# InfluxDB Listener Input Plugin

InfluxDB Listener is a service input plugin that listens for requests sent
according to the [InfluxDB HTTP API][influxdb_http_api].  The intent of the
plugin is to allow Telegraf to serve as a proxy/router for the `/write`
endpoint of the InfluxDB HTTP API.

**Note:** This plugin was previously known as `http_listener`.  If you wish to
send general metrics via HTTP it is recommended to use the
[`http_listener_v2`][http_listener_v2] instead.

The `/write` endpoint supports the `precision` query parameter and can be set
to one of `ns`, `u`, `ms`, `s`, `m`, `h`.  All other parameters are ignored and
defer to the output plugins configuration.

When chaining Telegraf instances using this plugin, CREATE DATABASE requests
receive a 200 OK response with message body `{"results":[]}` but they are not
relayed. The output configuration of the Telegraf instance which ultimately
submits data to InfluxDB determines the destination database.

## Service Input <!-- @/docs/includes/service_input.md -->

This plugin is a service input. Normal plugins gather metrics determined by the
interval setting. Service plugins start a service to listens and waits for
metrics or events to occur. Service plugins have two key differences from
normal plugins:

1. The global or plugin specific `interval` setting may not apply
2. The CLI options of `--test`, `--test-wait`, and `--once` may not produce
   output for this plugin

## Global configuration options <!-- @/docs/includes/plugin_config.md -->

In addition to the plugin-specific configuration settings, plugins support
additional global and plugin configuration settings. These settings are used to
modify metrics, tags, and field or create aliases and configure ordering, etc.
See the [CONFIGURATION.md][CONFIGURATION.md] for more details.

[CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins

## Configuration

```toml @sample.conf
# Accept metrics over InfluxDB 1.x HTTP API
[[inputs.influxdb_listener]]
  ## Address and port to host HTTP listener on
  service_address = ":8186"

  ## maximum duration before timing out read of the request
  read_timeout = "10s"
  ## maximum duration before timing out write of the response
  write_timeout = "10s"

  ## Maximum allowed HTTP request body size in bytes.
  ## 0 means to use the default of 32MiB.
  max_body_size = 0

  ## Maximum line size allowed to be sent in bytes.
  ##   deprecated in 1.14; parser now handles lines of unlimited length and option is ignored
  # max_line_size = 0

  ## Set one or more allowed client CA certificate file names to
  ## enable mutually authenticated TLS connections
  tls_allowed_cacerts = ["/etc/telegraf/clientca.pem"]

  ## Add service certificate and key
  tls_cert = "/etc/telegraf/cert.pem"
  tls_key = "/etc/telegraf/key.pem"

  ## Optional tag name used to store the database name.
  ## If the write has a database in the query string then it will be kept in this tag name.
  ## This tag can be used in downstream outputs.
  ## The default value of nothing means it will be off and the database will not be recorded.
  ## If you have a tag that is the same as the one specified below, and supply a database,
  ## the tag will be overwritten with the database supplied.
  # database_tag = ""

  ## If set the retention policy specified in the write query will be added as
  ## the value of this tag name.
  # retention_policy_tag = ""

  ## Optional username and password to accept for HTTP basic authentication.
  ## You probably want to make sure you have TLS configured above for this.
  # basic_username = "foobar"
  # basic_password = "barfoo"

  ## Influx line protocol parser
  ## 'internal' is the default. 'upstream' is a newer parser that is faster
  ## and more memory efficient.
  # parser_type = "internal"
```

## Metrics

Metrics are created from InfluxDB Line Protocol in the request body.

## Troubleshooting

**Example Query:**

```sh
curl -i -XPOST 'http://localhost:8186/write' --data-binary 'cpu_load_short,host=server01,region=us-west value=0.64 1434055562000000000'
```

[influxdb_http_api]: https://docs.influxdata.com/influxdb/v1.8/guides/write_data/
[http_listener_v2]: /plugins/inputs/http_listener_v2/README.md

## Example Output
