Exec input plugin
editExec input plugin
edit- Plugin version: v3.3.3
- Released on: 2019-09-10
- Changelog
For other versions, see the Versioned plugin docs.
Installation
editFor plugins not bundled by default, it is easy to install by running bin/logstash-plugin install logstash-input-exec
. See Working with plugins for more details.
Getting Help
editFor questions about the plugin, open a topic in the Discuss forums. For bugs or feature requests, open an issue in Github. For the list of Elastic supported plugins, please consult the Elastic Support Matrix.
Description
editPeriodically run a shell command and capture the whole output as an event.
Notes:
-
The
command
field of this event will be the command run. -
The
message
field of this event will be the entire stdout of the command.
IMPORTANT
editThe exec input ultimately uses fork
to spawn a child process.
Using fork duplicates the parent process address space (in our case, logstash and the JVM); this is mitigated with OS copy-on-write but ultimately you can end up allocating lots of memory just for a "simple" executable.
If the exec input fails with errors like ENOMEM: Cannot allocate memory
it is an indication that there is not enough non-JVM-heap physical memory to perform the fork.
Example:
input { exec { command => "ls" interval => 30 } }
This will execute ls
command every 30 seconds.
Exec Input Configuration Options
editThis plugin supports the following configuration options plus the Common Options described later.
Also see Common Options for a list of options supported by all input plugins.
command
edit- This is a required setting.
- Value type is string
- There is no default value for this setting.
Command to run. For example, uptime
interval
edit- Value type is number
- There is no default value for this setting.
Interval to run the command. Value is in seconds.
Either interval
or schedule
option must be defined.
schedule
edit- Value type is string
- There is no default value for this setting.
Schedule of when to periodically run command.
This scheduling syntax is powered by rufus-scheduler. The syntax is cron-like with some extensions specific to Rufus (e.g. timezone support).
Examples:
|
will execute every minute of 5am every day of January through March. |
|
will execute on the 0th minute of every hour every day. |
|
will execute at 6:00am (UTC/GMT -5) every day. |
Further documentation describing this syntax can be found here.
Either interval
or schedule
option must be defined.
Common Options
editThe following configuration options are supported by all input plugins:
Details
edit
codec
edit- Value type is codec
-
Default value is
"plain"
The codec used for input data. Input codecs are a convenient method for decoding your data before it enters the input, without needing a separate filter in your Logstash pipeline.
enable_metric
edit- Value type is boolean
-
Default value is
true
Disable or enable metric logging for this specific plugin instance by default we record all the metrics we can, but you can disable metrics collection for a specific plugin.
id
edit- Value type is string
- There is no default value for this setting.
Add a unique ID
to the plugin configuration. If no ID is specified, Logstash will generate one.
It is strongly recommended to set this ID in your configuration. This is particularly useful
when you have two or more plugins of the same type, for example, if you have 2 exec inputs.
Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.
input { exec { id => "my_plugin_id" } }
tags
edit- Value type is array
- There is no default value for this setting.
Add any number of arbitrary tags to your event.
This can help with processing later.
type
edit- Value type is string
- There is no default value for this setting.
Add a type
field to all events handled by this input.
Types are used mainly for filter activation.
The type is stored as part of the event itself, so you can also use the type to search for it in Kibana.
If you try to set a type on an event that already has one (for example when you send an event from a shipper to an indexer) then a new input will not override the existing type. A type set at the shipper stays with that event for its life even when sent to another Logstash server.