Envelope is a configuration-driven framework for Apache Spark that makes it easy to develop Spark-based data processing pipelines on a Cloudera EDH.

Envelope is simply a pre-made Spark application that implements many of the tasks commonly found in ETL pipelines. In many cases, Envelope allows large pipelines to be developed on Spark with no coding required. When custom code is needed, there are pluggable points in Envelope for core functionality to be extended. Envelope works in batch and streaming modes.

Some examples of what you can easily do with Envelope:

• Run a graph of Spark SQL queries, all in the memory of a single Spark job
• Stream in event data from Apache Kafka, join to reference data, and write to Apache Kudu
• Read in from an RDBMS table and write to Apache Parquet files on HDFS
• Automatically merge into slowly changing dimensions (Type 1 and 2, and bi-temporal)
• Insert custom DataFrame transformation logic for executing complex business rules

Envelope requires a CDH5.7+ cluster. Kafka 0.9 and Kudu 1.2 are required if connecting to those components.

You can build the Envelope application from the top-level directory of the source code by running the Maven command:

mvn clean package

This will create envelope-0.3.0.jar in the target directory.

Envelope provides four example pipelines that you can run for yourself:

• FIX: simulates receiving financial orders and executions and tracking the history of the orders over time.
  • This example includes a walkthrough that explains in detail how it meets the requirements.
• Traffic: simulates receiving traffic conditions and calculating an aggregate view of traffic congestion.
• Filesystem: demonstrates a batch job that reads a JSON file from HDFS and writes the data back to Avro files on HDFS.

You can run Envelope by submitting it to Spark with the configuration file for your pipeline:

spark-submit envelope-0.3.0.jar yourpipeline.conf

A helpful place to monitor your running pipeline is from the Spark UI for the job. You can find this via the YARN ResourceManager UI, which can be found in Cloudera Manager by navigating to the YARN service and then to the ResourceManager Web UI link.

If you are ready for more, dive in:

• User Guide - details on the design, operations, configuration, and usage of Envelope
• Configuration Guide - a deep-dive into the parameters and options of Envelope
• Planners Guide - directions and details on when, why, and how to use planners and associated outputs

Note that, like all Cloudera Labs projects, Envelope is not officially supported by Cloudera. For assistance with Envelope, please head over to the Cloudera Community forums and let us know your questions and feedback. If you wish to contribute to the project, we are happy to look at pull requests and issues on this Cloudera Labs repository.