# Configuration

The main configuration lives in `monitor.ini`. By default, SimpleMonitor will look for it in the working directory when launched. To specify a different file, use the `-f` option.

The format is fairly standard “INI”; section names are lowercase in `[square brackets]`, and values inside the sections are defined as `key=value`. You can use blank lines to space things out, and comments start with `#`.

Section names and option values, but not option names, support environment variable injection. To include the value of an environment variable, use `%env:VARIABLE%`, which will inject the value of `$VARAIBLE` from the environment. You can use this to share a common configuration file across multiple hosts, for example.

This main configuration file contains the global settings for SimpleMonitor, plus the logging and alerting configuration. A separate file, by default `monitors.ini`, contains the monitor configuration. You can specify a different monitors configuration file using a directive in the main configuration.

Warning

I know the configuration file names are dumb, sorry.

## Configuration value types

Values which take bool accept `1`, `yes`, and `true` as truthy, and everything else as falsey.

Values which take bytes accept suffixes of `K`, `M`, or `G` for kibibytes, mibibytes or gibibytes, otherwise are just a number of bytes.

## `monitor.ini`

This file must contain a `[monitor]` section, which must contain at least the `interval` setting.

### `[monitor]` section

interval
  Type:

    integer

  Required:

    true

  defines how many seconds to wait between running all the monitors. Note that the time taken to run the monitors is not subtracted from the interval, so the next iteration will run at interval + time_to_run_monitors seconds.

monitors
  Type:

    string

  Required:

    false

  Default:

    `monitors.ini`

  the filename to load the monitors themselves from. Relative to the cwd, not the path of this configuration file.

  If you want to use only `monitors_dir`, set this to nothing (`monitors=`).

monitors_dir
  Type:

    string

  Required:

    false

  a directory to scan for `*.ini` files which are merged with the main monitors config file. Files are loaded in lexicographic order, and if a monitor name is reused, the last definition wins. Relative to the cwd, not the path of this configuration file.

  The main `monitors` file is always loaded first.

pidfile
  Type:

    string

  Required:

    false

  Default:

    none

  the path to write a pidfile to.

remote
  Type:

    bool

  Required:

    false

  Default:

    false

  enables the listener for receiving data from remote instances. Can be overridden to disabled with `-N` command line option.

remote_port
  Type:

    integer

  Required:

    if `remote` is enabled

  the TCP port to listen on for remote data

key
  Type:

    string

  Required:

    if `remote` is enabled

  shared secret for validating data from remote instances.

bind_host
  Type:

    string

  Required:

    false

  Default:

    `0.0.0.0` (all interfaces)

  the local IP address to listen on, if `remote` is enabled.

hup_file
  Type:

    string

  Required:

    false

  Default:

    none

  a file to watch the modification time on. If the modification time increases, SimpleMonitor reloads its configuration.

  Tip

  SimpleMonitor will reload if it receives SIGHUP; this option is useful for platforms which don’t have that.

bind_host
  Type:

    string

  Required:

    false

  Default:

    all interfaces

  the local address to bind to for remote data

### `[reporting]` section

loggers
  Type:

    comma-separated list of string

  Required:

    false

  Default:

    none

  the names of the loggers you want to use. Each one must be a `[section]` in this configuration file.

  See Loggers for the common options and list of Alerters with their configurations.

alerters
  Type:

    comma-separated list of string

  Required:

    false

  Default:

    none

  the names of the alerters you want to use. Each one must be a `[section]` in this configuration file.

  See Alerters for the common options and list of Alerters with their configurations.

## `monitors.ini`

This file only contains monitors. Each monitor is a `[section]` in the file, with the section name giving the monitor its name. The name `defaults` is reserved, and can be used to specify default values for options. Each monitor’s individual configuration overrides the defaults.

See Monitors for the common options and list of Monitors with their configurations.

## Example configuration

This is an example pair of configuration files to show what goes where. For more examples, see Config examples.

`monitor.ini`:

    [monitor]
    interval=60

    [reporting]
    loggers=logfile
    alerters=email,sms

    # write a log file with the state of each monitor, each time
    [logfile]
    type=logfile
    filename=monitor.log

    # email me when monitors fail or succeed
    [email]
    type=email
    host=mailserver.example.com
    from=monitor@example.com
    to=admin@example.com

    # send me an SMS after a monitor has failed 10 times in a row
    [sms]
    type=bulksms
    username=some-username
    password=some-password
    target=+447777123456
    limit=10

`monitors.ini`:

    # check the webserver pings
    [www-ping]
    type=ping
    host=www.example.com

    # check the webserver answers https; don't bother checking if it's not pinging
    [www-http]
    type=http
    url=https://www.example.com
    depend=www-ping

    # check the root partition has at least 1GB of free space
    [root-diskspace]
    type=diskspace
    partition=/
    limit=1G

## Reloading

You can send SimpleMonitor a SIGHUP to make it reload its configuration. On platforms which don’t have that (e.g. Windows), you can specify a file to watch. If the modification time of the file changes, SimpleMonitor will reload its configuration.

Reloading will pick up a change to `interval` but no other configuration in the `[monitor]` section. Monitors, Alerters and Loggers are reloaded. You can add and remove them, and change their configurations, but not change their types. (To change a type, first remove it from the configuration and reload, then add it back in.)