This file has notes useful for mox developers. # Code style, guidelines, notes - Keep the same style as existing code. - For Windows: use package "path/filepath" when dealing with files/directories. Test code can pass forward-slashed paths directly to standard library functions, but use proper filepath functions when parameters are passed and in non-test code. Mailbox names always use forward slash, so use package "path" for mailbox name/path manipulation. Do not remove/rename files that are still open. - Not all code uses adns, the DNSSEC-aware resolver. Such as code that makes http requests, like mtasts and autotls/autocert. - We don't have an internal/ directory, really just to prevent long paths in the repo, and to keep all Go code matching *.go */*.go (without matching vendor/). Part of the packages are reusable by other software. Those reusable packages must not cause mox implementation details (such as bstore) to get out, which would cause unexpected dependencies. Those packages also only expose the standard slog package for logging, not our mlog package. Packages not intended for reuse do use mlog as it is more convenient. Internally, we always use mlog.Log to do the logging, wrapping an slog.Logger. # Reusable packages Most non-server Go packages are meant to be reusable. This means internal details are not exposed in the API, and we don't make unneeded changes. We can still make breaking changes when it improves mox: We don't want to be stuck with bad API. Third party users aren't affected too seriously due to Go's minimal version selection. The reusable packages are in apidiff/packages.txt. We generate the incompatible changes with each release. # Web interfaces/frontend The web interface frontends (for webmail/, webadmin/ and webaccount/) are written in strict TypeScript. The web API is a simple self-documenting HTTP/JSON RPC API mechanism called sherpa, https://www.ueber.net/who/mjl/sherpa/. The web API exposes types and functions as implemented in Go, using https://github.com/mjl-/sherpa. API definitions in JSON form are generated with https://github.com/mjl-/sherpadoc. Those API definitions are used to generate TypeScript clients with by https://github.com/mjl-/sherpats/. The JavaScript that is generated from the TypeScript is included in the repository. This makes it available for inclusion in the binary, which is practical for users, and desirable given Go's reproducible builds. When developing, run "make" to also build the frontend code. Run "make jsinstall" once to install the TypeScript compiler into ./node_modules/. There are no other external (runtime or devtime) frontend dependencies. A light-weight abstraction over the DOM is provided by ./lib.ts. A bit more manual UI state management must be done compared to "frameworks", but it is little code, and this allows JavaScript/TypeScript developer to quickly get started. UI state is often encapsulated in a JavaScript object with a TypeScript interface exposing a "root" HTMLElement that is added to the DOM, and functions for accessing/changing the internal state, keeping the UI managable. # Website The content of the public website at https://www.xmox.nl is in website/, as markdown files. The website HTML is generated by website/website.go. The FAQ is taken from README.md, the protocol support table is generated from rfc/index.txt. The website is kept in this repository so a commit can change both the implementation and the documentation on the website. Some of the info in README.md is duplicated on the website, often more elaborate and possibly with a slightly less technical audience. The website should also mostly be readable through the markdown in the git repo. Large files (images/videos) are in https://github.com/mjl-/mox-website-files to keep the repository reasonably sized. The public website serves the content from the "website" branch. After a release release, the main branch (with latest development code and corresponding changes to the website about new features) is merged into the website branch. Commits to the website branch (e.g. for a news item, or any other change unrelated to a new release) is merged back into the main branch. # TLS certificates https://github.com/cloudflare/cfssl is useful for testing with TLS certificates. Create a CA and configure it in mox.conf TLS.CA.CertFiles, and sign host certificates and configure them in the listeners TLS.KeyCerts. Setup a local CA with cfssl, run once: ```sh go install github.com/cloudflare/cfssl/cmd/cfssl@latest go install github.com/cloudflare/cfssl/cmd/cfssljson@latest mkdir -p local/cfssl cd local/cfssl cfssl print-defaults config > ca-config.json # defaults are fine # Based on: cfssl print-defaults csr > ca-csr.json cat <ca-csr.json { "CN": "mox ca", "key": { "algo": "ecdsa", "size": 256 }, "names": [ { "C": "NL" } ] } EOF cfssl gencert -initca ca-csr.json | cfssljson -bare ca - # Generate ca key and cert. # Generate wildcard certificates for one or more domains, add localhost for use with pebble, see below. domains="moxtest.example localhost" for domain in $domains; do cat <wildcard.$domain.csr.json { "key": { "algo": "ecdsa", "size": 256 }, "names": [ { "O": "mox" } ], "hosts": [ "$domain", "*.$domain" ] } EOF cfssl gencert -ca ca.pem -ca-key ca-key.pem -profile=www wildcard.$domain.csr.json | cfssljson -bare wildcard.$domain done ``` Now configure mox.conf to add the cfssl CA root certificate: ``` TLS: CA: AdditionalToSystem: true CertFiles: # Assuming local//config/mox.conf and local/cfssl/. - ../../cfssl/ca.pem [...] Listeners: public: TLS: KeyCerts: # Assuming local//config/mox.conf and local/cfssl/. CertFile: ../../cfssl/wildcard.$domain.pem KeyFile: ../../cfssl/wildcard.$domain-key.pem ``` # ACME https://github.com/letsencrypt/pebble is useful for testing with ACME. Start a pebble instance that uses the localhost TLS cert/key created by cfssl for its TLS serving. Pebble generates a new CA certificate for its own use each time it is started. Fetch it from https://localhost:15000/roots/0, write it to a file, and add it to mox.conf TLS.CA.CertFiles. See below. Setup pebble, run once: ```sh go install github.com/letsencrypt/pebble/cmd/pebble@latest mkdir -p local/pebble cat <local/pebble/config.json { "pebble": { "listenAddress": "localhost:14000", "managementListenAddress": "localhost:15000", "certificate": "local/cfssl/localhost.pem", "privateKey": "local/cfssl/localhost-key.pem", "httpPort": 80, "tlsPort": 443, "ocspResponderURL": "", "externalAccountBindingRequired": false } } EOF ``` Start pebble, this generates a new temporary pebble CA certificate: ```sh pebble -config local/pebble/config.json ``` Write new CA bundle that includes pebble's temporary CA cert: ```sh export CURL_CA_BUNDLE=local/ca-bundle.pem # for curl export SSL_CERT_FILE=local/ca-bundle.pem # for go apps cat /etc/ssl/certs/ca-certificates.crt local/cfssl/ca.pem >local/ca-bundle.pem curl https://localhost:15000/roots/0 >local/pebble/ca.pem # fetch temp pebble ca, DO THIS EVERY TIME PEBBLE IS RESTARTED! cat /etc/ssl/certs/ca-certificates.crt local/cfssl/ca.pem local/pebble/ca.pem >local/ca-bundle.pem # create new list that includes cfssl ca and temp pebble ca. rm -r local/*/data/acme/keycerts/pebble # remove existing pebble-signed certs in acme cert/key cache, they are invalid due to newly generated temp pebble ca. ``` Edit mox.conf, adding pebble ACME and its ca.pem: ``` ACME: pebble: DirectoryURL: https://localhost:14000/dir ContactEmail: root@mox.example TLS: CA: AdditionalToSystem: true CertFiles: # Assuming local//config/mox.conf and local/pebble/ca.pem and local/cfssl/ca.pem. - ../../pebble/ca.pem - ../../cfssl/ca.pem [...] Listeners: public: TLS: ACME: pebble ``` For mail clients and browsers to accept pebble-signed certificates, you must add the temporary pebble CA cert to their trusted root CA store each time pebble is started (e.g. to your thunderbird/firefox testing profile). Pebble has no option to not regenerate its CA certificate, presumably for fear of people using it for non-testing purposes. Unfortunately, this also makes it inconvenient to use for testing purposes. # Messages for testing For compatibility and preformance testing, it helps to have many messages, created a long time ago and recently, by different mail user agents. A helpful source is the Linux kernel mailing list. Archives are available as multiple git repositories (split due to size) at https://lore.kernel.org/lkml/_/text/mirror/. The git repo's can be converted to compressed mbox files (about 800MB each) with: ``` # 0 is the first epoch (with over half a million messages), 12 is last # already-complete epoch at the time of writing (with a quarter million # messages). The archives are large, converting will take some time. for i in 0 12; do git clone --mirror http://lore.kernel.org/lkml/$i lkml-$i.git (cd lkml-$i.git && time ./tombox.sh | gzip >../lkml-$i.mbox.gz) done ``` With the following "tobmox.sh" script: ``` #!/bin/sh pre='' for rev in $(git rev-list master | reverse); do printf "$pre" echo "From sender@host $(date '+%a %b %e %H:%M:%S %Y' -d @$(git show -s --format=%ct $rev))" git show ${rev}:m | sed 's/^>*From />&/' pre='\n' done ``` # Release proces - Gather feedback on recent changes. - Check if dependencies need updates. - Check code if there are deprecated features that can be removed. - Generate apidiff and check if breaking changes can be prevented. Update moxtools. - Update features & roadmap in README.md - Write release notes. - Build and run tests with previous major Go release. - Run tests, including with race detector. - Run integration and upgrade tests. - Run fuzzing tests for a while. - Deploy to test environment. Test the update instructions. - Test mox localserve on various OSes (linux, bsd, macos, windows). - Send and receive email through the major webmail providers, check headers. - Send and receive email with imap4/smtp clients. - Check DNS check admin page. - Check with https://internet.nl. - Add release to the News section of website/index.md. - Create git tag, push code. - Publish new docker image. - Publish signed release notes for updates.xmox.nl and update DNS record. - Publish new cross-referenced code/rfc to www.xmox.nl/xr/. - Create new release on the github page, so watchers get a notification.