telegraf/plugins/outputs/influxdb/client/http.go

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package client
import (
"bytes"
"crypto/tls"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"time"
)
var (
defaultRequestTimeout = time.Second * 5
)
//
func NewHTTP(config HTTPConfig, defaultWP WriteParams) (Client, error) {
// validate required parameters:
if len(config.URL) == 0 {
return nil, fmt.Errorf("config.URL is required to create an HTTP client")
}
if len(defaultWP.Database) == 0 {
return nil, fmt.Errorf("A default database is required to create an HTTP client")
}
// set defaults:
if config.Timeout == 0 {
config.Timeout = defaultRequestTimeout
}
// parse URL:
u, err := url.Parse(config.URL)
if err != nil {
return nil, fmt.Errorf("error parsing config.URL: %s", err)
}
if u.Scheme != "http" && u.Scheme != "https" {
return nil, fmt.Errorf("config.URL scheme must be http(s), got %s", u.Scheme)
}
return &httpClient{
writeURL: writeURL(u, defaultWP),
config: config,
url: u,
client: &http.Client{
Timeout: config.Timeout,
Transport: &http.Transport{
TLSClientConfig: config.TLSConfig,
},
},
}, nil
}
type HTTPConfig struct {
// URL should be of the form "http://host:port" (REQUIRED)
URL string
// UserAgent sets the User-Agent header.
UserAgent string
// Timeout specifies a time limit for requests made by this
// Client. The timeout includes connection time, any
// redirects, and reading the response body. The timer remains
// running after Get, Head, Post, or Do return and will
// interrupt reading of the Response.Body.
//
// A Timeout of zero means no timeout.
Timeout time.Duration
// Username is the basic auth username for the server.
Username string
// Password is the basic auth password for the server.
Password string
// TLSConfig is the tls auth settings to use for each request.
TLSConfig *tls.Config
// Gzip, if true, compresses each payload using gzip.
// TODO
// Gzip bool
}
// Response represents a list of statement results.
type Response struct {
// ignore Results:
Results []interface{} `json:"-"`
Err string `json:"error,omitempty"`
}
// Error returns the first error from any statement.
// Returns nil if no errors occurred on any statements.
func (r *Response) Error() error {
if r.Err != "" {
return fmt.Errorf(r.Err)
}
return nil
}
type httpClient struct {
writeURL string
config HTTPConfig
client *http.Client
url *url.URL
}
func (c *httpClient) Query(command string) error {
req, err := c.makeRequest(queryURL(c.url, command), bytes.NewReader([]byte("")))
if err != nil {
return err
}
return c.doRequest(req, http.StatusOK)
}
func (c *httpClient) Write(b []byte) (int, error) {
req, err := c.makeWriteRequest(bytes.NewReader(b), len(b), c.writeURL)
if err != nil {
return 0, nil
}
err = c.doRequest(req, http.StatusNoContent)
if err == nil {
return len(b), nil
}
return 0, err
}
func (c *httpClient) WriteWithParams(b []byte, wp WriteParams) (int, error) {
req, err := c.makeWriteRequest(bytes.NewReader(b), len(b), writeURL(c.url, wp))
if err != nil {
return 0, nil
}
err = c.doRequest(req, http.StatusNoContent)
if err == nil {
return len(b), nil
}
return 0, err
}
func (c *httpClient) WriteStream(r io.Reader, contentLength int) (int, error) {
req, err := c.makeWriteRequest(r, contentLength, c.writeURL)
if err != nil {
return 0, nil
}
err = c.doRequest(req, http.StatusNoContent)
if err == nil {
return contentLength, nil
}
return 0, err
}
func (c *httpClient) WriteStreamWithParams(
r io.Reader,
contentLength int,
wp WriteParams,
) (int, error) {
req, err := c.makeWriteRequest(r, contentLength, writeURL(c.url, wp))
if err != nil {
return 0, nil
}
err = c.doRequest(req, http.StatusNoContent)
if err == nil {
return contentLength, nil
}
return 0, err
}
func (c *httpClient) doRequest(
req *http.Request,
expectedCode int,
) error {
resp, err := c.client.Do(req)
if err != nil {
return err
}
code := resp.StatusCode
// If it's a "no content" response, then release and return nil
if code == http.StatusNoContent {
return nil
}
// not a "no content" response, so parse the result:
var response Response
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return fmt.Errorf("Fatal error reading body: %s", err)
}
decErr := json.Unmarshal(body, &response)
// If we got a JSON decode error, send that back
if decErr != nil {
err = fmt.Errorf("Unable to decode json: received status code %d err: %s", code, decErr)
}
// Unexpected response code OR error in JSON response body overrides
// a JSON decode error:
if code != expectedCode || response.Error() != nil {
err = fmt.Errorf("Response Error: Status Code [%d], expected [%d], [%v]",
code, expectedCode, response.Error())
}
return err
}
func (c *httpClient) makeWriteRequest(
body io.Reader,
contentLength int,
writeURL string,
) (*http.Request, error) {
req, err := c.makeRequest(writeURL, body)
if err != nil {
return nil, err
}
req.Header.Set("Content-Length", fmt.Sprint(contentLength))
// TODO
// if gzip {
// req.Header.Set("Content-Encoding", "gzip")
// }
return req, nil
}
func (c *httpClient) makeRequest(uri string, body io.Reader) (*http.Request, error) {
req, err := http.NewRequest("POST", uri, body)
if err != nil {
return nil, err
}
req.Header.Set("Content-Type", "text/plain")
req.Header.Set("User-Agent", c.config.UserAgent)
if c.config.Username != "" && c.config.Password != "" {
req.SetBasicAuth(c.config.Username, c.config.Password)
}
return req, nil
}
func (c *httpClient) Close() error {
// Nothing to do.
return nil
}
func writeURL(u *url.URL, wp WriteParams) string {
params := url.Values{}
params.Set("db", wp.Database)
if wp.RetentionPolicy != "" {
params.Set("rp", wp.RetentionPolicy)
}
if wp.Precision != "n" && wp.Precision != "" {
params.Set("precision", wp.Precision)
}
if wp.Consistency != "one" && wp.Consistency != "" {
params.Set("consistency", wp.Consistency)
}
u.RawQuery = params.Encode()
u.Path = "write"
return u.String()
}
func queryURL(u *url.URL, command string) string {
params := url.Values{}
params.Set("q", command)
u.RawQuery = params.Encode()
u.Path = "query"
return u.String()
}