sftpgo/docs/custom-actions.md

Custom Actions

SFTPGo can notify filesystem and provider events using custom actions. A custom action can be an external program or an HTTP URL.

Filesystem events

The actions struct inside the common configuration section allows to configure the actions for file operations and SSH commands. The hook can be defined as the absolute path of your program or an HTTP URL.

The following actions are supported:

• download
• pre-download
• upload
• pre-upload
• delete
• pre-delete
• rename
• mkdir
• rmdir
• ssh_cmd

The upload condition includes both uploads to new files and overwrite of existing ones. If an upload is aborted for quota limits SFTPGo tries to remove the partial file, so if the notification reports a zero size file and a quota exceeded error the file has been deleted. The ssh_cmd condition will be triggered after a command is successfully executed via SSH. scp will trigger the download and upload conditions and not ssh_cmd. For cloud backends directories are virtual, they are created implicitly when you upload a file and are implicitly removed when the last file within a directory is removed. The mkdir and rmdir notifications are sent only when a directory is explicitly created or removed.

The notification will indicate if an error is detected and so, for example, a partial file is uploaded.

The pre-delete action, if defined, will be called just before files deletion. If the external command completes with a zero exit status or the HTTP notification response code is 200 then SFTPGo will assume that the file was already deleted/moved and so it will not try to remove the file and it will not execute the hook defined for the delete action.

The pre-download and pre-upload actions, will be called before downloads and uploads. If the external command completes with a zero exit status or the HTTP notification response code is 200 then SFTPGo allows the operation, otherwise the client will get a permission denied error.

If the hook defines a path to an external program, then this program can read the following environment variables:

• SFTPGO_ACTION, supported action
• SFTPGO_ACTION_USERNAME
• SFTPGO_ACTION_PATH, is the full filesystem path, can be empty for some ssh commands
• SFTPGO_ACTION_TARGET, full filesystem path, non-empty for rename SFTPGO_ACTION and for some SSH commands
• SFTPGO_ACTION_VIRTUAL_PATH, virtual path, seen by SFTPGo users
• SFTPGO_ACTION_VIRTUAL_TARGET, virtual target path, seen by SFTPGo users
• SFTPGO_ACTION_SSH_CMD, non-empty for ssh_cmd SFTPGO_ACTION
• SFTPGO_ACTION_FILE_SIZE, non-zero for pre-upload,upload, download and delete actions if the file size is greater than 0
• SFTPGO_ACTION_FS_PROVIDER, 0 for local filesystem, 1 for S3 backend, 2 for Google Cloud Storage (GCS) backend, 3 for Azure Blob Storage backend, 4 for local encrypted backend, 5 for SFTP backend
• SFTPGO_ACTION_BUCKET, non-empty for S3, GCS and Azure backends
• SFTPGO_ACTION_ENDPOINT, non-empty for S3, SFTP and Azure backend if configured
• SFTPGO_ACTION_STATUS, integer. Status for upload, download and ssh_cmd actions. 1 means no error, 2 means a generic error occurred, 3 means quota exceeded error
• SFTPGO_ACTION_PROTOCOL, string. Possible values are SSH, SFTP, SCP, FTP, DAV, HTTP, HTTPShare, OIDC, DataRetention, EventAction
• SFTPGO_ACTION_IP, the action was executed from this IP address
• SFTPGO_ACTION_SESSION_ID, string. Unique protocol session identifier. For stateless protocols such as HTTP the session id will change for each request
• SFTPGO_ACTION_OPEN_FLAGS, integer. File open flags, can be non-zero for pre-upload action. If SFTPGO_ACTION_FILE_SIZE is greater than zero and SFTPGO_ACTION_OPEN_FLAGS&512 == 0 the target file will not be truncated
• SFTPGO_ACTION_TIMESTAMP, int64. Event timestamp as nanoseconds since epoch

Previous global environment variables aren't cleared when the script is called. The program must finish within 30 seconds.

If the hook defines an HTTP URL then this URL will be invoked as HTTP POST. The request body will contain a JSON serialized struct with the following fields:

• action, string
• username, string
• path, string
• target_path, string, included for rename action and sftpgo-copy SSH command
• virtual_path, string, virtual path, seen by SFTPGo users
• virtual_target_path, string, virtual target path, seen by SFTPGo users
• ssh_cmd, string, included for ssh_cmd action
• file_size, int64, included for pre-upload, upload, download, delete actions if the file size is greater than 0
• fs_provider, integer, 0 for local filesystem, 1 for S3 backend, 2 for Google Cloud Storage (GCS) backend, 3 for Azure Blob Storage backend, 4 for local encrypted backend, 5 for SFTP backend, 6 for HTTPFs backend
• bucket, string, included for S3, GCS and Azure backends
• endpoint, string, included for S3, SFTP and Azure backend if configured
• status, integer. Status for upload, download and ssh_cmd actions. 1 means no error, 2 means a generic error occurred, 3 means quota exceeded error
• protocol, string. Possible values are SSH, SFTP, SCP, FTP, DAV, HTTP, HTTPShare, OIDC, DataRetention, EventAction
• ip, string. The action was executed from this IP address
• session_id, string. Unique protocol session identifier. For stateless protocols such as HTTP the session id will change for each request
• open_flags, integer. File open flags, can be non-zero for pre-upload action. If file_size is greater than zero and file_size&512 == 0 the target file will not be truncated
• timestamp, int64. Event timestamp as nanoseconds since epoch

The HTTP hook will use the global configuration for HTTP clients and will respect the retry configurations.

The pre-* actions are always executed synchronously while the other ones are asynchronous. You can specify the actions to run synchronously via the execute_sync configuration key. Executing an action synchronously means that SFTPGo will not return a result code to the client (which is waiting for it) until your hook have completed its execution. If your hook takes a long time to complete this could cause a timeout on the client side, which wouldn't receive the server response in a timely manner and eventually drop the connection. If you add the upload action to the execute_sync configuration key, SFTPGo will try to delete the uploaded file and return an error to the client if the hook fails. A hook is considered failed if the external command completes with a non-zero exit status or the HTTP notification response code is other than 200 (or the HTTP endpoint cannot be reached or times out). After a hook failure, the uploaded size is removed from the quota if SFTPGo is able to remove the file.

Provider events

The actions struct inside the data_provider configuration section allows you to configure actions on data provider objects add, update, delete.

The supported object types are:

• user
• folder
• group
• admin
• api_key
• share
• event_action
• event_rule

Actions will not be fired for internal updates, such as the last login or the user quota fields, or after external authentication.

If the hook defines a path to an external program, then this program can read the following environment variables:

• SFTPGO_PROVIDER_ACTION, supported values are add, update, delete
• SFTPGO_PROVIDER_OBJECT_TYPE, affected object type
• SFTPGO_PROVIDER_OBJECT_NAME, unique identifier for the affected object, for example username or key id
• SFTPGO_PROVIDER_USERNAME, the username that executed the action. There are two special usernames: __self__ identifies a user/admin that updates itself and __system__ identifies an action that does not have an explicit executor associated with it, for example users/admins can be added/updated by loading them from initial data
• SFTPGO_PROVIDER_IP, the action was executed from this IP address
• SFTPGO_PROVIDER_TIMESTAMP, event timestamp as nanoseconds since epoch
• SFTPGO_PROVIDER_OBJECT, object serialized as JSON with sensitive fields removed

Previous global environment variables aren't cleared when the script is called. The program must finish within 15 seconds.

If the hook defines an HTTP URL then this URL will be invoked as HTTP POST. The action, username, ip, object_type and object_name and timestamp are added to the query string, for example <hook>?action=update&username=admin&ip=127.0.0.1&object_type=user&object_name=user1&timestamp=1633860803249, and the full object is sent serialized as JSON inside the POST body with sensitive fields removed.

The HTTP hook will use the global configuration for HTTP clients and will respect the retry configurations.

The structure for SFTPGo objects can be found within the OpenAPI schema.

Pub/Sub services

You can forward SFTPGo events to several publish/subscribe systems using the sftpgo-plugin-pubsub. The notifiers SFTPGo plugins are not suitable for interactive actions such as pre-* events. Their scope is to simply forward events to external services. A custom hook is a better choice if you need to react to pre-* events.

Database services

You can store SFTPGo events in database systems using the sftpgo-plugin-eventstore and you can search the stored events using the sftpgo-plugin-eventsearch.