telegraf/plugins/inputs/multifile/README.md

# Multifile Input Plugin

The multifile input plugin allows Telegraf to combine data from multiple files
into a single metric, creating one field or tag per file.  This is often
useful creating custom metrics from the `/sys` or `/proc` filesystems.

> Note: If you wish to parse metrics from a single file formatted in one of the supported
> [input data formats][], you should use the [file][] input plugin instead.

### Configuration
```toml
[[inputs.multifile]]
  ## Base directory where telegraf will look for files.
  ## Omit this option to use absolute paths.
  base_dir = "/sys/bus/i2c/devices/1-0076/iio:device0"

  ## If true discard all data when a single file can't be read.
  ## Else, Telegraf omits the field generated from this file.
  # fail_early = true

  ## Files to parse each interval.
  [[inputs.multifile.file]]
    file = "in_pressure_input"
    dest = "pressure"
    conversion = "float"
  [[inputs.multifile.file]]
    file = "in_temp_input"
    dest = "temperature"
    conversion = "float(3)"
  [[inputs.multifile.file]]
    file = "in_humidityrelative_input"
    dest = "humidityrelative"
    conversion = "float(3)"
```

Each file table can contain the following options:
* `file`:
Path of the file to be parsed, relative to the `base_dir`.
* `dest`:
Name of the field/tag key, defaults to `$(basename file)`.
* `conversion`:
Data format used to parse the file contents:
	* `float(X)`: Converts the input value into a float and divides by the Xth power of 10. Efficively just moves the decimal left X places. For example a value of `123` with `float(2)` will result in `1.23`.
	* `float`: Converts the value into a float with no adjustment. Same as `float(0)`.
	* `int`: Convertes the value into an integer.
	* `string`, `""`: No conversion.
	* `bool`: Convertes the value into a boolean.
	* `tag`: File content is used as a tag.

### Example Output
This example shows a BME280 connected to a Raspberry Pi, using the sample config.
```
multifile pressure=101.343285156,temperature=20.4,humidityrelative=48.9 1547202076000000000
```

To reproduce this, connect a BMP280 to the board's GPIO pins and register the BME280 device driver
```
cd /sys/bus/i2c/devices/i2c-1
echo bme280 0x76 > new_device
```

The kernel driver provides the following files in `/sys/bus/i2c/devices/1-0076/iio:device0`:
* `in_humidityrelative_input`: `48900`
* `in_pressure_input`: `101.343285156`
* `in_temp_input`: `20400`

[input data formats]: /docs/DATA_FORMATS_INPUT.md
[file]: /plugins/inputs/file/README.md