From f947fa86e37a1679eacb7ae98b06a8826d03a5d3 Mon Sep 17 00:00:00 2001
From: Luke Swithenbank <swithenbank.luke@gmail.com>
Date: Thu, 31 Mar 2016 21:18:19 +1100
Subject: [PATCH] update to allow for following redirects

---
 plugins/inputs/http_response/README.md        | 19 +++++++----
 plugins/inputs/http_response/http_response.go | 33 ++++++++++++++++---
 2 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/plugins/inputs/http_response/README.md b/plugins/inputs/http_response/README.md
index b70bbde72..99770e526 100644
--- a/plugins/inputs/http_response/README.md
+++ b/plugins/inputs/http_response/README.md
@@ -7,12 +7,18 @@ This input plugin will test HTTP/HTTPS connections.
 ```
 # List of UDP/TCP connections you want to check
 [[inputs.http_response]]
-  # Server address (default http://localhost)
-  address = "https://github.com"
-  # Set http response timeout (default 10)
+  ## Server address (default http://localhost)
+  address = "http://github.com"
+  ## Set response_timeout (default 10 seconds)
   response_timeout = 10
-  # HTTP Method (default "GET")
+  ## HTTP Method
   method = "GET"
+  ## HTTP Request Headers
+  headers = '''
+  Host: github.com
+  '''
+  ## Whether to follow redirects from the server (defaults to false)
+  follow_redirects = true
 ```
 
 ### Measurements & Fields:
@@ -25,12 +31,11 @@ This input plugin will test HTTP/HTTPS connections.
 
 - All measurements have the following tags:
     - server
-    - port
-    - protocol
+    - method
 
 ### Example Output:
 
 ```
 $ ./telegraf -config telegraf.conf -input-filter http_response -test
-http_response,server=http://192.168.2.2:2000,method=GET response_time=0.18070360500000002,http_response_code=200 1454785464182527094
+http_response,method=GET,server=http://www.github.com http_response_code=200i,response_time=6.223266528 1459419354977857955
 ```
diff --git a/plugins/inputs/http_response/http_response.go b/plugins/inputs/http_response/http_response.go
index df21311ae..09569fe73 100644
--- a/plugins/inputs/http_response/http_response.go
+++ b/plugins/inputs/http_response/http_response.go
@@ -3,9 +3,11 @@ package http_response
 import (
 	"bufio"
 	"errors"
+	"fmt"
 	"net/http"
 	"net/textproto"
 	"net/url"
+	"os"
 	"strings"
 	"time"
 
@@ -19,6 +21,7 @@ type HTTPResponse struct {
 	Method          string
 	ResponseTimeout int
 	Headers         string
+	FollowRedirects bool
 }
 
 // Description returns the plugin Description
@@ -28,8 +31,8 @@ func (h *HTTPResponse) Description() string {
 
 var sampleConfig = `
   ## Server address (default http://localhost)
-  address = "https://github.com"
-  ## Set response_timeout (default 1 seconds)
+  address = "http://github.com"
+  ## Set response_timeout (default 10 seconds)
   response_timeout = 10
   ## HTTP Method
   method = "GET"
@@ -37,6 +40,8 @@ var sampleConfig = `
   headers = '''
   Host: github.com
   '''
+	## Whether to follow redirects from the server (defaults to false)
+	follow_redirects = true
 `
 
 // SampleConfig returns the plugin SampleConfig
@@ -44,6 +49,8 @@ func (h *HTTPResponse) SampleConfig() string {
 	return sampleConfig
 }
 
+var ErrRedirectAttempted = errors.New("redirect")
+
 // HTTPGather gathers all fields and returns any errors it encounters
 func (h *HTTPResponse) HTTPGather() (map[string]interface{}, error) {
 	// Prepare fields
@@ -52,6 +59,14 @@ func (h *HTTPResponse) HTTPGather() (map[string]interface{}, error) {
 	client := &http.Client{
 		Timeout: time.Second * time.Duration(h.ResponseTimeout),
 	}
+
+	if h.FollowRedirects == false {
+		fmt.Println(h.FollowRedirects)
+		client.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+			return ErrRedirectAttempted
+		}
+	}
+
 	request, err := http.NewRequest(h.Method, h.Address, nil)
 	if err != nil {
 		return nil, err
@@ -66,9 +81,19 @@ func (h *HTTPResponse) HTTPGather() (map[string]interface{}, error) {
 	request.Header = http.Header(mimeHeader)
 	// Start Timer
 	start := time.Now()
+	request.Write(os.Stdout)
 	resp, err := client.Do(request)
 	if err != nil {
-		return nil, err
+		if h.FollowRedirects {
+			return nil, err
+		}
+		if urlError, ok := err.(*url.Error); ok &&
+			urlError.Err == ErrRedirectAttempted {
+			fmt.Println(err)
+			err = nil
+		} else {
+			return nil, err
+		}
 	}
 	fields["response_time"] = time.Since(start).Seconds()
 	fields["http_response_code"] = resp.StatusCode
@@ -79,7 +104,7 @@ func (h *HTTPResponse) HTTPGather() (map[string]interface{}, error) {
 func (h *HTTPResponse) Gather(acc telegraf.Accumulator) error {
 	// Set default values
 	if h.ResponseTimeout < 1 {
-		h.ResponseTimeout = 1
+		h.ResponseTimeout = 10
 	}
 	// Check send and expected string
 	if h.Method == "" {