telegraf/plugins/inputs/httpjson/httpjson.go

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package httpjson
import (
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"errors"
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"fmt"
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"io/ioutil"
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"net/http"
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"net/url"
"strings"
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"sync"
"time"
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"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
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"github.com/influxdata/telegraf/plugins/inputs"
"github.com/influxdata/telegraf/plugins/parsers"
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)
type HttpJson struct {
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Name string
Servers []string
Method string
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TagKeys []string
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Parameters map[string]string
Headers map[string]string
// Path to CA file
SSLCA string `toml:"ssl_ca"`
// Path to host cert file
SSLCert string `toml:"ssl_cert"`
// Path to cert key file
SSLKey string `toml:"ssl_key"`
// Use SSL but skip chain & host verification
InsecureSkipVerify bool
client HTTPClient
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}
type HTTPClient interface {
// Returns the result of an http request
//
// Parameters:
// req: HTTP request object
//
// Returns:
// http.Response: HTTP respons object
// error : Any error that may have occurred
MakeRequest(req *http.Request) (*http.Response, error)
SetHTTPClient(client *http.Client)
HTTPClient() *http.Client
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}
type RealHTTPClient struct {
client *http.Client
}
func (c *RealHTTPClient) MakeRequest(req *http.Request) (*http.Response, error) {
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return c.client.Do(req)
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}
func (c *RealHTTPClient) SetHTTPClient(client *http.Client) {
c.client = client
}
func (c *RealHTTPClient) HTTPClient() *http.Client {
return c.client
}
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var sampleConfig = `
## NOTE This plugin only reads numerical measurements, strings and booleans
## will be ignored.
## a name for the service being polled
name = "webserver_stats"
## URL of each server in the service's cluster
servers = [
"http://localhost:9999/stats/",
"http://localhost:9998/stats/",
]
## HTTP method to use: GET or POST (case-sensitive)
method = "GET"
## List of tag names to extract from top-level of JSON server response
# tag_keys = [
# "my_tag_1",
# "my_tag_2"
# ]
## HTTP parameters (all values must be strings)
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[inputs.httpjson.parameters]
event_type = "cpu_spike"
threshold = "0.75"
## HTTP Header parameters (all values must be strings)
# [inputs.httpjson.headers]
# X-Auth-Token = "my-xauth-token"
# apiVersion = "v1"
## Optional SSL Config
# ssl_ca = "/etc/telegraf/ca.pem"
# ssl_cert = "/etc/telegraf/cert.pem"
# ssl_key = "/etc/telegraf/key.pem"
## Use SSL but skip chain & host verification
# insecure_skip_verify = false
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`
func (h *HttpJson) SampleConfig() string {
return sampleConfig
}
func (h *HttpJson) Description() string {
return "Read flattened metrics from one or more JSON HTTP endpoints"
}
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// Gathers data for all servers.
func (h *HttpJson) Gather(acc telegraf.Accumulator) error {
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var wg sync.WaitGroup
if h.client.HTTPClient() == nil {
tlsCfg, err := internal.GetTLSConfig(
h.SSLCert, h.SSLKey, h.SSLCA, h.InsecureSkipVerify)
if err != nil {
return err
}
tr := &http.Transport{
ResponseHeaderTimeout: time.Duration(3 * time.Second),
TLSClientConfig: tlsCfg,
}
client := &http.Client{
Transport: tr,
Timeout: time.Duration(4 * time.Second),
}
h.client.SetHTTPClient(client)
}
errorChannel := make(chan error, len(h.Servers))
for _, server := range h.Servers {
wg.Add(1)
go func(server string) {
defer wg.Done()
if err := h.gatherServer(acc, server); err != nil {
errorChannel <- err
}
}(server)
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}
wg.Wait()
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close(errorChannel)
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// Get all errors and return them as one giant error
errorStrings := []string{}
for err := range errorChannel {
errorStrings = append(errorStrings, err.Error())
}
if len(errorStrings) == 0 {
return nil
}
return errors.New(strings.Join(errorStrings, "\n"))
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}
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// Gathers data from a particular server
// Parameters:
// acc : The telegraf Accumulator to use
// serverURL: endpoint to send request to
// service : the service being queried
//
// Returns:
// error: Any error that may have occurred
func (h *HttpJson) gatherServer(
acc telegraf.Accumulator,
serverURL string,
) error {
resp, responseTime, err := h.sendRequest(serverURL)
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if err != nil {
return err
}
var msrmnt_name string
if h.Name == "" {
msrmnt_name = "httpjson"
} else {
msrmnt_name = "httpjson_" + h.Name
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}
tags := map[string]string{
"server": serverURL,
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}
parser, err := parsers.NewJSONParser(msrmnt_name, h.TagKeys, tags)
if err != nil {
return err
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}
metrics, err := parser.Parse([]byte(resp))
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if err != nil {
return err
}
for _, metric := range metrics {
fields := make(map[string]interface{})
for k, v := range metric.Fields() {
fields[k] = v
}
fields["response_time"] = responseTime
acc.AddFields(metric.Name(), fields, metric.Tags())
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}
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return nil
}
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// Sends an HTTP request to the server using the HttpJson object's HTTPClient.
// This request can be either a GET or a POST.
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// Parameters:
// serverURL: endpoint to send request to
//
// Returns:
// string: body of the response
// error : Any error that may have occurred
func (h *HttpJson) sendRequest(serverURL string) (string, float64, error) {
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// Prepare URL
requestURL, err := url.Parse(serverURL)
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if err != nil {
return "", -1, fmt.Errorf("Invalid server URL \"%s\"", serverURL)
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}
data := url.Values{}
switch {
case h.Method == "GET":
params := requestURL.Query()
for k, v := range h.Parameters {
params.Add(k, v)
}
requestURL.RawQuery = params.Encode()
case h.Method == "POST":
requestURL.RawQuery = ""
for k, v := range h.Parameters {
data.Add(k, v)
}
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}
// Create + send request
req, err := http.NewRequest(h.Method, requestURL.String(),
strings.NewReader(data.Encode()))
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if err != nil {
return "", -1, err
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}
// Add header parameters
for k, v := range h.Headers {
if strings.ToLower(k) == "host" {
req.Host = v
} else {
req.Header.Add(k, v)
}
}
start := time.Now()
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resp, err := h.client.MakeRequest(req)
if err != nil {
return "", -1, err
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}
defer resp.Body.Close()
responseTime := time.Since(start).Seconds()
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body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return string(body), responseTime, err
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}
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// Process response
if resp.StatusCode != http.StatusOK {
err = fmt.Errorf("Response from url \"%s\" has status code %d (%s), expected %d (%s)",
requestURL.String(),
resp.StatusCode,
http.StatusText(resp.StatusCode),
http.StatusOK,
http.StatusText(http.StatusOK))
return string(body), responseTime, err
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}
return string(body), responseTime, err
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}
func init() {
inputs.Add("httpjson", func() telegraf.Input {
return &HttpJson{
client: &RealHTTPClient{},
}
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})
}