Wez Furlong
c1849551ed
Still needs to call out to lua for routing and meta updates. May need to parallelize the generation stage if throughput isn't where we want it to be.
kumomta
Concepts
Queuing
Messages are assigned to a queue upon reception. The system can support arbitrarily named queues but the convention is to construct the queue name from some metadata associated with the message:
tenant- some kind of sender or customer identifier or identity derived either from the message itself or authentication of the injection session.campaign- a sender-provided label that can be used to logically group a set of related messages, perhaps generated from the same campaign.- destination domain - the site where the email will be routed
These three pieces of information are combined to produce the name of the queue
in the form campaign:tenant@domain.
Debugging/Tracing
This will launch the server using the policy defined in simple_policy.lua:
KUMOD_LOG=kumod=trace cargo run -p kumod -- --policy simple_policy.lua
Metrics
If the http listener is enabled, the /metrics endpoint will return a set of metrics
for prometheus to scrape.
You can manually review them with curl:
$ curl 'http://127.0.0.1:8000/metrics'
# HELP connection_count connection_count
# TYPE connection_count gauge
connection_count{service="esmtp_listener"} 1
connection_count{service="smtp_client:(alt1|alt2|alt3|alt4)?.gmail-smtp-in.l.google.com."} 0
# HELP delayed_count delayed_count
# TYPE delayed_count gauge
delayed_count{queue="gmail.com"} 1
Contributing
Ensure that the code is formatted before submitting a PR.
You need to install StyLua to format lua:
$ cargo install stylua --features lua54
Then you can format both the rust and the lua code:
$ make fmt
Docker build
To build a lightweight alpine-based docker image:
$ ./docker/kumod/build-docker-image.sh
...
$ docker image ls kumomta/kumod
REPOSITORY TAG IMAGE ID CREATED SIZE
kumomta/kumod latest bbced15ff4d1 3 minutes ago 116MB
You can then run that image; this invocation mounts the kumo
src dir at /config and then the KUMO_POLICY environment
variable is used to override the default /config/policy.lua
path to use the SMTP sink policy script sink.lua,
which will accept and discard all mail:
$ sudo docker run --rm -p 2025:25 \
-v .:/config \
--name kumo-sink \
--env KUMO_POLICY="/config/sink.lua" \
kumomta/kumod
Fuzzing
Some components have fuzzer coverage. To run it, follow the setup from the Rust Fuzz Book
Then:
$ cd crates/rfc5321/
$ cargo +nightly fuzz run parser