All the fancy things you can do with flexible dependency management

New APIs of coursier (high level, Java, sbt)

coursier install and coursier publish commands

Transcript

1. All the fancy things you can do with flexible dependency mgmt Alexandre Archambault @alxarchambault (not a typo) github.com/alexarchambault Scala Center
2. get-coursier.io 2015 (!) – library + CLI – sbt plugin came later 2017: 1.0
3. get-coursier.io 2015 (!) – library + CLI – sbt plugin came later 2017: 1.0
4. Plan – New APIs: high-level, Java, sbt API – "Enterprise" features (better authentication, mirrors, …) – install command – publish command – Demo!
5. APIs
6. High-level API
7. High-level API
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23. High-level API
24. Purity or getting things done? Both! Pass all the inputs explicitly if you want to Get results in an IO Relies on all the defaults Get results or an exception, synchronously
25. Former API
26. Former API
27. Java API Minimum surface area Even more conservative in terms of binary compatibility Shades coursier, scala-library too Goals – Java users? – Lower chances of conflicts (scalafmt- dynamic, Ammonite?, dotty?)
28. APIs High-level API – Simpler API, closer to the CLI, while still retaining purity Java API – Stability, binary compatibility Also – lm-coursier (implementing sbt/library-management)
29. sbt API
30. Early implementations
31. sbt-coursier sbt coursier sbt-lm sbt-coursier sbt lm-coursier sbt-lm coursier lm-coursier-shaded coursier sbt sbt-lm sbt-lm-coursier
32. Enterprise features
33. Rules Enforce constraints Fix them automatically, or fail Available – Strict – DontBumpRootDependencies – SameVersion Resolution strategy – Try to fix – Warn – Fail
34. Reworked authentication Read credentials from file Pass on redirect (or not) Restrict to https (default) … For now: applied by host
35. Mirrors Substitute internal repositories to Central, etc. For the coursier CLI mostly
36. install
37. Motivation Distribute apps just like libraries – No launchers to handle / push / distribute / download… – But (slightly) more cumbersome command for end-users
38. Even more complex for more advanced apps – dotty-repl – scalac – mill? – …
39. Couldn't we just do $ coursier install dotty-repl $ coursier launch scalafmt:1.6.0-RC4
40. install demo
41. App descriptions – in JSON at specific paths or URLs https://github.com/coursier/ apps/blob/extras/apps.json – from "channels" (JAR published on a Maven repository, containing JSON files for multiple apps) Default channel: io.get-coursier:apps, via github.com/coursier/apps
42. install Installs – JVM apps – scala-native apps (built locally from Maven artifacts) – graalvm native image generation Updates – changes in source (JSON) – new artifacts (if latest.* or version interval) Only relies on the coursier cache – no git clone, …
43. publish
44. Disclaimer sbt-ci-release (harnessing sbt-git, sbt-sonatype, sbt-pgp, sbt-dynver) mill basically work fine
45. Workflow Build tool writes (all) artifacts to a directory Then the publish command takes over, and publishes that
46. Principle Take one or more "sources" – Think sbt projects, existing directories with pre-defined structure, … Transform them – Adjust organization, version, etc. (changes POM files, paths) – Add missing metadata (maven-metadata.xml) – Add missing checksums, signatures – Snapshot versioning Write / push them somewhere – In a local directory, to a remote repository, …
47. install + publish demo