Extracting emitted events (logs) from geth transaction trace (debug_traceCall) - ethereum

Question

When using debug_traceCall, I get a low-level EVM trace of all opcodes and state changes during the execution. This is excessively detailed. When I use default callTracer, I can get a much nicer call tree. However, neither way I cannot seem to be able to extract the emitted events from the trace. I can see them in the trace (LOG* opcodes) however there is no easy way to actually parse them to something "readable" (along with values and originating address) There must be a way to get the logs - any ideas?
Eg. this is what Etherscan shows https://etherscan.io/tx-decoder?tx=0x3e3ad35fda1fddd9e154b3860b50371a1acd2fdb4f27f897e234846522bde732 (see Emitted Events section)

Answer 1

So I figured this myself - I created a custom JavaScript tracer for geth that is passed to geth in 3rd param to debug_traceCall (see provided API reference by the link):
{
data: [],
fault: function (log) {
},
step: function (log) {
var topicCount = (log.op.toString().match(/LOG(\d)/) || [])[1];
if (topicCount) {
var res = {
address: log.contract.getAddress(),
data: log.memory.slice(parseInt(log.stack.peek(0)), parseInt(log.stack.peek(0)) + parseInt(log.stack.peek(1))),
};
for (var i = 0; i < topicCount; i++)
res['topic' + i.toString()] = log.stack.peek(i + 2);
this.data.push(res);
}
},
result: function () {
return this.data;
}
}
This tracer is executed by geth for each operation in the trace. Essentially what it does:
check if this is one of LOG0, LOG1, LOG2, LOG3 or LOG4 EVM opcodes
extract contract address from current contract
extract default topic0 and subsequent topics (if any)
extract additional event data from memory (note: stack[0] is offset, stack[1] is data size)
Passing the tracer to geth looks like this:
res = await ethersProvider.send('debug_traceCall', [{
from: tx.from,
to: tx.to,
gas: BigNumber.from(tx.gas)._hex.replace('0x0', '0x'),
gasPrice: BigNumber.from(tx.gasPrice)._hex.replace('0x0', '0x'),
value: BigNumber.from(tx.value)._hex.replace('0x0', '0x'),
data: tx.input
}, "latest", {
tracer: "{\n" +
" data: [],\n" +
" fault: function (log) {\n" +
" },\n" +
" step: function (log) {\n" +
" var topicCount = (log.op.toString().match(/LOG(\\d)/) || [])[1];\n" +
" if (topicCount) {\n" +
" var res = {\n" +
" address: log.contract.getAddress(),\n" +
" data: log.memory.slice(parseInt(log.stack.peek(0)), parseInt(log.stack.peek(0)) + parseInt(log.stack.peek(1))),\n" +
" };\n" +
" for (var i = 0; i < topicCount; i++)\n" +
" res['topic' + i.toString()] = log.stack.peek(i + 2);\n" +
" this.data.push(res);\n" +
" }\n" +
" },\n" +
" result: function () {\n" +
" return this.data;\n" +
" }\n" +
"}",
enableMemory: true,
enableReturnData: true,
disableStorage: true
}])