kevroletin / test-task-march-2022

Trial Chain mock

In addition to the design doc, there are also:

• original problem statement;
• simplified stripped task defenition;
• scope - our discussion that we aren't implementing anything complicated;

Build

stack build

Run

Important notes:

• no logging
• hardcoded port 8081
• both server and test start with hardcoded magic "bank" account which contains large quantity of money for testing;

stack run server-exe

You can make sure the server is running using curl:

curl http://localhost:8081/alive

Test

Unit tests and api tests:

stack test

Manual testing

You can generate signed transactions by using ghci:

$ stack repl src/TrialChain/Signature.hs

import Data.Aeson
putStrLn . encode $ _testSignTx "bank" "pedro" 100 ""

{"body": ...

And send requests by REST client of your choice:

PUT http://localhost:8081/tx
Content-type: application/json

{"body":{"from":"bank","to":"pedro","amount":100,"nonce":""},"signature":"signed-by-bank-90d2e36e37adaaa5fbe854f77b02837c"}

Profiling

Done manually. Build sever with profiling, run load-test, analyze profiles manually.

Hunting down memory leaks:

stack run --profile server-exe -- +RTS  -hy -l-agu -RTS
eventlog2html server-exe.eventlog && firefox server-exe.eventlog.html

Hunting down performance bottlenecks:

stack run --profile server-exe -- +RTS -p -RTS
ghc-prof-flamegraph server-exe.prof && firefox firefox server-exe.svg

Running a tester.

stack run load-test-exe

Coding style

Prefer explicit imports. Format using ormolu. Make sure ormolu is runnable and execute sh ./format.sh.

A hack to copy tools from a current workspace into stack's global bin directory and add it to PATH:

copy-stack-tools() {
    stack build --copy-compiler-tool hlint hoogle weeder hindent ghcid ormolu .
}

stackify() {
    compiler_bin=$(stack path --compiler-bin)
    compiler_tools_bin=$(stack path --compiler-tools-bin)
    if [ ! -d $compiler_tools_bin ]; then
        copy-stack-tools
    fi
    if [ ! -d $compiler_bin ]; then
        stack build --install-ghc
    fi
    PATH=$compiler_bin:$compiler_tools_bin:$PATH
}