telegraf/plugins/inputs/http_response/http_response.go

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package http_response
import (
"errors"
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"io"
"io/ioutil"
"log"
"net"
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"net/http"
"net/url"
"regexp"
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"strings"
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"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
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"github.com/influxdata/telegraf/plugins/inputs"
)
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// HTTPResponse struct
type HTTPResponse struct {
Address string
Body string
Method string
ResponseTimeout internal.Duration
Headers map[string]string
FollowRedirects bool
ResponseStringMatch 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
compiledStringMatch *regexp.Regexp
client *http.Client
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}
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// Description returns the plugin Description
func (h *HTTPResponse) Description() string {
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return "HTTP/HTTPS request given an address a method and a timeout"
}
var sampleConfig = `
## Server address (default http://localhost)
# address = "http://localhost"
## Set response_timeout (default 5 seconds)
# response_timeout = "5s"
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## HTTP Request Method
# method = "GET"
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## Whether to follow redirects from the server (defaults to false)
# follow_redirects = false
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## Optional HTTP Request Body
# body = '''
# {'fake':'data'}
# '''
## Optional substring or regex match in body of the response
# response_string_match = "\"service_status\": \"up\""
# response_string_match = "ok"
# response_string_match = "\".*_status\".?:.?\"up\""
## 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
## HTTP Request Headers (all values must be strings)
# [inputs.http_response.headers]
# Host = "github.com"
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`
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// SampleConfig returns the plugin SampleConfig
func (h *HTTPResponse) SampleConfig() string {
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return sampleConfig
}
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// ErrRedirectAttempted indicates that a redirect occurred
var ErrRedirectAttempted = errors.New("redirect")
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// CreateHttpClient creates an http client which will timeout at the specified
// timeout period and can follow redirects if specified
func (h *HTTPResponse) createHttpClient() (*http.Client, error) {
tlsCfg, err := internal.GetTLSConfig(
h.SSLCert, h.SSLKey, h.SSLCA, h.InsecureSkipVerify)
if err != nil {
return nil, err
}
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client := &http.Client{
Transport: &http.Transport{
Proxy: http.ProxyFromEnvironment,
DisableKeepAlives: true,
TLSClientConfig: tlsCfg,
},
Timeout: h.ResponseTimeout.Duration,
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}
if h.FollowRedirects == false {
client.CheckRedirect = func(req *http.Request, via []*http.Request) error {
return ErrRedirectAttempted
}
}
return client, nil
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}
// HTTPGather gathers all fields and returns any errors it encounters
func (h *HTTPResponse) httpGather() (map[string]interface{}, error) {
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// Prepare fields
fields := make(map[string]interface{})
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var body io.Reader
if h.Body != "" {
body = strings.NewReader(h.Body)
}
request, err := http.NewRequest(h.Method, h.Address, body)
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if err != nil {
return nil, err
}
for key, val := range h.Headers {
request.Header.Add(key, val)
if key == "Host" {
request.Host = val
}
}
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// Start Timer
start := time.Now()
resp, err := h.client.Do(request)
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if err != nil {
if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
fields["result_type"] = "timeout"
return fields, nil
}
fields["result_type"] = "connection_failed"
if h.FollowRedirects {
return fields, nil
}
if urlError, ok := err.(*url.Error); ok &&
urlError.Err == ErrRedirectAttempted {
err = nil
} else {
return fields, nil
}
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}
defer func() {
io.Copy(ioutil.Discard, resp.Body)
resp.Body.Close()
}()
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fields["response_time"] = time.Since(start).Seconds()
fields["http_response_code"] = resp.StatusCode
// Check the response for a regex match.
if h.ResponseStringMatch != "" {
// Compile once and reuse
if h.compiledStringMatch == nil {
h.compiledStringMatch = regexp.MustCompile(h.ResponseStringMatch)
if err != nil {
log.Printf("E! Failed to compile regular expression %s : %s", h.ResponseStringMatch, err)
fields["result_type"] = "response_string_mismatch"
return fields, nil
}
}
bodyBytes, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Printf("E! Failed to read body of HTTP Response : %s", err)
fields["result_type"] = "response_string_mismatch"
fields["response_string_match"] = 0
return fields, nil
}
if h.compiledStringMatch.Match(bodyBytes) {
fields["result_type"] = "success"
fields["response_string_match"] = 1
} else {
fields["result_type"] = "response_string_mismatch"
fields["response_string_match"] = 0
}
} else {
fields["result_type"] = "success"
}
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return fields, nil
}
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// Gather gets all metric fields and tags and returns any errors it encounters
func (h *HTTPResponse) Gather(acc telegraf.Accumulator) error {
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// Set default values
if h.ResponseTimeout.Duration < time.Second {
h.ResponseTimeout.Duration = time.Second * 5
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}
// Check send and expected string
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if h.Method == "" {
h.Method = "GET"
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}
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if h.Address == "" {
h.Address = "http://localhost"
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}
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addr, err := url.Parse(h.Address)
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if err != nil {
return err
}
if addr.Scheme != "http" && addr.Scheme != "https" {
return errors.New("Only http and https are supported")
}
// Prepare data
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tags := map[string]string{"server": h.Address, "method": h.Method}
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var fields map[string]interface{}
if h.client == nil {
client, err := h.createHttpClient()
if err != nil {
return err
}
h.client = client
}
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// Gather data
fields, err = h.httpGather()
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if err != nil {
return err
}
// Add metrics
acc.AddFields("http_response", fields, tags)
return nil
}
func init() {
inputs.Add("http_response", func() telegraf.Input {
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return &HTTPResponse{}
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})
}