Add newPendingTransactions and syncing to RSKj eth_subscribe JSON-RPC Method

[Vovchyk]

Description

Implemented new pending transactions and sync transactions. Both behave the same as when geth is attached (subscribe sync start and end are events have replicated functionality with geth attaching to web3 endpoints). 100% code coverage on new files and increased test coverage percentage in co.rsk.rpc.modules.eth.subscribe package (attached master and current branch code coverage report for reference). Followed existing patterns.

Originated from #1530

Motivation and Context

Resolves rsksmart/rsk-gitcoin-hackathon-2021#15 & resolves rsksmart/rsk-gitcoin-hackathon-2021#16

Personally my participation in the hackathon was driven by:

Interested in cryptocurrency.
Want to continue honing skills in open source software.

How Has This Been Tested?

Subscribe Syncing:

1. Start rskj node that has not synchronized (clear local data if needed) with --testnet
2. Connect to rskj ws @ ws://localhost:4445/websocket
3. Make following request:

JSONRPC Request: {"jsonrpc": "2.0", "method":"eth_subscribe","params":["syncing"],"id":1}

4. Once the node begins syncing you will see syncing started.
5. Once the node stops syncing you will see synching ended.

Response examples:
Sync started:
{ "jsonrpc": "2.0", "method": "eth_subscription", "params": { "subscription": "0xfb93f2548a59febf37e77974c65439b5", "result": { "syncing": true, "status": { "startingBlock": 0, "currentBlock": 0, "highestBlock": 24255 } } } }
Sync ended:
{ "jsonrpc": "2.0", "method": "eth_subscription", "params": { "subscription": "0xfb93f2548a59febf37e77974c65439b5", "result": { "syncing": false, } }

Below is an example of same behavior being displayed in geth as in new subscribe functionality (Geth is attached to the RSKj node)

• The top window is RSKj node running in intelliJ
• The bottom left window is attached geth node and manually calling eth.syncing
• The bottom right window is a websocket client subscribed to RSKj syncing method

Subscribe new pending transactions

1. Start rskj node with --regtest
2. Install geth then attach geth with geth attach http://127.0.0.1:4444
3. Connect to rskj ws @ ws://localhost:4445/websocket
4. Make the following request: {"jsonrpc": "2.0", "method":"eth_subscribe","params":["newPendingTransactions"],"id":1}
5. In geth console send a transaction: eth.sendTransaction({from:eth.accounts[1], to:"0xf6e443fd1c869c6a25d18a9866f3a6c7f8dfb703", value: web3.toWei(300000000000, "ether")})
6. You should see websocket response:
   { "jsonrpc": "2.0", "method": "eth_subscription", "params": { "subscription": "0x9eec892ee10d588f63a3298dc28ca9ca", "result": "0xe8959f138720de78ef14c5688176c89dd8096546ca04bda698e3ee84e7ff67b1" } }

Below is an example of sending a transaction using attached geth

• The top window is RSKj node running in intelliJ
• The bottom left window is attached geth node which will send the transaction
• The bottom right window is a websocket client subscribed to RSKj newPendingTransactions method

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• [] My change requires a change to the documentation.
• I have updated the documentation accordingly.
• Tests for the changes have been added (for bug fixes / features)
• Requires Activation Code (Hard Fork)

• Other information:

[Vovchyk]

pipeline: run

[Vovchyk]

pipeline: run

[Vovchyk]

pipeline: run

[Vovchyk]

pipeline: run

[Vovchyk]

pipeline: run

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

99.2% Coverage
0.0% Duplication

[nagarev]

LGTM