Conduit Processor SDK

This repository contains the Go software development kit for implementing a processor for Conduit.

Note: if you'd like to use another language for writing processors, feel free to open an issue and request a processor SDK for a specific language.

Quick Start

Create a new folder and initialize a fresh go module:

go mod init example.com/conduit-processor-example

Add the processor SDK dependency:

go get github.com/conduitio/conduit-processor-sdk

You can now create a new processor by implementing the Processor interface. For more details about that, check our documentation for Building Standalone Processors.

On the other hand, if the processor is very simple and can be reduced to a single function (e.g. no configuration needed), then we can use sdk.NewProcessorFunc(), as below:

//go:build wasm

package main

import (
    sdk "github.com/conduitio/conduit-processor-sdk"
)

func main() {
    sdk.Run(sdk.NewProcessorFunc(
        sdk.Specification{Name: "example-processor"},
        func(ctx context.Context, rec opencdc.Record) (opencdc.Record, error) {
            // do something with the record
            return rec, nil
        },
    ))
}

With this, you are set to build your processor. Note that we are building the processor as a WebAssembly module, so you need to set GOARCH and GOOS:

GOARCH=wasm GOOS=wasip1 go build -o example-processor.wasm main.go

The produced example-processor.wasm file can be used as a processor in Conduit. Copy it to the processors directory of your Conduit instance and configure it in the processors section of the pipeline configuration file.

FAQ

Why do I need to specify GOARCH and GOOS?

Conduit uses WebAssembly to run standalone processors. This means that you need to build your processor as a WebAssembly module. You can do this by setting the environment variables GOARCH=wasm and GOOS=wasip1 when running go build. This will produce a WebAssembly module that can be used as a processor in Conduit.

How do I use a processor?

To use a standalone WASM processor in Conduit, the following two steps need to be done:

1. Copying the WebAssembly module to the processors directory of your Conduit instance. By default, that's a directory called processors that is in the same directory as Conduit. The directory can be changed with the -processors.path flag.

   An example directory structure would be:

   .
   ├── conduit
   └── processors
       └── example-processor.wasm
   

2. Use the processor in the processors section of the pipeline configuration file. using the name the processor defines in its specifications. For example:

   processors:
     - id: my-example-processor
       plugin: example-processor
       settings:
         field: 'foo'
         value: 'bar'
   

How do I log in a processor?

You can get a zerolog.Logger instance from the context using the sdk.Logger function. This logger is pre-configured to append logs in the format expected by Conduit.

Keep in mind that logging in the hot path (i.e. in the Process method) can have a significant impact on the performance of your processor, therefore we recommend to use the Trace level for logs that are not essential for the operation of the processor.

Example:

func (p *ExampleProcessor) Process(ctx context.Context, records []opencdc.Record) []sdk.ProcessedRecord {
    logger := sdk.Logger(ctx)
    logger.Trace().Msg("Processing records")
    // ...
}