raji-narayanan / stream

Elegant stream processing pipeline written entirely in Golang

Streams is a pipeline based, stream processing action for the Project Flogo Ecosystem

Flogo Stream

Edge devices have the potential for producing millions or even billions of events at rapid intervals, often times the events on their own are meaningless, hence the need to provide basic streaming operations against the slew of events.

A native streaming action as part of the Project Flogo Ecosystem accomplishes the following primary objectives:

• Enables apps to implement basic streaming constructs in a simple pipeline fashion
• Provides non-persistent state for streaming operations
  • Streams are persisted in memory until the end of the pipeline
• Serves as a pre-process pipeline for raw data to perform basic mathematical and logical operations. Ideal for feeding ML models

Some of the key highlights include:

😀 Simple pipeline construct enables a clean, easy way of dealing with streams of data
⏳ Stream aggregation across streams using time or event tumbling & sliding windows
🙌 Join streams from multiple event sources
🌪 Filter out the noise with stream filtering capabilities

Getting Started

We’ve made building powerful streaming pipelines as easy as possible. Develop your pipelines using:

• A simple, clean JSON-based DSL
• Golang API

See the sample below of an aggregation pipeline (for brevity, the triggers and metadata of the resource has been omitted). Also don’t forget to check out the examples in the project-flogo/stream repo.

  "stages": [
    {
      "ref": "github.com/TIBCOSoftware/flogo-contrib/activity/aggregate",
      "settings": {
        "function": "sum",
        "windowType": "timeTumbling",
        "windowSize": "5000"
      },
      "input": {
        "value": "=$.input"
      }
    },
    {
      "ref": "github.com/TIBCOSoftware/flogo-contrib/activity/log",
      "input": {
        "message": "=$.result"
      }
    }
  ]

Try out the example

Firstly clone the repository

Create a skeletal Flogo Application, we'll call it StreamAggregatorApp

$ flogo create -flv github.com/TIBCOSoftware/flogo-contrib/activity/log@master,github.com/TIBCOSoftware/flogo-lib/app/resource@master StreamAggregatorApp

Creating initial project structure, this might take a few seconds ...
Warning: Gopkg.lock is out of sync with Gopkg.toml or the project's imports.
Fetching sources...

The following packages are not imported by your project, and have been temporarily added to Gopkg.lock and vendor/:
	github.com/TIBCOSoftware/flogo-contrib/activity/log
	github.com/TIBCOSoftware/flogo-lib/app/resource
If you run "dep ensure" again before actually importing them, they will disappear from Gopkg.lock and vendor/.

Now, install dependencies...

$ cd StreamAggregatorApp/
$ flogo install github.com/TIBCOSoftware/flogo-lib/app/resource
$ flogo install github.com/TIBCOSoftware/flogo-contrib/activity/aggregate

Overwrite the generated flogo.json with the example...

$ cp ../agg-flogo.json ./flogo.json

Fixup the flogo.json so that the name attribute is correct for the Application name we've chosen i.e replace "stream" with "StreamAggregatorApp"

$ vi flogo.json # — Change name to “StreamAggregatorApp”

Now, install the Flogo Stream dependencies and then ensure everything in src is upto date with a 'flogo ensure'

flogo install github.com/project-flogo/stream
flogo ensure -update

Build it...

flogo build