telegraf/plugins/influxdb/influxdb.go

151 lines
3.4 KiB
Go

package influxdb
import (
"encoding/json"
"errors"
"fmt"
"net/http"
"strings"
"sync"
"github.com/influxdb/telegraf/plugins"
)
type InfluxDB struct {
Name string
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 `
# Reads InfluxDB-formatted JSON from given URLs.
# 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.
[[plugins.influxdb]]
# Name to use for measurement
name = "influxdb"
# Multiple URLs from which to read InfluxDB-formatted JSON
urls = [
"http://localhost:8086/debug/vars"
]
`
}
func (i *InfluxDB) Gather(acc plugins.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("[name=%s][url=%s]: %s", i.Name, 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 plugins.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(
i.Name+"_"+p.Name,
p.Values,
p.Tags,
)
}
return nil
}
func init() {
plugins.Add("influxdb", func() plugins.Plugin {
return &InfluxDB{}
})
}