Chainlink VMT Adapter

This repository contains an external adapter that performs computations for Verifiable Merkle Trees. In the alpha release of VMTree, the external adapter's Docker container sits alongside the Chainlink and Postgres containers on a given host.

Architecture

Structure

Adapter logic callable by the chainlink node is contained in endpoints. The app.js file imports and exposes adapter logic at an endpoint matching its name using camelCase capitalization, however it is still a module. The actual server is started in index.js. We can specify a custom port by setting the VMT_ADAPTER_PORT environment variable in .env, or else it will use the default port 8080. Note that if you alter the adapter port, then the docker-compose file needs to be modified as well.

Install

This adapter runs in docker. We use docker to take advantage of networking with the chainlink node, because we use this adapter on the same machine as our chainlink node that is also running in a docker container.

1. Clone the repository.

$ git clone https://github.com/vmtree/adapter.git
$ cd adapter

2. Download the zero knowledge proving/verifying keys and the wasm circuits for generating proofs. Run the shell script in scripts. You may have to alter the permissions of the file to get it to run on your machine.

$ ./scripts/get_zk_keys.sh

The above command will populate /src/zk-stuff with the necessary files for generating and verifying zero knowledge proofs for VMTrees:

# expected contents of zk-stuff after running script
.gitignore
massUpdateVerifier.json
massUpdate.wasm
massUpdate.zkey
updateVerifier.json
update.wasm
update.zkey

If you don't download these files, then the adapter will not work.

3. Build the image.

$ docker-compose build

Run

$ docker-compose up -d

Verify the container is up with

$ docker ps -a 

Testing locally

You can test locally without using docker. Follow steps 1-2 from above to install the code and the zk keys.

1. Install the app locally using yarn/npm.

$ yarn

or

$ npm install

2. Start the development server.

$ npx nodemon

3. Now, in a second terminal window or tab, send a request to either endpoint.

$ node test/testVmtUpdate.t.js

$ node test/testVmtMassUpdate.t.js