Source FTP

Purpose

Defines the specific bucket and folder source of a FTP connected endpoint.

This Asset can be used by:

Asset type	Link
Input Processors	Stream Input Processor

Prerequisite

You need:

• FTP Connection

Configuration

Name & Description

Name : Name of the Asset. Spaces are not allowed in the name.

Description : Enter a description.

The Asset Usage box shows how many times this Asset is used and which parts are referencing it. Click to expand and then click to follow, if any.

Required roles

In case you are deploying to a Cluster which is running (a) Reactive Engine Nodes which have (b) specific Roles configured, then you can restrict use of this Asset to those Nodes with matching roles. If you want this restriction, then enter the names of the Required Roles here. Otherwise, leave empty to match all Nodes (no restriction).

Throttling & Failure Handling

Throttling

The following parameters allow to control the maximum number of new stream creations per given time period.

• Max. new streams: Maximum number of streams this source is supposed to open resp. process within a given time period.
• Per: Time interval unit for the provided Max. new streams number from the drop-down list.

info

Configuration values for this parameter are dependent on the use case scenario. Assuming your data arrives in low frequency cycles these values are negligible. In scenarios with many objects arriving in short time frames it is recommended to have a closer look on adapting the default values.

Backoff Failure Handling

These parameters define the backoff timing intervals in case of failures. Based on the following parameters, the system will step by step throttle down the processing cycle based on the time boundaries of min. failure backoff and max. failure backoff. It thereby allows to slow down the processing during failure scenarios.

• Min. failure backoff: The minimum backoff time before the next source item processing (in case of failure scenario).
• Unit: The Unit that goes with the given minimum time value.
• Max. failure backoff: The maximum backoff time before the next source item processing (in case of failure scenario).
• Unit: The Unit that goes with the given maximum time value.

Based on these values the next processing will be delayed: starting with the min. failure backoff time interval the waiting time will be increased step by step up to the max. failure backoff.

• Reset after number of successful streams: The backoff failure throttling reset.
• Reset after time without failure streams: Time-based reset for backoff failure throttling .
• Unit: The Unit that goes with the given time-based backoff failure throttling reset.

Whatever comes first will reset the failure scenario throttling after the system is back to successful stream processing.

Polling & Processing

This source does not reflect a stream, but an object based storage source which does not signal the existence of new objects to observers. We therefore need to define how often we want to look-up (poll) the source for new objects to process.

You can choose between Fixed rate polling and Cron tab style polling:

Fixed rate

Use Fixed rate if you want to poll in constant and frequent intervals.

• Polling interval [sec]: Enter the interval in seconds in which the configured source should be queried for new objects.

Cron tab

Use Cron tab if you want to poll at determined times. The Cron tab expression follows the cron tab style convention which may be familiar to you. In all other cases you can read more about crontab and the syntax here. You can simulate cron settings using this smart website. Or you can use the Cron expression editor provided underneath the calendar symbol on the right hand side:

Configure your expression with the help of this editor. The Next trigger times at the top helps to visualize the configured expression. Press OK towards the end of this editor window to store the given values.

Polling timeout

The Polling timeout [sec] defines the time in seconds to wait until a polling request fails. Depending on the endpoint and its responsiveness you may want to change this number to something higher or lower. You should set it high enough, so that you are confident that the endpoint responds under normal operation.

Stable time

The Stable time [sec] defines the number of seconds that file statistics must stay unchanged for considering it as stable. Configuring a value in here will check the appropriate file stability before processing the file.

Ordering

When listing objects from the source for processing, you can define in what order they should be processed. Pick one of the following self-explanatory settings:

• Alphabetically, ascending
• Alphabetically, descending
• Last modified, ascending
• Last modified, descending

Reprocessing mode

Configuring the Reprocessing mode relates to layline.io's Access Coordinator feature. You can pick between three modes:

• Manual access coordinator reset: any source element processed and stored in layline.io's history needs manual reset within the Sources Coordinator before reprocessing of a re-ingested source is performed (default mode).
• Automatic access coordinator reset: this mode allows the automatc reprocessig of already processed and re-ingested sources as soon as the respective input source has been moved into the configured done or error directory.
• When input changed: this mode behaves as described in Manual access coordinator reset while it performs an additional check whether the source has potentially changed; i.e. the name of the source is identical but the content differs. In case the input in fact changed, the reprocessing will start without manual intervention.

Wait for processing clearance

Activating this checkbox identifies new input sources as Wait for processing clearance. This means, the input source leaves unprocessed in the input directory until a) a manual intervention through Operations provides active clearance for processing the respective file or b) some Javascript executes the AccessCoordinator.giveClearance(source: string, stream: string, timeout?: number) method.

FTP Connection

Select the previously configured FTP Connection to use for this Source.

Folders

This source requires the definition of Folders.

Use + ADD A FOLDER for entering the configuration details.

• Folder setup name : Name of the Folder. Spaces are not allowed in the name.
• Folder setup description : Enter a description.

One Folder basically consists of the definition of three different directories:

1. Input Directory : The directory to read new files from.
2. Done Directory : The directory to which read files are moved after reading.
3. Error Directory : Files which caused problems during processing are moved to the Error Directory for further analysis.

In case the Source is supposed to collect data from more than one Folder structure, it is possible to add multiple Folder configurations.

Input Directory

• Input Directory : The directory to read files from. The path of the directory must be accessible to the Reactive Engine trying to access this Source. You can use ${...} macros to expand variables defined in environment variables.

• Filter regular expression : Regular expression to filter which files in the directory are pulled.

• File prefix regular expression : A regular expression filter which is applied to the beginning of a file name. E.g. XYZ. will lead to only those files read which filename starts with XYZ followed by anything.

• File suffix regular expression : A regular expression filter which is applied to the end of a file name. E.g. .zip will lead to only those files read which filename ends with zip preceded by anything.

• Include sub-directories : Scan sub-directories to the input directory also.

• Enable housekeeping : Allows to apply housekeeping rules for files within the input directory. You can configure your required options.

  

Done Directory

• Done Directory : The directory to which files are moved when fully processed. The path of the directory must be accessible to the Reactive Engine trying to access this Source. You can use ${...} macros to expand variables defined in environment variables.

• Done prefix : Prefix to add to the filename of the processed file after move to the done directory. E.g. done_ will add the done_-prefix to the beginning of the filename when moved to the done directory.

• Done suffix : Suffix to add to the filename of the processed file after move to the done directory. E.g. _done will add the _done-suffix to the end of the filename when moved to the done directory.

• "File already exists"-Handling : Define your required handling in case the file already exists in the done-directory.

  

• Enable housekeeping : Allows to apply housekeeping rules for files within the done directory. You can configure your required options.

  

Error Directory

• Error Directory : The directory to which files are moved in case of a problem with the file during processing. The path of the directory must be accessible to the Reactive Engine trying to access this Source. You can use ${...} macros to expand variables defined in environment variables.

• Error prefix : Prefix to add to the filename of the processed file after move to the error directory. E.g. error_ will add the error_-prefix to the beginning of the filename when moved to the error directory.

• Error suffix : Suffix to add to the filename of the processed file after move to the error directory. E.g. _error will add the _error-suffix to the end of the filename when moved to the error directory.

• "File already exists"-Handling : Define your required handling in case the file already exists in the error-directory.

  

• Enable housekeeping : Allows to apply housekeeping rules for files within the error directory. You can configure your required options.

  

Related Topics

Internal

• FTP Connection
• FTP Sink

External

• Cron on Wikipedia
• Cron editor online from crontab guru

Potential problems

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Can't find what you are looking for?

Please note, that the creation of the online documentation is Work-In-Progress. It is constantly being updated. should you have questions or suggestions, please don't hesitate to contact us at support@layline.io .