nix/modules/virtualisation/podman-pod.nix

# Save this as podman-pod.nix
{
  config,
  lib,
  pkgs,
  ...
}:

with lib;

let
  cfg = config.services.podmanPods;

  # Get the options from the original oci-containers module
  containerOptions = (
    filterAttrs (
      n: v: n != "definition"
    ) config.virtualisation.oci-containers.containers.type.getSubOptions
  );

  # Add our enable option
  extendedContainerOptions = containerOptions // {
    enable = mkEnableOption "Enable this container";
  };

  podOptions =
    { name, config, ... }:
    {
      options = {

        name = mkOption {
          type = types.str;
          description = "Name of the pod";
        };

        ports = mkOption {
          type = types.listOf types.str;
          default = [ ];
          description = "List of port mappings (e.g. ['8080:80'])";
        };

        containers = mkOption {
          type = types.attrsOf (types.submodule { options = extendedContainerOptions; });
          default = { };
          description = "Attribute set of OCI container configurations for this set";
        };

      };
    };

  createPodScript =
    name: podDef:
    let
      podDefinitionString = builtins.toJSON { inherit (podDef) ports; };
    in
    pkgs.writeScript "manage-pod-${name}.sh" ''
      #! /bin/sh
      set -e

      POD_NAME="${name}"
      POD_DEFINITION="${podDefinitionString}"

      create_pod() {
        podman pod create --name "$POD_NAME" \
          ${concatStringsSep " " (map (port: "--publish ${port}") podDef.ports)}
      }

      if podman pod exists "$POD_NAME"; then
        CURRENT_CONFIG=$(podman pod inspect "$POD_NAME" | jq -c '{ports: .[0].InfraConfig.PortBindings | to_entries | map("\(.value[0].HostPort):\(.key | split("/")[0])") | sort'})
        echo "POD_DEFINITION: $POD_DEFINITION"
        echo "CURRENT_CONFIG: $CURRENT_CONFIG"
        if [ "$CURRENT_CONFIG" != "$POD_DEFINITION" ]; then
          echo "Pod configuration has changed. Recreating pod..."
          podman pod rm -f "$POD_NAME"
          create_pod
        else
          echo "Pod configuration unchanged."
        fi
      else
        echo "Pod does not exist. Creating..."
        create_pod
      fi
    '';

  enabledContainers = lib.flatten (
    mapAttrs (
      podName: podConfig: filterAttrs (name: value: value.enable or true) podConfig.containers
    ) cfg
  );

in
{
  options.services.podmanPods = mkOption {
    type = types.attrsOf (types.submodule podOptions);
    default = { };
    description = "Podman pods to create";
  };

  config = mkIf (cfg != { }) {
    virtualisation.podman.enable = true;
    virtualisation.oci-containers.backend = "podman";

    environment.systemPackages = [ pkgs.jq ];

    virtualisation.oci-containers.containers = enabledContainers;

    # virtualisation.oci-containers.containers = listToAttrs (flatten (mapAttrsToList
    #   (podName: podDef:
    #     mapAttrs
    #       (containerName: containerDef:
    #         filterAttrs (attrName: attrValue: attrName != "enable") containerDef
    #         # nameValuePair "${podName}-${containerName}" ({
    #         #   inherit (containerDef) image;
    #         #   extraOptions = [ "--pod=${podName}" ] ++ containerDef.extraOptions;
    #         # })
    #       )
    #       podDef.containers
    #   )
    #   cfg));

    # virtualisation.oci-containers.containers = lib.flatten
    #   (mapAttrs
    #     (podName: podConfig:
    #       mapAttrs
    #         (containerName: containerConfig:
    #           filterAttrs (attrName: attrValue: attrName != "enable") containerConfig
    #         )
    #         (filterAttrs (name: value: value.enable) podConfig.containers)
    #     )
    #     (filterAttrs (podName: podConfig: podConfig.enable) cfg)
    #   );
    # mapAttrs
    #   (name: value:
    #   filterAttrs (n: v: n != "enable") value
    #   )
    #   (filterAttrs (name: value: value.enable) cfg.containers);

    networking.firewall.allowedTCPPorts = flatten (
      mapAttrsToList (
        name: podDef: map (portMapping: lib.toInt (lib.head (lib.splitString ":" portMapping))) podDef.ports
      ) cfg
    );

    systemd.services =
      let
        podServices = mapAttrs' (
          name: podDef:
          nameValuePair "podman-pod-${name}" {
            description = "Manage Podman pod: ${name}";
            serviceConfig = {
              Type = "oneshot";
              ExecStart = "${createPodScript name podDef}";
            };
            path = [
              pkgs.jq
              pkgs.podman
            ];
            after = [ "network.target" ];
            wantedBy = [ "multi-user.target" ];
          }
        ) cfg;
        containerServices = mapAttrs' (
          name: container:
          nameValuePair "podman-${name}" {
            after = [ "podman-pod-${lib.head (lib.splitString "-" name)}.service" ];
            requires = [ "podman-pod-${lib.head (lib.splitString "-" name)}.service" ];
            partOf = [ "podman-pod-${lib.head (lib.splitString "-" name)}.service" ];
          }
        ) config.virtualisation.oci-containers.containers;
      in
      podServices // containerServices;
  };
}