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devenv 0.6: Generating containers and instant shell activation

After about two months of active development, I'm happy to announce devenv 0.6 is ready.

This release comes with the most notable improvements based on the feedback from existing users:

Generating containers

While devenv shell provides a simple native developer environment experience, devenv container <name> allows you to generate and copy OCI container into a registry.

Containers are a great way to distribute ready-made applications, leveraging platforms like to deploy them into production.

An example for Ruby:

  name = "simple-ruby-app";

  languages.ruby.enable = true;
  languages.ruby.version = "3.2.1";

We can generate a container called shell that enters the environment, copy it to the local Docker daemon and run it:

$ devenv container shell --docker-run
(devenv) bash-5.2# ruby --version
ruby 3.2.1 (2023-02-08 revision 31819e82c8) [x86_64-linux]

You can read more in the new Containers section of the documentation, specifically:

Instant shell activation

Especially monorepo developer environments can sometimes be even a few gigabytes of size, taking a few seconds for the environment to be activated.

A developer environment should only be built when something changes and if not, the environment can be used instantly using a cached snapshot.

With the latest integration, we've finally reached that goal by making caching work properly (it will even watch each of your imports for changes!).

Migrating from an older devenv

Make sure to use the latest .envrc from devenv init and for everyone on the team to upgrade to devenv 0.6.

In the near future we'll experiment to improve devenv shell experience.

Hosts and certificates

Hosts and certificates can now be specified declaratively:

{ pkgs, config, ... }:

  certificates = [

  hosts."" = "";

  services.caddy.enable = true;
  services.caddy.virtualHosts."" = {
    extraConfig = ''
      tls ${config.env.DEVENV_STATE}/mkcert/ ${config.env.DEVENV_STATE}/mkcert/
      respond "Hello, world!"

And when you run devenv up to start the processes, these hosts and certificates will be provisioned locally.

allowUnfree and overlays

For example in devenv.yaml:

allowUnfree: true
    url: github:NixOS/nixpkgs/nixpkgs-unstable
    url: github:oxalica/rust-overlay
      - default

Will allow building unfree software and wire up default overlay into pkgs from rust-overlay.

Migrating from an older devenv

Make sure everyone on the team upgrades to devenv 0.6.

Languages changelog

  • Python: Added support for virtualenv creation and poetry by bobvanderlinden.
  • Ruby: First-class support for setting version or versionFile by bobvanderlinden.
  • Go: Received significant improvements by shyim.
  • PHP: Added first-class support for setting version to make it easier to set extensions by shyim.
  • Scala: Now allows changing the package and offers scala-cli as an option if the JDK is too old by domenkozar.
  • R: Added an option to specify the package by adfaure.
  • Rust: Can now find headers for darwin frameworks by domenkozar.
  • OCaml: Allowed using a different version of OCaml by ankhers.
  • Tex Live: Added support by BurNiinTRee.
  • Swift: Added support by domenkozar.
  • Raku: Added support by 0pointerexception.
  • Gawk: Added support by 0pointerexception.
  • Racket: Added support by totoroot.
  • Dart: Added support by domenkozar.
  • Julia: Added support by domenkozar.
  • Crystal: Added support by bcardiff.
  • Unison: Added support by ereslibre.
  • Zig: Added support by ereslibre.
  • Deno: Added support by janathandion.

Services changelog

  • Cassandra: Added by ankhers.

  • CouchDB: Added by MSBarbieri.

  • MariaDB: Corrected user and database handling by jochenmanz.

  • MinIO: Now allows specifying what buckets to provision by shyim.

Fixed issues and other improvements

  • process-compose: Faster shutdown, restart on failure by default, escape env variables properly by thenonameguy.

  • Support assertions in modules by bobvanderlinden.

  • Fix overmind root by domenkozar.

  • Make devenv info output pluggable from devenv modules by domenkozar.

  • Expand the flake guide by sandydoo.

  • Set LOCALE_ARCHIVE when missing by sandydoo.

  • Numerous option documentation fixes by sandydoo.

  • Fix starship integration with a custom config by domenkozar.

  • Test direnv integration with strict bash mode by stephank.

  • Add a shim devenv for flakes integration by rgonzalez.