As part of trying to make the inputs and outputs of the evm subcommands
more streamlined and aligned, this PR modifies how `evm t8n` manages
output-files.
Previously, we do a kind of wonky thing where between each transaction,
we invoke a `getTracer` closure. In that closure, we create a new
output-file, a tracer, and then make the tracer stream output to the
file. We also fiddle a bit to ensure that the file becomes properly
closed.
It is a kind of hacky solution we have in place. This PR changes it, so
that from the execution-pipeline point of view, we have just a regular
tracer. No fiddling with re-setting it or closing files.
That particular tracer, however, is a bit special: it takes care of
creating new files per transaction (in the tx-start-hook) and closing
(on tx-end-hook). Also instantiating the right type of underlying
tracer, which can be a json-logger or a custom tracer.
---------
Co-authored-by: Gary Rong <garyrong0905@gmail.com>
Here we add a Go API for running tracing plugins within the main block import process.
As an advanced user of geth, you can now create a Go file in eth/tracers/live/, and within
that file register your custom tracer implementation. Then recompile geth and select your tracer
on the command line. Hooks defined in the tracer will run whenever a block is processed.
The hook system is defined in package core/tracing. It uses a struct with callbacks, instead of
requiring an interface, for several reasons:
- We plan to keep this API stable long-term. The core/tracing hook API does not depend on
on deep geth internals.
- There are a lot of hooks, and tracers will only need some of them. Using a struct allows you
to implement only the hooks you want to actually use.
All existing tracers in eth/tracers/native have been rewritten to use the new hook system.
This change breaks compatibility with the vm.EVMLogger interface that we used to have.
If you are a user of vm.EVMLogger, please migrate to core/tracing, and sorry for breaking
your stuff. But we just couldn't have both the old and new tracing APIs coexist in the EVM.
---------
Co-authored-by: Matthieu Vachon <matthieu.o.vachon@gmail.com>
Co-authored-by: Delweng <delweng@gmail.com>
Co-authored-by: Martin HS <martin@swende.se>
Martin HS
Sina M