telegraf/plugins/inputs/http_response/http_response.go

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package http_response
import (
"errors"
"fmt"
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"io"
"io/ioutil"
"log"
"net"
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"net/http"
"net/url"
"regexp"
"strconv"
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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/internal/tls"
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"github.com/influxdata/telegraf/plugins/inputs"
)
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// HTTPResponse struct
type HTTPResponse struct {
Address string
HTTPProxy string `toml:"http_proxy"`
Body string
Method string
ResponseTimeout internal.Duration
Headers map[string]string
FollowRedirects bool
ResponseStringMatch string
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tls.ClientConfig
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 http_proxy (telegraf uses the system wide proxy settings if it's is not set)
# http_proxy = "http://localhost:8888"
## 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\""
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## Optional TLS Config
# tls_ca = "/etc/telegraf/ca.pem"
# tls_cert = "/etc/telegraf/cert.pem"
# tls_key = "/etc/telegraf/key.pem"
## Use TLS 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")
// Set the proxy. A configured proxy overwrites the system wide proxy.
func getProxyFunc(http_proxy string) func(*http.Request) (*url.URL, error) {
if http_proxy == "" {
return http.ProxyFromEnvironment
}
proxyURL, err := url.Parse(http_proxy)
if err != nil {
return func(_ *http.Request) (*url.URL, error) {
return nil, errors.New("bad proxy: " + err.Error())
}
}
return func(r *http.Request) (*url.URL, error) {
return proxyURL, nil
}
}
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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) {
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tlsCfg, err := h.ClientConfig.TLSConfig()
if err != nil {
return nil, err
}
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client := &http.Client{
Transport: &http.Transport{
Proxy: getProxyFunc(h.HTTPProxy),
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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}
func setResult(result_string string, fields map[string]interface{}, tags map[string]string) {
result_codes := map[string]int{
"success": 0,
"response_string_mismatch": 1,
"body_read_error": 2,
"connection_failed": 3,
"timeout": 4,
"dns_error": 5,
}
tags["result"] = result_string
fields["result_type"] = result_string
fields["result_code"] = result_codes[result_string]
}
func setError(err error, fields map[string]interface{}, tags map[string]string) error {
if timeoutError, ok := err.(net.Error); ok && timeoutError.Timeout() {
setResult("timeout", fields, tags)
return timeoutError
}
urlErr, isUrlErr := err.(*url.Error)
if !isUrlErr {
return nil
}
opErr, isNetErr := (urlErr.Err).(*net.OpError)
if isNetErr {
switch e := (opErr.Err).(type) {
case (*net.DNSError):
setResult("dns_error", fields, tags)
return e
case (*net.ParseError):
// Parse error has to do with parsing of IP addresses, so we
// group it with address errors
setResult("address_error", fields, tags)
return e
}
}
return nil
}
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// HTTPGather gathers all fields and returns any errors it encounters
func (h *HTTPResponse) httpGather() (map[string]interface{}, map[string]string, error) {
// Prepare fields and tags
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fields := make(map[string]interface{})
tags := map[string]string{"server": h.Address, "method": h.Method}
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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, nil, err
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}
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)
response_time := time.Since(start).Seconds()
// If an error in returned, it means we are dealing with a network error, as
// HTTP error codes do not generate errors in the net/http library
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if err != nil {
// Log error
log.Printf("D! Network error while polling %s: %s", h.Address, err.Error())
// Get error details
netErr := setError(err, fields, tags)
// If recognize the returnded error, get out
if netErr != nil {
return fields, tags, nil
}
// Any error not recognized by `set_error` is considered a "connection_failed"
setResult("connection_failed", fields, tags)
// If the error is a redirect we continue processing and log the HTTP code
urlError, isUrlError := err.(*url.Error)
if !h.FollowRedirects && isUrlError && urlError.Err == ErrRedirectAttempted {
err = nil
} else {
// If the error isn't a timeout or a redirect stop
// processing the request
return fields, tags, nil
}
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}
if _, ok := fields["response_time"]; !ok {
fields["response_time"] = response_time
}
// This function closes the response body, as
// required by the net/http library
defer func() {
io.Copy(ioutil.Discard, resp.Body)
resp.Body.Close()
}()
// Set log the HTTP response code
tags["status_code"] = strconv.Itoa(resp.StatusCode)
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fields["http_response_code"] = resp.StatusCode
// Check the response for a regex match.
if h.ResponseStringMatch != "" {
bodyBytes, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Printf("D! Failed to read body of HTTP Response : %s", err)
setResult("body_read_error", fields, tags)
fields["response_string_match"] = 0
return fields, tags, nil
}
if h.compiledStringMatch.Match(bodyBytes) {
setResult("success", fields, tags)
fields["response_string_match"] = 1
} else {
setResult("response_string_mismatch", fields, tags)
fields["response_string_match"] = 0
}
} else {
setResult("success", fields, tags)
}
return fields, tags, nil
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}
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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 {
// Compile the body regex if it exist
if h.compiledStringMatch == nil {
var err error
h.compiledStringMatch, err = regexp.Compile(h.ResponseStringMatch)
if err != nil {
return fmt.Errorf("Failed to compile regular expression %s : %s", h.ResponseStringMatch, err)
}
}
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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")
}
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// Prepare data
var fields map[string]interface{}
var tags map[string]string
if h.client == nil {
client, err := h.createHttpClient()
if err != nil {
return err
}
h.client = client
}
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// Gather data
fields, tags, err = h.httpGather()
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if err != nil {
return err
}
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// 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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})
}