Golem pipelines is a library that allows to spawn golem tasks in declarative form, this approach unlocks some sexy features.

• declarative Declarative code should be easier to read/maintain/extend particularly for projects requiring high levels of parallel computation across distributed systems.
• composability Cause of pipeline/stage/executable abstraction it is easy to build reusable tasks. This could be intresting direction of development especially in web.
• pipelining It means that task_3 will start as soon as task_0 finishes. We don't have to wait for task_1. The dependency is defined by output <> input variables between two or more tasks. (stages are run concurrently)
• checkpoints Every task result after successful execution is persisted. Thus we don't loose progress on interrupted pipelines. It also allows for iterative building new stages, without re-running already working stages over and over again. code
  • FsCheckPointer - persists checkpoints to file system
  • S3CheckPointer - (TBD) interface can be easily implemented for S3 which would be good solution for browser execution
• Input Input abstraction allows to choose from different input resources code
  • FileInput - upload files to Provider, and pass path as args to command line
  • ArgInput - command line arguments
  • S3Input - (TBD) interface can be easily implemented for S3 which would be good solution for browser execution
• Executable Different modes of execution tasks, reduce boilerplate code. Handle executing binaries. code
  • ExecutableToStdout - executes program and treats stdout as a result
  • ExecutableToFiles- allows producing multiple results (files) from single input

• visualization - Such organized pipelines could be easily visualized using graphs. Also info about bills should be displated. Could be visualized in real time, by implementing event bus. I didn't make it in time :(
• s3 interfaces - I didn't make it in time :(

• Really great experience. Most of the things were working out of the box. Interface (js-sdk) is very intuitive. Generally it was pleasure to this library. Good job!
• What could be better
  • I would love to see more stream API exposed both for uploading data to provider and for fetching. It would avoid copying data, and allow processing bigger files. (I had problem with ctx.spawn api I didnt managed to make it work)
  • I was getting error when tried to upload/download file concurrently - I lost the error but it was something like Bus State Busy

Checkout out example of using this library: example