This diff creates a new package under netx called tracex that
contains everything we need to perform measurements using events
tracing and postprocessing (which is the technique with which
we implement most network experiments).
The general idea here is to (1) create a unique package out of
all of these packages; (2) clean up the code a bit (improve tests,
docs, apply more recent code patterns); (3) move the resulting
code as a toplevel package inside of internal.
Once this is done, netx can be further refactored to avoid
subpackages and we can search for more code to salvage/refactor.
See https://github.com/ooni/probe/issues/2121
This diff refactors the DNSTransport model to receive in input a DNSQuery and return in output a DNSResponse.
The design of DNSQuery and DNSResponse takes into account the use case of a transport using getaddrinfo, meaning that we don't need to serialize and deserialize messages when using getaddrinfo.
The current codebase does not use a getaddrinfo transport, but I wrote one such a transport in the Websteps Winter 2021 prototype (https://github.com/bassosimone/websteps-illustrated/).
The design conversation that lead to producing this diff is https://github.com/ooni/probe/issues/2099
This diff addresses two items of https://github.com/ooni/probe/issues/1956:
> - [ ] we can remove legacy names from `./internal/engine/netx/resolver/legacy.go`
>
> - [ ] we can remove `DialTLSContext` from `./internal/engine/netx/resolver/tls_test.go`
More cleanups may follow.
This is how I did it:
1. `git clone https://github.com/ooni/probe-engine internal/engine`
2. ```
(cd internal/engine && git describe --tags)
v0.23.0
```
3. `nvim go.mod` (merging `go.mod` with `internal/engine/go.mod`
4. `rm -rf internal/.git internal/engine/go.{mod,sum}`
5. `git add internal/engine`
6. `find . -type f -name \*.go -exec sed -i 's@/ooni/probe-engine@/ooni/probe-cli/v3/internal/engine@g' {} \;`
7. `go build ./...` (passes)
8. `go test -race ./...` (temporary failure on RiseupVPN)
9. `go mod tidy`
10. this commit message
Once this piece of work is done, we can build a new version of `ooniprobe` that
is using `internal/engine` directly. We need to do more work to ensure all the
other functionality in `probe-engine` (e.g. making mobile packages) are still WAI.
Part of https://github.com/ooni/probe/issues/1335
