graph-autopipe

Example of user-configurable pipeline

This example demonstrates how to user the high-level API.

The main function in the autopipe.go file does the following:

• Registers three types of pipeline stages:

  • HttpIngest, which listens for HTTP POST connections and forwards them as a byte array.
  • FieldDeleter, which receives a map, deletes the fields specified in the configuration, and forwards it to the next stage of the pipeline.
  • StdoutExport, which receives strings and prints them in the standard output.

• Registers codecs that will automatically wire different types of stages, in case they have incompatible stages. For example, if you wire the output of the HttpIngest to the StdoutExport stage, you need a codec that transforms byte arrays to strings; if you wire the output of the HttpIngest to the FieldDeleter stage, you need a codec that transforms JSON byte arrays to maps.

• Reads the config that instantiates the different stages of the pipeline and connects them. The Graph Builder will automatically add the codecs in the different stages, if they have incompatible input/output types.

You can get a look to the nodes.hcl example configuration file, where an HTTP server forwards its output to two stages: a FieldDeleter that removes any field named "password" and "secret", and a StdoutExport that just prints the received messages. At the same time, the FieldDeleter forwards the "safe" maps to another StdoutExport.

You can run the example with:

go run autopipe.go -graph nodes.hcl

In another terminal, you can submit an example JSON:

curl -X POST -d '{"hello":"my friend","password":"sup3rs3cr37","secret":"kadlfjjsdlaf"}' http://localhost:8080

In the program standard output, you will see:

Received message: {"hello":"my friend","password":"sup3rs3cr37","secret":"kadlfjjsdlaf"}
Safe-to-show message: {"hello":"my friend"}

You can give a try modifying the parameters and connections of the nodes.hcl file, even instantiating new stages or removing them.