Add database_tag option to influxdb_listener to add database from query string (#6257)

plugins/inputs/influxdb_listener/README.md

@@ -46,6 +46,14 @@ submits data to InfluxDB determines the destination database.
   tls_cert = "/etc/telegraf/cert.pem"
   tls_key = "/etc/telegraf/key.pem"
 
+  ## Optional tag name used to store the database name.
+  ## If the write has a database in the query string then it will be kept in this tag name.
+  ## This tag can be used in downstream outputs.
+  ## The default value of nothing means it will be off and the database will not be recorded.
+  ## If you have a tag that is the same as the one specified below, and supply a database,
+  ## the tag will be overwritten with the database supplied.
+  # database_tag = ""
+
   ## Optional username and password to accept for HTTP basic authentication.
   ## You probably want to make sure you have TLS configured above for this.
   # basic_username = "foobar"

plugins/inputs/influxdb_listener/http_listener.go

@@ -37,17 +37,18 @@ const (
 type TimeFunc func() time.Time
 
 type HTTPListener struct {
-	ServiceAddress string
-	ReadTimeout    internal.Duration
-	WriteTimeout   internal.Duration
-	MaxBodySize    internal.Size
-	MaxLineSize    internal.Size
-	Port           int
-
+	ServiceAddress string `toml:"service_address"`
+	// Port gets pulled out of ServiceAddress
+	Port int
 	tlsint.ServerConfig
 
-	BasicUsername string
-	BasicPassword string
+	ReadTimeout   internal.Duration `toml:"read_timeout"`
+	WriteTimeout  internal.Duration `toml:"write_timeout"`
+	MaxBodySize   internal.Size     `toml:"max_body_size"`
+	MaxLineSize   internal.Size     `toml:"max_line_size"`
+	BasicUsername string            `toml:"basic_username"`
+	BasicPassword string            `toml:"basic_password"`
+	DatabaseTag   string            `toml:"database_tag"`
 
 	TimeFunc
 
@@ -93,6 +94,13 @@ const sampleConfig = `
   ## Maximum line size allowed to be sent in bytes.
   ## 0 means to use the default of 65536 bytes (64 kibibytes)
   max_line_size = "64KiB"
+  
+
+  ## Optional tag name used to store the database. 
+  ## If the write has a database in the query string then it will be kept in this tag name.
+  ## This tag can be used in downstream outputs.
+  ## The default value of nothing means it will be off and the database will not be recorded.
+  # database_tag = ""
 
   ## Set one or more allowed client CA certificate file names to
   ## enable mutually authenticated TLS connections
@@ -258,6 +266,7 @@ func (h *HTTPListener) serveWrite(res http.ResponseWriter, req *http.Request) {
 	now := h.TimeFunc()
 
 	precision := req.URL.Query().Get("precision")
+	db := req.URL.Query().Get("db")
 
 	// Handle gzip request bodies
 	body := req.Body
@@ -315,7 +324,7 @@ func (h *HTTPListener) serveWrite(res http.ResponseWriter, req *http.Request) {
 
 		if err == io.ErrUnexpectedEOF {
 			// finished reading the request body
-			err = h.parse(buf[:n+bufStart], now, precision)
+			err = h.parse(buf[:n+bufStart], now, precision, db)
 			if err != nil {
 				log.Println("D! "+err.Error(), bufStart+n)
 				return400 = true
@@ -346,7 +355,7 @@ func (h *HTTPListener) serveWrite(res http.ResponseWriter, req *http.Request) {
 			bufStart = 0
 			continue
 		}
-		if err := h.parse(buf[:i+1], now, precision); err != nil {
+		if err := h.parse(buf[:i+1], now, precision, db); err != nil {
 			log.Println("D! " + err.Error())
 			return400 = true
 		}
@@ -359,7 +368,7 @@ func (h *HTTPListener) serveWrite(res http.ResponseWriter, req *http.Request) {
 	}
 }
 
-func (h *HTTPListener) parse(b []byte, t time.Time, precision string) error {
+func (h *HTTPListener) parse(b []byte, t time.Time, precision, db string) error {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
@@ -371,6 +380,13 @@ func (h *HTTPListener) parse(b []byte, t time.Time, precision string) error {
 	}
 
 	for _, m := range metrics {
+		// Do we need to keep the database name in the query string.
+		// If a tag has been supplied to put the db in and we actually got a db query,
+		// then we write it in. This overwrites the database tag if one was sent.
+		// This makes it behave like the influx endpoint.
+		if h.DatabaseTag != "" && db != "" {
+			m.AddTag(h.DatabaseTag, db)
+		}
 		h.acc.AddFields(m.Name(), m.Fields(), m.Tags(), m.Time())
 	}
 

plugins/inputs/influxdb_listener/http_listener_test.go

@@ -146,8 +146,11 @@ func TestWriteHTTPBasicAuth(t *testing.T) {
 	require.EqualValues(t, http.StatusNoContent, resp.StatusCode)
 }
 
-func TestWriteHTTP(t *testing.T) {
+func TestWriteHTTPKeepDatabase(t *testing.T) {
+	testMsgWithDB := "cpu_load_short,host=server01,database=wrongdb value=12.0 1422568543702900257\n"
+
 	listener := newTestHTTPListener()
+	listener.DatabaseTag = "database"
 
 	acc := &testutil.Accumulator{}
 	require.NoError(t, listener.Start(acc))
@@ -162,7 +165,19 @@ func TestWriteHTTP(t *testing.T) {
 	acc.Wait(1)
 	acc.AssertContainsTaggedFields(t, "cpu_load_short",
 		map[string]interface{}{"value": float64(12)},
-		map[string]string{"host": "server01"},
+		map[string]string{"host": "server01", "database": "mydb"},
+	)
+
+	// post single message to listener with a database tag in it already. It should be clobbered.
+	resp, err = http.Post(createURL(listener, "http", "/write", "db=mydb"), "", bytes.NewBuffer([]byte(testMsgWithDB)))
+	require.NoError(t, err)
+	resp.Body.Close()
+	require.EqualValues(t, 204, resp.StatusCode)
+
+	acc.Wait(1)
+	acc.AssertContainsTaggedFields(t, "cpu_load_short",
+		map[string]interface{}{"value": float64(12)},
+		map[string]string{"host": "server01", "database": "mydb"},
 	)
 
 	// post multiple message to listener
@@ -177,21 +192,9 @@ func TestWriteHTTP(t *testing.T) {
 	for _, hostTag := range hostTags {
 		acc.AssertContainsTaggedFields(t, "cpu_load_short",
 			map[string]interface{}{"value": float64(12)},
-			map[string]string{"host": hostTag},
+			map[string]string{"host": hostTag, "database": "mydb"},
 		)
 	}
-
-	// Post a gigantic metric to the listener and verify that an error is returned:
-	resp, err = http.Post(createURL(listener, "http", "/write", "db=mydb"), "", bytes.NewBuffer([]byte(hugeMetric)))
-	require.NoError(t, err)
-	resp.Body.Close()
-	require.EqualValues(t, 400, resp.StatusCode)
-
-	acc.Wait(3)
-	acc.AssertContainsTaggedFields(t, "cpu_load_short",
-		map[string]interface{}{"value": float64(12)},
-		map[string]string{"host": "server01"},
-	)
 }
 
 // http listener should add a newline at the end of the buffer if it's not there