Documentation

8.12. Execute external script or program¶

The external-executable event handler can be configured to call an external script or program based on an event.

8.12.1. Introduction ¶

This event handler will call an external script or executable. At the end of the execution it will emit the event 20053 with the following details:

command - the actual command that was called
exit_code` - the exit code
output - full standard output generated while calling the executable or script.
error - full standard error generated while calling the executable or script.
output_log - the first 200 characters from the standard output, sanitized to be included in logs.
error_log - the first 200 characters from the standard error, sanitized to be included in logs.

The following environment variables are available to the executed script or program:

EVENT:: ID of the event for which it was called.
HANDLER_UUID:: UUID of this event handler.
COMPONENT_UUID:: UUID of the SFTPPlus component which has created the event.
TIMESTAMP:: Unix timestamp when this event was generated.
PEER:: Associated IP and PORT
USER:: Associated user/account.
DATA_*:: Data members of this event. For example DATA_REAL_PATH or DATA_DETAILS.

The following environment variables are copied from the main SFTPPlus process:

PATH
PWD - Linux and macOS only
SystemDrive - Windows only
SystemRoot - Windows only

SFTPPlus will only call a maximum of 3 external commands in parallel. External commands that need to be triggered for the generated events are queued and executed one after another. This is done to prevent extreme usage of the OS resources.

Since you can receive 1000 files in a short period, launching 1000 operating system sub-processes at the same time can result in blocking the whole operating system by using too much memory or too many processes. For example, with an external executable using 100MB of memory, calling 10 concurrent such jobs would result in 1GB of extra memory usage.

The external-executable event handler is designed to be used as a notification mechanism or for calling external commands that are fast and have low-memory usage. The event handler is not designed to operate as a sub-process manager, nor for the handling of long-running or extensive memory usage processes.

If your external executable uses more than 100MB of memory or takes longer than 10 seconds to operate, consider redesigning your system. For example reduce the run duration or reduce the run frequency by filtering events with the target and data_filter options).

8.12.2. name ¶

Default value:

Optional:

From version:

2.10.0

Values:

Any text.

Description:

Human-readable short text used to identify this event handler.

8.12.3. description ¶

Default value:

Optional:

Yes

From version:

2.10.0

Values:

Any text.

Description:

Human-readable text that describes the purpose of this event handler.

8.12.4. type ¶

Default value:

Optional:

From version:

2.10.0

Values:

file-dispatcher - Dispatch a file into one or multiple paths.
http - HTTP POST request (unsecured).
local-file - Append events to a file located on the local file system.
email-sender - Send emails as an SMTP client.
windows-eventlog - Send events to Windows EventLog Service.
standard-stream - Send events to standard output.
syslog - Local Unix socket or remote IP:PORT address for Syslog.
create-archive - Create/Compresses one or more files.
extract-archive - Extract/Uncompressed a file.
external-executable - Execute an external script or program.
openpgp - Encrypt/Decrypt files using OpenPGP.
rabbitmq - Publish event to RabbitMQ AMQP 0-9-1 server.
extension - For custom event handlers implemented using our API.

Description:

This option specifies the type of the event handler. Each type has a set of specific configuration options.

8.12.5. target ¶

Default value:

Optional:

Yes

Values:

Comma separated list of event ids.
Comma separated list of event ids starting with an exclamation mark.
Leave empty to handle all events.

From version:

2.10.0

Description:

Define a comma separated list of event ids to have the event handler triggered only for those events.

When you want to have it triggered for all the events, excepting a few events you should prefix each event id with the exclamation mark (!).

Leave it empty to handle all events.

Note

Combining the two methods is not supported as the same result can be achieved by allowing only the desired events, all the others will be ignored.

8.12.6. groups ¶

Default value:

Optional:

Yes

Values:

Comma separated list of event groups.
Comma separated list of event groups starting with an exclamation mark.
Empty.

From version:

3.39.0

Description:

Defines the list of event groups for which this handler is active.

When you want to handle all the events, except for the ones from a set of groups, prefix the group names with the exclamation mark (!).

An event can be a member of one or multiple groups. The event is handled if any of its groups is found in the list of configured allowed groups. The event is not handled if any of its groups is found in the list of configured ignored groups (starting with !).

Leave it empty to handle events from all groups.

8.12.7. usernames ¶

Default value:

Optional:

Yes

Values:

Comma separated list of usernames.
Comma separated list of usernames starting with an exclamation mark.
Leave empty to handle all events.

From version:

3.9.0

Description:

Comma separated list of usernames whose events are handled by this event handler. A username can include OS accounts, application accounts, and any accounts accepted by any authentication method including external HTTP accounts.

When you want to have it triggered for all the events, excepting a few events you should prefix each username with the exclamation mark (!).

Leave it empty to handle events from any users or events which are not associated with any user.

8.12.8. components ¶

Default value:

Optional:

Yes

Values:

Comma separated list of UUIDs.
Comma separated list of UUIDs starting with an exclamation mark.
Leave empty to handle all events.

From version:

3.18.0

Description:

Comma separated list of component UUIDs for which events are handled by this event handler.

When you want to have it triggered for all the events, excepting a few events you should prefix each UUID with the exclamation mark (!).

Leave it empty to handle events emitted by any component.

8.12.9. source_addresses ¶

Default value:

Empty

Optional:

Yes

Values:

Comma separated list of IP addresses.
List of IP addresses starting with an exclamation mark.
Empty.

From version:

3.40.0

Description:

Comma separated list of source IP addresses of the remote peers, which are handled by this event handler.

When you want to have it triggered for all the addresses, excepting a few addresses you should prefix each address with the exclamation mark (!).

Leave it empty to handle events emitted by any source address.

8.12.10. data_filter ¶

Default value:

Optional:

Yes

Values:

Comma-separated list of data member names and filter expressions.
Multiple expressions, one per line (Since 4.29.0)
Leave empty to handle all events.

From version:

3.22.0

Description:

Comma separated definition with the name of attribute data member and the targeted matching expression.

Data member names are configured with insensitive cases.

For more details about the available expressions see the matching expression documentation.

The following example will extract the value to be matched/filtered from the path data member of the event. The extracted value is then matched against the */folderA/* globbing expression:

[event-handlers/b904ed23-a234-4ccf-8abd-edcae4d3324f]
data_filter = path, */folderA/*

See the usage instructions for more operational details.

You can filter based on multiple data members using multiple rules. Each rule is defined on a separate line.

In the following example, events are triggered only if they are uploaded into the directory named reports-A with a size of 0 bytes (empty file):

[event-handlers/b904ed23-a234-4ccf-8abd-edcae4d3324f]
data_filter =
    path, */reports-A/*
    size, 0

Leave this configuration empty to not filter based on the event's attached data, and handle events regardless of their data attributes.

8.12.11. fail_after_errors ¶

Default value:

Optional:

Yes

From version:

3.0.0

Values:

An integer number greater than 0.
0 Disabled.

Description:

Number of consecutive errors after which the event handler will automatically stop with a failed state.

Setting this to 0 will disable the feature. The event handler will no longer stop regardless of the number of errors encountered.

8.12.12. executable_path ¶

Default value:

Optional:

Values:

Local filesystem path.

From version:

3.47.0

Description:

Local filesystem path to the executable.

8.12.13. executable_arguments ¶

Default value:

{data.real_path}

Optional:

Yes

Values:

Plain text.
Variable expression.

From version:

3.47.0

Description:

This configuration defines the arguments used to call the executable.

Make sure the arguments that might contain spaces are enclosed in quotes.

The following variables (case-insensitive) are provided as context data containing information about the event being triggered:

id
uuid
message
account.name
account.email
account.peer.address
account.peer.port
account.peer.protocol
account.peer.family
account.uuid
component.name
component.type
component.uuid
timestamp.cwa_14051
timestamp.iso_8601
timestamp.iso_8601_fractional
timestamp.iso_8601_local
timestamp.iso_8601_basic
timestamp.iso_8601_compact
timestamp.timestamp
server.name
server.uuid
data.DATA_MEMBER_NAME
data_json

8.12.14. executable_output_format ¶

Default value:

text

Optional:

Yes

Values:

text
json

From version:

4.32.0

Description:

This configuration defines the expected output generated by this command.

Default option is text and the output will be handled without any additional processing. The standard output value generated by the call will be available inside the event as data.output.

When this is configured as json the output is expected to be a valid JSON object. The JSON object will be available inside the event at data.output.

For example, parts of the following JSON object can be accesses as data.output.member2.other:

{"member1": "value1", "member2": {"other": "object", "not": "supported"}

8.12.15. executable_timeout ¶

Default value:

Optional:

Yes

Values:

Number

From version:

3.47.0

Description:

Number of seconds to allow for the external process to execute before forcefully closing it.

A configured value must be equal to or greater than 1.

8.12.16. concurrent_processes ¶

Default value:

Optional:

Yes

Values:

Number

From version:

3.47.0

Description:

The maximum number of concurrent processes to execute at the same time.

When the event handler is required to handle more events, the remaining events are placed in the queue and executed as soon as possible, making sure that only the configured number or processes are active at the same time.

A configured value must be equal to or greater than 1.

We recommend setting this based on the number of available CPUs.

8.11. Extract archive / uncompress

8.13. Encrypt / decrypt using OpenPGP / GPG