Dummy Chain

This dummy "blockchain" serves as a demonstration on how to instrument node for the Firehose integration. Instrumentors, "firehose" is a part responsible for data extraction and could be turned on with an environment variable when running the chain process.

Requirements

• Go

Getting Started

To install the binary:

go install github.com/streamingfast/dummy-blockchain@latest

Note

Ensure go env GOPATH directoy is part of your PATH (export PATH="`go env GOPATH`:$PATH")

To start the chain, run:

./dummy-blockchain start

You'll start seeing output like:

INFO[2022-01-13T11:55:07-06:00] initializing node
INFO[2022-01-13T11:55:07-06:00] initializing store
INFO[2022-01-13T11:55:07-06:00] initializing engine
INFO[2022-01-13T11:55:07-06:00] starting block producer                       rate=1s
INFO[2022-01-13T11:55:08-06:00] processing block                              hash=6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b height=1
INFO[2022-01-13T11:55:09-06:00] processing block                              hash=d4735e3a265e16eee03f59718b9b5d03019c07d8b6c51f90da3a666eec13ab35 height=2
INFO[2022-01-13T11:55:10-06:00] processing block                              hash=4e07408562bedb8b60ce05c1decfe3ad16b72230967de01f640b7e4729b49fce height=3
INFO[2022-01-13T11:55:11-06:00] processing block                              hash=4b227777d4dd1fc61c6f884f48641d02b4d121d3fd328cb08b5531fcacdabf8a height=4
INFO[2022-01-13T11:55:12-06:00] processing block                              hash=ef2d127de37b942baad06145e54b0c619a1f22327b2ebbcfbec78f5564afe39d height=5
INFO[2022-01-13T11:55:13-06:00] processing block                              hash=e7f6c011776e8db7cd330b54174fd76f7d0216b612387a5ffcfb81e6f0919683 height=6

To enable firehose instrumentation:

./dummy-blockchain start --tracer=firehose

Firehose logger statement will be printed as blocks are executed/produced. This mode is meant to be run using by a Firehose reader-node, see https://github.com/streamingfast/firehose-acme.

Block Skipping and Forks

The dummy chain skips a block that are divisible by 13 so for example we are at block #25 (abc) the next produced block will be #27 (def) and #26 will never be produced.

THe dummy chain also generates forks at regular interval, every 17 blocks. The generated fork sequence is of 1 block if the current block is odd otherwise if it's even, a 2 blocks fork sequence will be generated.

Tracer

This project showcase a "fake" blockchain's node codebase. For developers looking into integrating a native Firehose integration, we suggest to integrate in blockchain's client code directly by some form of tracing plugin that is able to receive all the important callback's while transactions are execution integrating as deeply as wanted.

You will see here in tracer/tracer.go and tracer/firehose_tracer.go a sketch of such "plugin" in Golang, geth can be inspected to see a full fledged block synchronization tracing plugin in a production codebase.

The output format must strictly respect https://github.com/streamingfast/firehose-core standard, the tracer/firehose_tracer.go implementation shows how we suggest implementing such tracer, you are free to implement the way you like.

Building

Clone the repository:

git clone https://github.com/streamingfast/dummy-blockchain.git
cd dummy-blockchain

go run . start

HTTP API

Dummy chain comes equipped with a simple HTTP API to check on status and blocks.

API server starts on 0.0.0.0:8080 by default.

List of available endpoints:

• / - Readme page
• /status - Get chain status
• /block - Get block for latest height
• /blocks/:height - Get block for a specific height

Contributors

• Figment: Initial Implementation

License

Apache 2.0