# Graylog Output Plugin

This plugin writes to a Graylog instance using the "[GELF][]" format.

[GELF]: https://docs.graylog.org/en/3.1/pages/gelf.html#gelf-payload-specification

## GELF Fields

The [GELF spec][] spec defines a number of specific fields in a GELF payload.
These fields may have specific requirements set by the spec and users of the
Graylog plugin need to follow these requirements or metrics may be rejected due
to invalid data.

For example, the timestamp field defined in the GELF spec, is required to be a
UNIX timestamp. This output plugin will not modify or check the timestamp field
if one is present and send it as-is to Graylog. If the field is absent then
Telegraf will set the timestamp to the current time.

Any field not defined by the spec will have an underscore (e.g. `_`) prefixed to
the field name.

[GELF spec]: https://docs.graylog.org/docs/gelf#gelf-payload-specification

## Configuration

```toml @sample.conf
# Send telegraf metrics to graylog
[[outputs.graylog]]
  ## Endpoints for your graylog instances.
  servers = ["udp://127.0.0.1:12201"]

  ## Connection timeout.
  # timeout = "5s"

  ## The field to use as the GELF short_message, if unset the static string
  ## "telegraf" will be used.
  ##   example: short_message_field = "message"
  # short_message_field = ""

  ## According to GELF payload specification, additional fields names must be prefixed
  ## with an underscore. Previous versions did not prefix custom field 'name' with underscore.
  ## Set to true for backward compatibility.
  # name_field_no_prefix = false

  ## Optional TLS Config
  # tls_ca = "/etc/telegraf/ca.pem"
  # tls_cert = "/etc/telegraf/cert.pem"
  # tls_key = "/etc/telegraf/key.pem"
  ## Use TLS but skip chain & host verification
  # insecure_skip_verify = false
```

Server endpoint may be specified without UDP or TCP scheme
(eg. "127.0.0.1:12201").  In such case, UDP protocol is assumed. TLS config is
ignored for UDP endpoints.
