This was primarily intended to consume InfluxDB-style expvars,
particularly InfluxDB's `/debug/vars` endpoint.
That endpoint follows a structure like
```json
{
"httpd::8086": {
"name": "httpd",
"tags": {
"bind": ":8086"
},
"values": {
"pointsWrittenOK": 33756,
"queryReq": 19,
"queryRespBytes": 26973,
"req": 428,
"writeReq": 205,
"writeReqBytes": 3939161
}
}
}
```
There are an arbitrary number of top-level keys in the JSON response at
the configured URLs, and this plugin will iterate through all of their
values looking for objects with keys "name", "tags", and "values"
indicating a metric to be consumed by telegraf.
Running this on current master of InfluxDB, I am able to record nearly
the same information that is normally stored in the `_internal`
database; the only measurement missing from `_internal` is `runtime`,
which is present in expvars under the "memstats" key but does not follow
the expvar format and so is not consumed in this plugin.
```
$ influx -database=telegraf -execute 'SHOW FIELD KEYS FROM /expvar/'
name: expvar_influxdb_engine
----------------------------
fieldKey
blksWrite
blksWriteBytes
blksWriteBytesC
pointsWrite
pointsWriteDedupe
name: expvar_influxdb_httpd
---------------------------
fieldKey
pingReq
pointsWrittenOK
queryReq
queryRespBytes
req
writeReq
writeReqBytes
name: expvar_influxdb_shard
---------------------------
fieldKey
fieldsCreate
seriesCreate
writePointsOk
writeReq
name: expvar_influxdb_subscriber
--------------------------------
fieldKey
pointsWritten
name: expvar_influxdb_wal
-------------------------
fieldKey
autoFlush
flushDuration
idleFlush
memSize
metaFlush
pointsFlush
pointsWrite
pointsWriteReq
seriesFlush
name: expvar_influxdb_write
---------------------------
fieldKey
pointReq
pointReqLocal
req
subWriteOk
writeOk
```
And unit test it using a sample response string. This will make it
easier to see what other metrics are available to the plugin for adding
future metrics.
"Devices" can be used to specify storage devices on which stats
should be reported. "SkipSerialNumber" can be used to omit
the device serial number.
Added tests to verify the new parameters.
closes#344
Mark Rushakoff
Cameron Sparr
Nathaniel Cook
Carlos J. Torres
Mischa Gresser
Regan Kuchan
Daniel Malon
Tait Clarridge
Tero Marttila
Eduard Carreras
Codeb Fan
鲁晓敏
Nicholas Katsaros
Roman Statsevich
Subhachandra Chandra
saiello
Simone Aiello
cornerot
Eugene Dementiev