From b5fa9b33cb644fb7600d791cde78baf32a252497 Mon Sep 17 00:00:00 2001
From: Luke Swithenbank <swithenbank.luke@gmail.com>
Date: Thu, 31 Mar 2016 20:53:51 +1100
Subject: [PATCH] add the ability to parse http headers

---
 plugins/inputs/http_response/http_response.go | 52 +++++++++++++------
 1 file changed, 36 insertions(+), 16 deletions(-)

diff --git a/plugins/inputs/http_response/http_response.go b/plugins/inputs/http_response/http_response.go
index d2d35025a..df21311ae 100644
--- a/plugins/inputs/http_response/http_response.go
+++ b/plugins/inputs/http_response/http_response.go
@@ -1,23 +1,28 @@
 package http_response
 
 import (
+	"bufio"
 	"errors"
 	"net/http"
+	"net/textproto"
 	"net/url"
+	"strings"
 	"time"
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/plugins/inputs"
 )
 
-// HttpResponses struct
-type HttpResponse struct {
+// HTTPResponse struct
+type HTTPResponse struct {
 	Address         string
 	Method          string
 	ResponseTimeout int
+	Headers         string
 }
 
-func (_ *HttpResponse) Description() string {
+// Description returns the plugin Description
+func (h *HTTPResponse) Description() string {
 	return "HTTP/HTTPS request given an address a method and a timeout"
 }
 
@@ -28,13 +33,19 @@ var sampleConfig = `
   response_timeout = 10
   ## HTTP Method
   method = "GET"
+  ## HTTP Request Headers
+  headers = '''
+  Host: github.com
+  '''
 `
 
-func (_ *HttpResponse) SampleConfig() string {
+// SampleConfig returns the plugin SampleConfig
+func (h *HTTPResponse) SampleConfig() string {
 	return sampleConfig
 }
 
-func (h *HttpResponse) HttpGather() (map[string]interface{}, error) {
+// HTTPGather gathers all fields and returns any errors it encounters
+func (h *HTTPResponse) HTTPGather() (map[string]interface{}, error) {
 	// Prepare fields
 	fields := make(map[string]interface{})
 
@@ -45,6 +56,14 @@ func (h *HttpResponse) HttpGather() (map[string]interface{}, error) {
 	if err != nil {
 		return nil, err
 	}
+	h.Headers = strings.TrimSpace(h.Headers) + "\n\n"
+	reader := bufio.NewReader(strings.NewReader(h.Headers))
+	tp := textproto.NewReader(reader)
+	mimeHeader, err := tp.ReadMIMEHeader()
+	if err != nil {
+		return nil, err
+	}
+	request.Header = http.Header(mimeHeader)
 	// Start Timer
 	start := time.Now()
 	resp, err := client.Do(request)
@@ -56,19 +75,20 @@ func (h *HttpResponse) HttpGather() (map[string]interface{}, error) {
 	return fields, nil
 }
 
-func (c *HttpResponse) Gather(acc telegraf.Accumulator) error {
+// Gather gets all metric fields and tags and returns any errors it encounters
+func (h *HTTPResponse) Gather(acc telegraf.Accumulator) error {
 	// Set default values
-	if c.ResponseTimeout < 1 {
-		c.ResponseTimeout = 1
+	if h.ResponseTimeout < 1 {
+		h.ResponseTimeout = 1
 	}
 	// Check send and expected string
-	if c.Method == "" {
-		c.Method = "GET"
+	if h.Method == "" {
+		h.Method = "GET"
 	}
-	if c.Address == "" {
-		c.Address = "http://localhost"
+	if h.Address == "" {
+		h.Address = "http://localhost"
 	}
-	addr, err := url.Parse(c.Address)
+	addr, err := url.Parse(h.Address)
 	if err != nil {
 		return err
 	}
@@ -76,10 +96,10 @@ func (c *HttpResponse) Gather(acc telegraf.Accumulator) error {
 		return errors.New("Only http and https are supported")
 	}
 	// Prepare data
-	tags := map[string]string{"server": c.Address, "method": c.Method}
+	tags := map[string]string{"server": h.Address, "method": h.Method}
 	var fields map[string]interface{}
 	// Gather data
-	fields, err = c.HttpGather()
+	fields, err = h.HTTPGather()
 	if err != nil {
 		return err
 	}
@@ -90,6 +110,6 @@ func (c *HttpResponse) Gather(acc telegraf.Accumulator) error {
 
 func init() {
 	inputs.Add("http_response", func() telegraf.Input {
-		return &HttpResponse{}
+		return &HTTPResponse{}
 	})
 }