It is useful to run the integration tests both against the submitted
dependencies, based on Go module versions from the repository, as well
as the latest ones, to catch integration problems early.
This patch extends the .gitlab-ci.yml configuration to do that, by
optionally passing a flag to "go get" to update the modules.
When modules are configured, go will now attempt to fetch them on build,
using the proxy.
That causes the integration tests run via Docker to fail, because go
build attempts to contact the proxy within the test environment, which
has the external DNS resolvers disabled.
This patch fixes the problem by adjusting the pre-run fetch to use the
new modules system. We fetch the dependencies to the cache so that when
they're needed within the environment, they are present and there's no
need to use the proxy.
The golang image has been updated to use Debian buster. In that version,
msmtp is now setgid, which means glibc sanitizes the environment before
forking and $HOSTALIASES will be ignored, which breaks the tests.
This patch works around the problem by removing the setgid bit from
msmtp.
The integration tests depend on having a DNS server that resolves
"localhost", which is unfortunate but currently unavoidable given
glibc's limitations ($HOSTALIASES only works on DNS-level aliases, and
does not do lookups in /etc/hosts).
Even under docker, this makes the tests depend on the DNS server, and
whether it resolves localhost or not.
In order to make the docker tests more hermetic and isolated from the
environment, this patch introduces a docker entrypoint that, within the
container, will launch minidns and override /etc/resolv.conf to use it.
This guarantees that the tests will be able to resolve localhost, and
also avoid accidental reliance on external DNS zones.
Docker creates intermediate layers on each command (for most commands),
but the COPY was invalidating them too early, every time it runs it was
generating a different layer.
This patch moves the COPY down to the bottom, and adds a bit more
organization to the commands below.
This patch adds DKIM signing using https://github.com/driusan/dkim tools
to the example hook.
It also adds an optional integration test to exercise signing and
verification, and corresponding documentation.
This patch adds a new test, which verifies the TLS tracking.
Because we need to simulate SPF records, and Go does not support fully
intercepting DNS lookups yet, this test relies on dnsmasq to provide a
DNS resolver.
In the future, once Go supports DNS lookup interception, we can get rid
of this additional dependency.
This patch adds a Docker configuration file, to build an image that can
run the integration and stress tests.
It might be used for configuring automated testing infrastructure in
subsequent patches.
