package influxdb import ( "encoding/json" "errors" "fmt" "net/http" "strings" "sync" "github.com/influxdata/telegraf/plugins/inputs" ) type InfluxDB struct { URLs []string `toml:"urls"` } func (*InfluxDB) Description() string { return "Read InfluxDB-formatted JSON metrics from one or more HTTP endpoints" } func (*InfluxDB) SampleConfig() string { return ` # Works with InfluxDB debug endpoints out of the box, # but other services can use this format too. # See the influxdb plugin's README for more details. # Multiple URLs from which to read InfluxDB-formatted JSON urls = [ "http://localhost:8086/debug/vars" ] ` } func (i *InfluxDB) Gather(acc inputs.Accumulator) error { errorChannel := make(chan error, len(i.URLs)) var wg sync.WaitGroup for _, u := range i.URLs { wg.Add(1) go func(url string) { defer wg.Done() if err := i.gatherURL(acc, url); err != nil { errorChannel <- fmt.Errorf("[url=%s]: %s", url, err) } }(u) } wg.Wait() close(errorChannel) // If there weren't any errors, we can return nil now. if len(errorChannel) == 0 { return nil } // There were errors, so join them all together as one big error. errorStrings := make([]string, 0, len(errorChannel)) for err := range errorChannel { errorStrings = append(errorStrings, err.Error()) } return errors.New(strings.Join(errorStrings, "\n")) } type point struct { Name string `json:"name"` Tags map[string]string `json:"tags"` Values map[string]interface{} `json:"values"` } // Gathers data from a particular URL // Parameters: // acc : The telegraf Accumulator to use // url : endpoint to send request to // // Returns: // error: Any error that may have occurred func (i *InfluxDB) gatherURL( acc inputs.Accumulator, url string, ) error { resp, err := http.Get(url) if err != nil { return err } defer resp.Body.Close() // It would be nice to be able to decode into a map[string]point, but // we'll get a decoder error like: // `json: cannot unmarshal array into Go value of type influxdb.point` // if any of the values aren't objects. // To avoid that error, we decode by hand. dec := json.NewDecoder(resp.Body) // Parse beginning of object if t, err := dec.Token(); err != nil { return err } else if t != json.Delim('{') { return errors.New("document root must be a JSON object") } // Loop through rest of object for { // Nothing left in this object, we're done if !dec.More() { break } // Read in a string key. We don't do anything with the top-level keys, so it's discarded. _, err := dec.Token() if err != nil { return err } // Attempt to parse a whole object into a point. // It might be a non-object, like a string or array. // If we fail to decode it into a point, ignore it and move on. var p point if err := dec.Decode(&p); err != nil { continue } // If the object was a point, but was not fully initialized, ignore it and move on. if p.Name == "" || p.Tags == nil || p.Values == nil || len(p.Values) == 0 { continue } // Add a tag to indicate the source of the data. p.Tags["url"] = url acc.AddFields( p.Name, p.Values, p.Tags, ) } return nil } func init() { inputs.Add("influxdb", func() inputs.Input { return &InfluxDB{} }) }