adds fake response for telegraph queries (#1130)

https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1124

app/vmagent/README.md

@@ -515,6 +515,7 @@ See the docs at https://victoriametrics.github.io/vmagent.html .
   -import.maxLineLen max_rows_per_line
     	The maximum length in bytes of a single line accepted by /api/v1/import; the line length can be limited with max_rows_per_line query arg passed to /api/v1/export
     	Supports the following optional suffixes for values: KB, MB, GB, KiB, MiB, GiB (default 104857600)
+  -influx.databasesNames comma separated names of influx database, that will be returned for /query and /influx/query request.
   -influx.maxLineSize value
     	The maximum size in bytes for a single Influx line during parsing
     	Supports the following optional suffixes for values: KB, MB, GB, KiB, MiB, GiB (default 262144)

app/vmagent/main.go

@@ -49,6 +49,7 @@ var (
 	dryRun                 = flag.Bool("dryRun", false, "Whether to check only config files without running vmagent. The following files are checked: "+
 		"-promscrape.config, -remoteWrite.relabelConfig, -remoteWrite.urlRelabelConfig . "+
 		"Unknown config entries are allowed in -promscrape.config by default. This can be changed with -promscrape.config.strictParse")
+	influxDatabasesNames = flag.String("influx.databasesNames", "_internal", "Comma separated names of databases, that will be returned for /query and /influx/query api.")
 )
 
 var (
@@ -205,9 +206,17 @@ func requestHandler(w http.ResponseWriter, r *http.Request) bool {
 		return true
 	case "/query":
 		// Emulate fake response for influx query.
-		// This is required for TSBS benchmark.
+		// This is required for TSBS benchmark and some telegraph plugins.
 		influxQueryRequests.Inc()
-		fmt.Fprintf(w, `{"results":[{"series":[{"values":[]}]}]}`)
+		var dbs string
+		influxDbs := strings.Split(*influxDatabasesNames, ",")
+		for i := range influxDbs {
+			dbs += fmt.Sprintf(`"[%s]"`, influxDbs[i])
+			if i != len(influxDbs)-1 {
+				dbs += ","
+			}
+		}
+		fmt.Fprintf(w, `{"results":[{"name":"databases","columns":["name"],"series":[{"values":[%s]}]}]}`, dbs)
 		return true
 	case "/targets":
 		promscrapeTargetsRequests.Inc()

app/vminsert/main.go

@@ -40,6 +40,7 @@ var (
 		"Usually :4242 must be set. Doesn't work if empty")
 	opentsdbHTTPListenAddr = flag.String("opentsdbHTTPListenAddr", "", "TCP address to listen for OpentTSDB HTTP put requests. Usually :4242 must be set. Doesn't work if empty")
 	maxLabelsPerTimeseries = flag.Int("maxLabelsPerTimeseries", 30, "The maximum number of labels accepted per time series. Superfluous labels are dropped")
+	influxDatabasesNames   = flag.String("influx.databasesNames", "_internal", "Comma separated names of databases, that will be returned for /query and /influx/query api.")
 )
 
 var (
@@ -148,9 +149,17 @@ func RequestHandler(w http.ResponseWriter, r *http.Request) bool {
 		return true
 	case "/influx/query", "/query":
 		// Emulate fake response for influx query.
-		// This is required for TSBS benchmark.
+		// This is required for TSBS benchmark and some telegraph plugins.
 		influxQueryRequests.Inc()
-		fmt.Fprintf(w, `{"results":[{"series":[{"values":[]}]}]}`)
+		var dbs string
+		influxDbs := strings.Split(*influxDatabasesNames, ",")
+		for i := range influxDbs {
+			dbs += fmt.Sprintf(`"[%s]"`, influxDbs[i])
+			if i != len(influxDbs)-1 {
+				dbs += ","
+			}
+		}
+		fmt.Fprintf(w, `{"results":[{"name":"databases","columns":["name"],"series":[{"values":[%s]}]}]}`, dbs)
 		return true
 	case "/prometheus/targets", "/targets":
 		promscrapeTargetsRequests.Inc()

docs/vmagent.md

@@ -515,6 +515,7 @@ See the docs at https://victoriametrics.github.io/vmagent.html .
   -import.maxLineLen max_rows_per_line
     	The maximum length in bytes of a single line accepted by /api/v1/import; the line length can be limited with max_rows_per_line query arg passed to /api/v1/export
     	Supports the following optional suffixes for values: KB, MB, GB, KiB, MiB, GiB (default 104857600)
+  -influx.databasesNames comma separated names of influx database, that will be returned for /query and /influx/query request.
   -influx.maxLineSize value
     	The maximum size in bytes for a single Influx line during parsing
     	Supports the following optional suffixes for values: KB, MB, GB, KiB, MiB, GiB (default 262144)