http_response: status_code match

plugins/inputs/http_response/README.md

@@ -45,6 +45,9 @@ This input plugin checks HTTP/HTTPS connections.
   # response_string_match = "ok"
   # response_string_match = "\".*_status\".?:.?\"up\""
 
+  ## Optional status code match of the response
+  # response_status_code_match = 204
+
   ## Optional TLS Config
   # tls_ca = "/etc/telegraf/ca.pem"
   # tls_cert = "/etc/telegraf/cert.pem"
@@ -77,6 +80,7 @@ This input plugin checks HTTP/HTTPS connections.
     - response_time (float, seconds)
     - content_length (int, response body length)
     - response_string_match (int, 0 = mismatch / body read error, 1 = match)
+    - response_status_code_match (int, 0 = mismatch, 1 = match)
     - http_response_code (int, response status code)
 	- result_type (string, deprecated in 1.6: use `result` tag and `result_code` field)
     - result_code (int, [see below](#result--result_code))
@@ -87,14 +91,15 @@ Upon finishing polling the target server, the plugin registers the result of the
 
 This tag is used to expose network and plugin errors. HTTP errors are considered a successful connection.
 
-|Tag value                |Corresponding field value|Description|
---------------------------|-------------------------|-----------|
-|success                  | 0                       |The HTTP request completed, even if the HTTP code represents an error|
-|response_string_mismatch | 1                       |The option `response_string_match` was used, and the body of the response didn't match the regex. HTTP errors with content in their body (like 4xx, 5xx) will trigger this error|
-|body_read_error          | 2                       |The option `response_string_match` was used, but the plugin wasn't able to read the body of the response. Responses with empty bodies (like 3xx, HEAD, etc) will trigger this error. Or the option `response_body_field` was used and the content of the response body was not a valid utf-8. Or the size of the body of the response exceeded the `response_body_max_size` |
-|connection_failed        | 3                       |Catch all for any network error not specifically handled by the plugin|
-|timeout                  | 4                       |The plugin timed out while awaiting the HTTP connection to complete|
-|dns_error                | 5                       |There was a DNS error while attempting to connect to the host|
+|Tag value                     |Corresponding field value|Description|
+-------------------------------|-------------------------|-----------|
+|success                       | 0                       |The HTTP request completed, even if the HTTP code represents an error|
+|response_string_mismatch      | 1                       |The option `response_string_match` was used, and the body of the response didn't match the regex. HTTP errors with content in their body (like 4xx, 5xx) will trigger this error|
+|body_read_error               | 2                       |The option `response_string_match` was used, but the plugin wasn't able to read the body of the response. Responses with empty bodies (like 3xx, HEAD, etc) will trigger this error. Or the option `response_body_field` was used and the content of the response body was not a valid utf-8. Or the size of the body of the response exceeded the `response_body_max_size` |
+|connection_failed             | 3                       |Catch all for any network error not specifically handled by the plugin|
+|timeout                       | 4                       |The plugin timed out while awaiting the HTTP connection to complete|
+|dns_error                     | 5                       |There was a DNS error while attempting to connect to the host|
+|response_status_code_mismatch | 6                       |The option `response_status_code_match` was used, and the status code of the response didn't match the value.|
 
 
 ### Example Output:

plugins/inputs/http_response/http_response.go

@@ -38,11 +38,12 @@ type HTTPResponse struct {
 	Headers         map[string]string
 	FollowRedirects bool
 	// Absolute path to file with Bearer token
-	BearerToken         string        `toml:"bearer_token"`
-	ResponseBodyField   string        `toml:"response_body_field"`
-	ResponseBodyMaxSize internal.Size `toml:"response_body_max_size"`
-	ResponseStringMatch string
-	Interface           string
+	BearerToken             string        `toml:"bearer_token"`
+	ResponseBodyField       string        `toml:"response_body_field"`
+	ResponseBodyMaxSize     internal.Size `toml:"response_body_max_size"`
+	ResponseStringMatch     string
+	ResponseStatusCodeMatch int
+	Interface               string
 	// HTTP Basic Auth Credentials
 	Username string `toml:"username"`
 	Password string `toml:"password"`
@@ -106,6 +107,9 @@ var sampleConfig = `
   # response_string_match = "ok"
   # response_string_match = "\".*_status\".?:.?\"up\""
 
+  ## Optional status code match of the response
+  # response_status_code_match = 204
+
   ## Optional TLS Config
   # tls_ca = "/etc/telegraf/ca.pem"
   # tls_cert = "/etc/telegraf/cert.pem"
@@ -208,12 +212,13 @@ func localAddress(interfaceName string) (net.Addr, error) {
 
 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,
+		"success":                       0,
+		"response_string_mismatch":      1,
+		"body_read_error":               2,
+		"connection_failed":             3,
+		"timeout":                       4,
+		"dns_error":                     5,
+		"response_status_code_mismatch": 6,
 	}
 
 	tags["result"] = result_string
@@ -352,7 +357,7 @@ func (h *HTTPResponse) httpGather(u string) (map[string]interface{}, map[string]
 	}
 	fields["content_length"] = len(bodyBytes)
 
-	// Check the response for a regex match.
+	// Check the response for a regex or status code match.
 	if h.ResponseStringMatch != "" {
 		if h.compiledStringMatch.Match(bodyBytes) {
 			setResult("success", fields, tags)
@@ -361,6 +366,14 @@ func (h *HTTPResponse) httpGather(u string) (map[string]interface{}, map[string]
 			setResult("response_string_mismatch", fields, tags)
 			fields["response_string_match"] = 0
 		}
+	} else if h.ResponseStatusCodeMatch > 0 {
+		if resp.StatusCode == h.ResponseStatusCodeMatch {
+			setResult("success", fields, tags)
+			fields["response_status_code_match"] = 1
+		} else {
+			setResult("response_status_code_mismatch", fields, tags)
+			fields["response_status_code_match"] = 0
+		}
 	} else {
 		setResult("success", fields, tags)
 	}

plugins/inputs/http_response/http_response_test.go

@@ -126,6 +126,9 @@ func setUpTestMux() http.Handler {
 		time.Sleep(time.Second * 2)
 		return
 	})
+	mux.HandleFunc("/nocontent", func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusNoContent)
+	})
 	return mux
 }
 
@@ -1110,3 +1113,69 @@ func TestBasicAuth(t *testing.T) {
 	absentFields := []string{"response_string_match"}
 	checkOutput(t, &acc, expectedFields, expectedTags, absentFields, nil)
 }
+
+func TestStatusCodeMatchFail(t *testing.T) {
+	mux := setUpTestMux()
+	ts := httptest.NewServer(mux)
+	defer ts.Close()
+
+	h := &HTTPResponse{
+		Log:                     testutil.Logger{},
+		Address:                 ts.URL + "/nocontent",
+		ResponseStatusCodeMatch: http.StatusOK,
+		ResponseTimeout:         internal.Duration{Duration: time.Second * 20},
+	}
+
+	var acc testutil.Accumulator
+	err := h.Gather(&acc)
+	require.NoError(t, err)
+
+	expectedFields := map[string]interface{}{
+		"http_response_code":         http.StatusNoContent,
+		"response_status_code_match": 0,
+		"result_type":                "response_status_code_mismatch",
+		"result_code":                6,
+		"response_time":              nil,
+		"content_length":             nil,
+	}
+	expectedTags := map[string]interface{}{
+		"server":      nil,
+		"method":      http.MethodGet,
+		"status_code": "204",
+		"result":      "response_status_code_mismatch",
+	}
+	checkOutput(t, &acc, expectedFields, expectedTags, nil, nil)
+}
+
+func TestStatusCodeMatch(t *testing.T) {
+	mux := setUpTestMux()
+	ts := httptest.NewServer(mux)
+	defer ts.Close()
+
+	h := &HTTPResponse{
+		Log:                     testutil.Logger{},
+		Address:                 ts.URL + "/nocontent",
+		ResponseStatusCodeMatch: http.StatusNoContent,
+		ResponseTimeout:         internal.Duration{Duration: time.Second * 20},
+	}
+
+	var acc testutil.Accumulator
+	err := h.Gather(&acc)
+	require.NoError(t, err)
+
+	expectedFields := map[string]interface{}{
+		"http_response_code":         http.StatusNoContent,
+		"response_status_code_match": 1,
+		"result_type":                "success",
+		"result_code":                0,
+		"response_time":              nil,
+		"content_length":             nil,
+	}
+	expectedTags := map[string]interface{}{
+		"server":      nil,
+		"method":      http.MethodGet,
+		"status_code": "204",
+		"result":      "success",
+	}
+	checkOutput(t, &acc, expectedFields, expectedTags, nil, nil)
+}