http_response: match on status code (#8032)

plugins/inputs/http_response/README.md

@@ -51,6 +51,12 @@ This input plugin checks HTTP/HTTPS connections.
   # response_string_match = "ok"
   # response_string_match = "\".*_status\".?:.?\"up\""
 
+  ## Expected response status code.
+  ## The status code of the response is compared to this value. If they match, the field
+  ## "response_status_code_match" will be 1, otherwise it will be 0. If the
+  ## expected status code is 0, the check is disabled and the field won't be added.
+  # response_status_code = 0
+
   ## Optional TLS Config
   # tls_ca = "/etc/telegraf/ca.pem"
   # tls_cert = "/etc/telegraf/cert.pem"
@@ -83,6 +89,7 @@ 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))
@@ -94,13 +101,14 @@ 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|
+|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

@@ -42,6 +42,7 @@ type HTTPResponse struct {
 	ResponseBodyField   string        `toml:"response_body_field"`
 	ResponseBodyMaxSize internal.Size `toml:"response_body_max_size"`
 	ResponseStringMatch string
+	ResponseStatusCode  int
 	Interface           string
 	// HTTP Basic Auth Credentials
 	Username string `toml:"username"`
@@ -106,6 +107,12 @@ var sampleConfig = `
   # response_string_match = "ok"
   # response_string_match = "\".*_status\".?:.?\"up\""
 
+  ## Expected response status code.
+  ## The status code of the response is compared to this value. If they match, the field
+  ## "response_status_code_match" will be 1, otherwise it will be 0. If the
+  ## expected status code is 0, the check is disabled and the field won't be added.
+  # response_status_code = 0
+
   ## Optional TLS Config
   # tls_ca = "/etc/telegraf/ca.pem"
   # tls_cert = "/etc/telegraf/cert.pem"
@@ -214,6 +221,7 @@ func setResult(result_string string, fields map[string]interface{}, tags map[str
 		"connection_failed":             3,
 		"timeout":                       4,
 		"dns_error":                     5,
+		"response_status_code_mismatch": 6,
 	}
 
 	tags["result"] = result_string
@@ -352,16 +360,31 @@ func (h *HTTPResponse) httpGather(u string) (map[string]interface{}, map[string]
 	}
 	fields["content_length"] = len(bodyBytes)
 
-	// Check the response for a regex match.
+	var success = true
+
+	// Check the response for a regex
 	if h.ResponseStringMatch != "" {
 		if h.compiledStringMatch.Match(bodyBytes) {
-			setResult("success", fields, tags)
 			fields["response_string_match"] = 1
 		} else {
+			success = false
 			setResult("response_string_mismatch", fields, tags)
 			fields["response_string_match"] = 0
 		}
+	}
+
+	// Check the response status code
+	if h.ResponseStatusCode > 0 {
+		if resp.StatusCode == h.ResponseStatusCode {
+			fields["response_status_code_match"] = 1
 		} else {
+			success = false
+			setResult("response_status_code_mismatch", fields, tags)
+			fields["response_status_code_match"] = 0
+		}
+	}
+
+	if success {
 		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 +1113,139 @@ 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",
+		ResponseStatusCode: 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",
+		ResponseStatusCode: 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)
+}
+
+func TestStatusCodeAndStringMatch(t *testing.T) {
+	mux := setUpTestMux()
+	ts := httptest.NewServer(mux)
+	defer ts.Close()
+
+	h := &HTTPResponse{
+		Log:                 testutil.Logger{},
+		Address:             ts.URL + "/good",
+		ResponseStatusCode:  http.StatusOK,
+		ResponseStringMatch: "hit the good page",
+		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.StatusOK,
+		"response_status_code_match": 1,
+		"response_string_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": "200",
+		"result":      "success",
+	}
+	checkOutput(t, &acc, expectedFields, expectedTags, nil, nil)
+}
+
+func TestStatusCodeAndStringMatchFail(t *testing.T) {
+	mux := setUpTestMux()
+	ts := httptest.NewServer(mux)
+	defer ts.Close()
+
+	h := &HTTPResponse{
+		Log:                 testutil.Logger{},
+		Address:             ts.URL + "/nocontent",
+		ResponseStatusCode:  http.StatusOK,
+		ResponseStringMatch: "hit the good page",
+		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,
+		"response_string_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)
+}