
go func() {
_, err = io.Copy(gw, data)
gw.Close()
pw.Close()
}()
return pr, err
}
func (c *httpClient) addHeaders(req *http.Request) {
if c.Username != "" || c.Password != "" {
req.SetBasicAuth(c.Username, c.Password)
}
for header, value := range c.Headers {
req.Header.Set(header, value)
}
}
func makeWriteURL(loc *url.URL, db, rp, consistency string) string {
params := url.Values{}
params.Set("db", db)
if rp != "" {
params.Set("rp", rp)
}
if consistency != "one" && consistency != "" {
params.Set("consistency", consistency)
}
u := *loc
u.Path = path.Join(u.Path, "write")
u.RawQuery = params.Encode()
return u.String()
}
func makeQueryURL(loc *url.URL) string {
u := *loc
u.Path = path.Join(u.Path, "query")
return u.String()
}