@polkadot/client-db NPM

@polkadot/client

A JavaScript version of a Polkadot/Substrate network client. It allows operation in full and light nodes fullfilling all functions of chain operation, however does not include the ability to author blocks (i.e. run as a validator on the network).

Current status

This is the current status of the client -

It can sync and operate on Polkadot POC-3 networks, and has been tested against Alexander (Polkadot), Dried Danta (Substrate) as well as Edgeware networks.
It currently does not include much (if any) of the RPC interfaces - so it is not (currently) able to support eg. the apps UI connecting to it
It does not (currently) do any state and trie pruning, so the resulting backing database growth is not controlled
As of 0.19.1 the backing database has been swapped to LmDB, this interface is much faster than the previous implementation, however uses more disk space (follow-up from the previous point). Investigations are still ongoing as to the best fit for the backend DB engine.

Development overview

It is split up into a number of internal packages -

client The main JavaScript client
client-chains Chain definitions
client-db Database interface
client-p2p Peer-to-peer server
client-rpc RPC server
client-runtime Basic Wasm runtime wrapper
client-telemetry Substrate telemetry interface
client-types Specific codec types for client interfaces
client-wasm Wasm interface wrapper

Local development node

Start the node with yarn run start <options>, e.g. yarn run start --chain dried-danta. You can use --help to get a list of the available options.

Running via docker

A docker image is built from the supplied Dockerfile, which includes the latest version as supported and deployed to the registry. To run via docker, the following commands can be used. (Split into lines for readability) -

docker run -d \
  --name dd \
  -p 60666:60666 \
  -v ~/db:/data \
  jacogr/polkadot-js-client:latest \
    --chain alexander \
    --db-path /data \
    --db-type file \
    --telemetry-name "some-cool-name-here"

Some additional expansion to the above -

docker -d runs the container as a daemon (skip as required)
docker --name specifies the name of the container in docker container ls
docker -p maps the p2p port externally (ensure the firewall is open on this)
docker -v uses the local host path ~/db as the data path, mapping it to the container itself.
For --chain either alexander or dried-danta are built-in options.
--db-type can be either file (default, experimental) or lmdb (experimental, more memory intensive).
Images are deployed to dockerhub, and we try to keep them current.