devshell tools

This is a collection of tools for creating dev environments with nix flakes. It doesn't create something new, but relies on NixOS modules and nixpkgs. The flake provides services that are only a wrapper around existing ones with an opinionated config towards ease of use in a dev environment.

Usage

A template is provided to get started:

nix flake init -t github:eikek/devshell-tools

The flake provides several modules that can be used selectively. There are two functions that create vm or a container with all modules included. You could use it like this:

  inputs.devshell-tools.url = ...
  ...
  nixosConfigurations = {
    dev-vm = devshell-tools.lib.mkVm {
      system = "x86_64-linux";
      modules = [
        {
          services.dev-solr.enable = true;
          services.dev-email.enable = true;
          services.dev-postgres.enable = true;
          services.dev-mariadb.enable = true;
          services.openapi-docs.enable = true;
        }
      ];
    };
    container = devshell-tools.lib.mkContainer {
      system = "x86_64-linux";
      modules = [
        {
          services.dev-solr.enable = true;
          services.dev-email.enable = true;
          services.dev-postgres.enable = true;
          services.dev-mariadb.enable = true;
          services.openapi-docs.enable = true;
        }
      ];
    };
  }

The vm has a root account with password root. Additionally, a passwordless ssh key is configured.

In your module you can then enable and configure the provided modules.

The vm adds port-forwarding to the services by default. This can be changed in your module using the supplied shortcuts:

port-forward.ssh = 10022;
port-forward.dev-postgres = 6543;
port-forward.dev-smtp = 1587;
port-forward.dev-imap = 1143;
port-forward.dev-webmail = 8080;
…

With this, it is possible to ssh into the vm from port 10022 on the host for example. Of course, the standard virtualisation.forwardPorts can be used as well.

Content

Packages

solr

Nixpkgs dropped solr. So a simple package is included here.

swagger-ui

Packages the swagger-ui npm package to render openAPI specs in the browser. It is used by the openapi-docs package and module.

openapi-docs

Uses swagger-ui to provide a simple script that accepts an url to an openapi specification and will render its documentation in the browser by starting a simple http server.

vm scripts

A collection of small scripts to manage development vms that are defined as nixosConfigurations in your flake. They are just some convenience shortcuts to a bit longer nix commands.

For example, vm-build runs nix build ".#nixosConfigurations.$name.config.system.build.vm" where $name is the value of DEV_VM environment variable, or the default dev-vm. This name must have a corresponding nixosConfiguration to build.

The vm-scripts all start with vm- for easier lookup. They are provided as vm-scripts attribute set in legacyPackages so they can be installed all at once.

Example use:

inputs.devshell-tools.url = …

devShells.default = {
  buildInputs = builtins.attrValues devshell-tools.legacyPackages.${system}.vm-scripts;
};

postgres-fg

This package provides a simple shell script to start a postgresql server given any data directory and port. It might be handy for quickly running postgres ad-hoc.

cnt scripts

A collection of small scripts to manage dev containers that are defined as nixosConfigurations in your flake.

For example, cnt-recreate deletes an existing container, creates it anew and starts it. The container name is taken from the DEV_CONTAINER environment variable or defaults to dev-cnt. If no container name is given it uses either dev-cnt or container if dev-cnt is not defined in nixosConfigurations.

The cnt-scripts all start with cnt- for easier lookup. They are provided as cnt-scripts attribute set in legacyPackages so they can be installed all at once.

Example use:

inputs.devshell-tools.url = …

devShells.default = {
  buildInputs = builtins.attrValues devshell-tools.legacyPackages.${system}.cnt-scripts;
};

Lib

The lib output has a few function that might be interesting to use in devshells.

• installScript: Takes a script file as input, makes it executable and puts it into the store behind a bin/ path so it will be in your environment. Like writeScript but referencing some file instead of defining inline.

• mkVm and mkContainer: Given a list of additional modules (and system…), it creates a NixOS container or vm that has all packages and modules of this flake included.

Modules

solr

There is a very simple module that allows to run solr on systemd. It allows only a few configurations, but should be enough for development.

postgresql

Enables PostgreSQL with settings to be able to connect to it from anywhere. It creates a user dev with password dev.

Additionally, pgweb is enabled by default on port 5433 for the first database specified for dev-postgres or the one given to the pgweb config.

mariadb

Enables MariaDB with settings to be able to connect to it easily. It creates a user dev with password dev.

email

The email modules configures a complete email setup: exim for smtp, dovecot2 for imap and roundcube for webmail.

The services are configured to allow anyone to login while the password is the same as the user name.

Users are created on demand in dovecot. So in order to be able to send mail to a user, you need to login once so dovecot can create the user directory.

Roundcube is configured inside nginx to access the mails of all users. It connects to the internal dovecot and exim services. It has been patched to allow non-standard email addresses, so it can send to myuser@localhost for example and it is then possible to test bad input more easily.

redis

Sets up a single redis instance with global access.

minio

Sets up minio with the defaults, root user "minioadmin" and same password.

OpenAPI Docs

Given an URL to a open api spec, sets up nginx to serve the rendered documentation page.

Jena Fuseki

Sets up a fuseki rdf server.

Dev

Build the test container for trying out stuff:

nix build .#nixosConfigurations.test.config.system.build.toplevel

Run the test, create a container and start it:

sudo nixos-container create devshellt --flake .#test
sudo nixos-container start devshellt