ClanModules: Add docs and api to retrieve metadata

checks/installation/flake-module.nix

@@ -12,7 +12,7 @@
       { lib, modulesPath, ... }:
       {
         imports = [
-          self.clanModules.disk-layouts
+          "${self}/nixosModules/disk-layouts"
           (modulesPath + "/testing/test-instrumentation.nix") # we need these 2 modules always to be able to run the tests
           (modulesPath + "/profiles/qemu-guest.nix")
         ];

clanModules/borgbackup-static/README.md

@@ -1,10 +1,11 @@
-Statically configure borgbackup with sane defaults.
 ---
-This module implements the `borgbackup` backend and implements sane defaults 
+description = "Statically configure borgbackup with sane defaults."
+---
+This module implements the `borgbackup` backend and implements sane defaults
 for backup management through `borgbackup` for members of the clan.
 
 Configure target machines where the backups should be sent to through `targets`.
 
 Configure machines that should be backuped either through `includeMachines`
-which will exclusively add the included machines to be backuped, or through 
+which will exclusively add the included machines to be backuped, or through
 `excludeMachines`, which will add every machine except the excluded machine to the backup.

clanModules/borgbackup/README.md

@@ -1,2 +1,7 @@
-Efficient, deduplicating backup program with optional compression and secure encryption.
+---
----
+description = "Efficient, deduplicating backup program with optional compression and secure encryption."
+categories = ["backup"]
+---
+Long explanations1
+Long explanations2
+Long explanations3

clanModules/borgbackup/default.nix

@@ -27,54 +27,51 @@ let
       exit 1
     fi
   '';
-
-  # Each .nix file in the roles directory is a role
-  # TODO: Helper function to set available roles within module meta.
-  roles =
-    if builtins.pathExists ./roles then
-      lib.pipe ./roles [
-        builtins.readDir
-        (lib.filterAttrs (_n: v: v == "regular"))
-        lib.attrNames
-        (map (fileName: lib.removeSuffix ".nix" fileName))
-      ]
-    else
-      null;
-
-  # TODO: make this an interface of every module
-  # Maybe load from readme.md
-  metaInfoOption = lib.mkOption {
-    readOnly = true;
-    description = ''
-      Meta is used to retrieve information about this module.
-
-      - `availableRoles` is a list of roles that can be assigned via the inventory.
-      - `category` is used to group services in the clan marketplace.
-      - `description` is a short description of the service for the clan marketplace.
-    '';
-    default = {
-      description = "Borgbackup is a backup program. Optionally, it supports compression and authenticated encryption.";
-      availableRoles = roles;
-      category = "backup";
-    };
-    type = lib.types.submodule {
-      options = {
-        description = lib.mkOption { type = lib.types.str; };
-        availableRoles = lib.mkOption { type = lib.types.nullOr (lib.types.listOf lib.types.str); };
-        category = lib.mkOption {
-          description = "A category for the service. This is used to group services in the clan ui";
-          type = lib.types.enum [
-            "backup"
-            "network"
-          ];
-        };
-      };
-    };
-  };
 in
+# Each .nix file in the roles directory is a role
+# TODO: Helper function to set available roles within module meta.
+# roles =
+#   if builtins.pathExists ./roles then
+#     lib.pipe ./roles [
+#       builtins.readDir
+#       (lib.filterAttrs (_n: v: v == "regular"))
+#       lib.attrNames
+#       (map (fileName: lib.removeSuffix ".nix" fileName))
+#     ]
+#   else
+#     null;
+# TODO: make this an interface of every module
+# Maybe load from readme.md
+# metaInfoOption = lib.mkOption {
+#   readOnly = true;
+#   description = ''
+#     Meta is used to retrieve information about this module.
+#     - `availableRoles` is a list of roles that can be assigned via the inventory.
+#     - `category` is used to group services in the clan marketplace.
+#     - `description` is a short description of the service for the clan marketplace.
+#   '';
+#   default = {
+#     description = "Borgbackup is a backup program. Optionally, it supports compression and authenticated encryption.";
+#     availableRoles = roles;
+#     category = "backup";
+#   };
+#   type = lib.types.submodule {
+#     options = {
+#       description = lib.mkOption { type = lib.types.str; };
+#       availableRoles = lib.mkOption { type = lib.types.nullOr (lib.types.listOf lib.types.str); };
+#       category = lib.mkOption {
+#         description = "A category for the service. This is used to group services in the clan ui";
+#         type = lib.types.enum [
+#           "backup"
+#           "network"
+#         ];
+#       };
+#     };
+#   };
+# };
 {
 
-  options.clan.borgbackup.meta = metaInfoOption;
+  # options.clan.borgbackup.meta = metaInfoOption;
 
   options.clan.borgbackup.destinations = lib.mkOption {
     type = lib.types.attrsOf (

clanModules/deltachat/README.md

@@ -1,4 +1,5 @@
-Email-based instant messaging for Desktop.
+---
+description = "Email-based instant messaging for Desktop."
 ---
 
 !!! warning "Under construction"

clanModules/disk-layouts/README.md

@@ -1,2 +0,0 @@
-Automatically format a disk drive on clan installation
----

clanModules/ergochat/README.md

@@ -1,2 +1,3 @@
-A modern IRC server
+---
+description = "A modern IRC server"
 ---

clanModules/flake-module.nix

@@ -1,9 +1,6 @@
 { ... }:
 {
   flake.clanModules = {
-    disk-layouts = {
-      imports = [ ./disk-layouts ];
-    };
     borgbackup = ./borgbackup;
     borgbackup-static = ./borgbackup-static;
     deltachat = ./deltachat;

clanModules/localbackup/README.md

@@ -1,2 +1,3 @@
-Automatically backups current machine to local directory.
+---
+description = "Automatically backups current machine to local directory."
 ---

clanModules/localsend/README.md

@@ -1,2 +1,3 @@
-Securely sharing files and messages over a local network without internet connectivity.
+---
+description = "Securely sharing files and messages over a local network without internet connectivity."
 ---

clanModules/matrix-synapse/README.md

@@ -1,2 +1,3 @@
-A federated messaging server with end-to-end encryption.
+---
+description = "A federated messaging server with end-to-end encryption."
 ---

clanModules/moonlight/README.md

@@ -1,2 +1,3 @@
-A desktop streaming client optimized for remote gaming and synchronized movie viewing.
+---
+description = "A desktop streaming client optimized for remote gaming and synchronized movie viewing."
 ---

clanModules/postgresql/README.md

@@ -1,2 +1,3 @@
-A free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance.
+---
+description = "A free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance."
 ---

clanModules/root-password/README.md

@@ -1,4 +1,5 @@
-Automatically generates and configures a password for the root user.
+---
+description = "Automatically generates and configures a password for the root user."
 ---
 
 After the system was installed/deployed the following command can be used to display the root-password:

clanModules/sshd/README.md

@@ -1,2 +1,3 @@
-Enables secure remote access to the machine over ssh
+---
+description = "Enables secure remote access to the machine over ssh"
 ---

clanModules/static-hosts/README.md

@@ -1,2 +1,3 @@
-Statically configure the host names of machines based on their respective zerotier-ip.
+---
+description = "Statically configure the host names of machines based on their respective zerotier-ip."
 ---

clanModules/sunshine/README.md

@@ -1,2 +1,3 @@
-A desktop streaming server optimized for remote gaming and synchronized movie viewing.
+---
+description = "A desktop streaming server optimized for remote gaming and synchronized movie viewing."
 ---

clanModules/syncthing-static-peers/README.md

@@ -1,2 +1,3 @@
-Statically configure syncthing peers through clan
+---
+description = "Statically configure syncthing peers through clan"
 ---

clanModules/syncthing/README.md

@@ -1,4 +1,5 @@
-A secure, file synchronization app for devices over networks, offering a private alternative to cloud services.
+---
+description = "A secure, file synchronization app for devices over networks, offering a private alternative to cloud services."
 ---
 ## Usage
 

clanModules/thelounge/README.md

@@ -1,2 +1,3 @@
-Modern web IRC client
+---
+description = "Modern web IRC client"
 ---

clanModules/trusted-nix-caches/README.md

@@ -1,2 +1,3 @@
-This module sets the `clan.lol` and `nix-community` cache up as a trusted cache.
+---
+description = "This module sets the `clan.lol` and `nix-community` cache up as a trusted cache."
 ----

clanModules/user-password/README.md

@@ -1,4 +1,5 @@
-Automatically generates and configures a password for the specified user account.
+---
+description = "Automatically generates and configures a password for the specified user account."
 ---
 
 If setting the option prompt to true, the user will be prompted to type in their desired password.

clanModules/xfce/README.md

@@ -1,2 +1,3 @@
-A lightweight desktop manager
+---
+description = "A lightweight desktop manager"
 ---

clanModules/zerotier-static-peers/README.md

@@ -1,4 +1,5 @@
-Statically configure the `zerotier` peers of a clan network.
+---
+description = "Statically configure the `zerotier` peers of a clan network."
 ---
 Statically configure the `zerotier` peers of a clan network.
 

clanModules/zt-tcp-relay/README.md

@@ -1,2 +1,3 @@
-Enable ZeroTier VPN over TCP for networks where UDP is blocked.
+---
+description = "Enable ZeroTier VPN over TCP for networks where UDP is blocked."
 ---

docs/mkdocs.yml

@@ -54,7 +54,6 @@ nav:
           - reference/clanModules/borgbackup-static.md
           - reference/clanModules/borgbackup.md
           - reference/clanModules/deltachat.md
-          - reference/clanModules/disk-layouts.md
           - reference/clanModules/ergochat.md
           - reference/clanModules/localbackup.md
           - reference/clanModules/localsend.md

docs/nix/flake-module.nix

@@ -18,8 +18,8 @@
       };
 
       clanModulesFileInfo = pkgs.writeText "info.json" (builtins.toJSON jsonDocs.clanModules);
-      clanModulesReadmes = pkgs.writeText "info.json" (builtins.toJSON jsonDocs.clanModulesReadmes);
+      # clanModulesReadmes = pkgs.writeText "info.json" (builtins.toJSON jsonDocs.clanModulesReadmes);
-      clanModulesMeta = pkgs.writeText "info.json" (builtins.toJSON jsonDocs.clanModulesMeta);
+      # clanModulesMeta = pkgs.writeText "info.json" (builtins.toJSON jsonDocs.clanModulesMeta);
 
       # Simply evaluated options (JSON)
       renderOptions =
@@ -30,6 +30,7 @@
             nativeBuildInputs = [
               pkgs.python3
               pkgs.mypy
+              self'.packages.clan-cli
             ];
           }
           ''
@@ -50,18 +51,25 @@
         sha256 = "sha256-GZMeZFFGvP5GMqqh516mjJKfQaiJ6bL38bSYOXkaohc=";
       };
 
-      module-docs = pkgs.runCommand "rendered" { nativeBuildInputs = [ pkgs.python3 ]; } ''
+      module-docs =
-        export CLAN_CORE=${jsonDocs.clanCore}/share/doc/nixos/options.json
+        pkgs.runCommand "rendered"
-        # A file that contains the links to all clanModule docs
+          {
-        export CLAN_MODULES=${clanModulesFileInfo}
+            nativeBuildInputs = [
-        export CLAN_MODULES_READMES=${clanModulesReadmes}
+              pkgs.python3
-        export CLAN_MODULES_META=${clanModulesMeta}
+              self'.packages.clan-cli
+            ];
+          }
+          ''
+            export CLAN_CORE_PATH=${self}
+            export CLAN_CORE_DOCS=${jsonDocs.clanCore}/share/doc/nixos/options.json
+            # A file that contains the links to all clanModule docs
+            export CLAN_MODULES=${clanModulesFileInfo}
 
-        mkdir $out
+            mkdir $out
 
-        # The python script will place mkDocs files in the output directory
+            # The python script will place mkDocs files in the output directory
-        python3 ${renderOptions}
+            python3 ${renderOptions}
-      '';
+          '';
     in
     {
       devShells.docs = pkgs.callPackage ./shell.nix {

docs/nix/get-module-docs.nix

@@ -3,7 +3,6 @@
   pkgs,
   clanCore,
   clanModules,
-  self,
 }:
 let
   allNixosModules = (import "${nixpkgs}/nixos/modules/module-list.nix") ++ [
@@ -39,20 +38,10 @@ let
     name: module: (evalDocs ((getOptionsWithoutCore [ module ]).clan.${name} or { })).optionsJSON
   ) clanModules;
 
-  clanModulesReadmes = builtins.mapAttrs (
-    module_name: _module: self.lib.modules.getReadme module_name
-  ) clanModules;
-
-  clanModulesMeta = builtins.mapAttrs (
-    module_name: _module:
-    (self.lib.evalClanModules [ module_name ]).config.clan.${module_name}.meta or { }
-  ) clanModules;
-
   # clanCore docs
   clanCoreDocs = (evalDocs (getOptions [ ]).clan.core).optionsJSON;
 in
 {
-  inherit clanModulesReadmes clanModulesMeta;
   clanCore = clanCoreDocs;
   clanModules = clanModulesDocs;
 }

docs/nix/scripts/renderOptions.py

@@ -28,12 +28,12 @@ import os
 from pathlib import Path
 from typing import Any
 
-# Get environment variables
+from clan_cli.api.modules import Frontmatter, extract_frontmatter, get_roles
-CLAN_CORE = os.getenv("CLAN_CORE")
-CLAN_MODULES = os.environ.get("CLAN_MODULES")
-CLAN_MODULES_READMES = os.environ.get("CLAN_MODULES_READMES")
-CLAN_MODULES_META = os.environ.get("CLAN_MODULES_META")
 
+# Get environment variables
+CLAN_CORE_PATH = os.getenv("CLAN_CORE_PATH")
+CLAN_CORE_DOCS = os.getenv("CLAN_CORE_DOCS")
+CLAN_MODULES = os.environ.get("CLAN_MODULES")
 
 OUT = os.environ.get("out")
 
@@ -124,7 +124,7 @@ def render_option(name: str, option: dict[str, Any], level: int = 3) -> str:
 
 
 def module_header(module_name: str) -> str:
-    return f"# {module_name}\n"
+    return f"# {module_name}\n\n"
 
 
 def module_usage(module_name: str) -> str:
@@ -150,9 +150,9 @@ options_head = "\n## Module Options\n"
 
 
 def produce_clan_core_docs() -> None:
-    if not CLAN_CORE:
+    if not CLAN_CORE_DOCS:
         raise ValueError(
-            f"Environment variables are not set correctly: $CLAN_CORE={CLAN_CORE}"
+            f"Environment variables are not set correctly: $CLAN_CORE_DOCS={CLAN_CORE_DOCS}"
         )
 
     if not OUT:
@@ -160,7 +160,7 @@ def produce_clan_core_docs() -> None:
 
     # A mapping of output file to content
     core_outputs: dict[str, str] = {}
-    with open(CLAN_CORE) as f:
+    with open(CLAN_CORE_DOCS) as f:
         options: dict[str, dict[str, Any]] = json.load(f)
         module_name = "clan-core"
         for option_name, info in options.items():
@@ -192,13 +192,11 @@ def produce_clan_core_docs() -> None:
                 of.write(output)
 
 
-def render_meta(meta: dict[str, Any], module_name: str) -> str:
+def render_roles(roles: list[str] | None, module_name: str) -> str:
-    roles = meta.get("availableRoles", None)
-
     if roles:
         roles_list = "\n".join([f"    - `{r}`" for r in roles])
         return f"""
-???+ tip "Inventory (WIP)"
+???+ tip "Inventory usage"
 
     Predefined roles:
 
@@ -226,14 +224,10 @@ def produce_clan_modules_docs() -> None:
         raise ValueError(
             f"Environment variables are not set correctly: $CLAN_MODULES={CLAN_MODULES}"
         )
-    if not CLAN_MODULES_READMES:
-        raise ValueError(
-            f"Environment variables are not set correctly: $CLAN_MODULES_READMES={CLAN_MODULES_READMES}"
-        )
 
-    if not CLAN_MODULES_META:
+    if not CLAN_CORE_PATH:
         raise ValueError(
-            f"Environment variables are not set correctly: $CLAN_MODULES_META={CLAN_MODULES_META}"
+            f"Environment variables are not set correctly: $CLAN_CORE_PATH={CLAN_CORE_PATH}"
         )
 
     if not OUT:
@@ -242,27 +236,36 @@ def produce_clan_modules_docs() -> None:
     with open(CLAN_MODULES) as f:
         links: dict[str, str] = json.load(f)
 
-    with open(CLAN_MODULES_READMES) as readme:
+    # with open(CLAN_MODULES_READMES) as readme:
-        readme_map: dict[str, str] = json.load(readme)
+    #     readme_map: dict[str, str] = json.load(readme)
 
-    with open(CLAN_MODULES_META) as f:
+    # with open(CLAN_MODULES_META) as f:
-        meta_map: dict[str, Any] = json.load(f)
+    #     meta_map: dict[str, Any] = json.load(f)
-        print(meta_map)
+    #     print(meta_map)
 
     # {'borgbackup': '/nix/store/hi17dwgy7963ddd4ijh81fv0c9sbh8sw-options.json', ... }
     for module_name, options_file in links.items():
+        readme_file = Path(CLAN_CORE_PATH) / "clanModules" / module_name / "README.md"
+        print(module_name, readme_file)
+        with open(readme_file) as f:
+            readme = f.read()
+            frontmatter: Frontmatter
+            frontmatter, readme_content = extract_frontmatter(readme, str(readme_file))
+            print(frontmatter, readme_content)
+
         with open(Path(options_file) / "share/doc/nixos/options.json") as f:
             options: dict[str, dict[str, Any]] = json.load(f)
             print(f"Rendering options for {module_name}...")
             output = module_header(module_name)
 
-            if readme_map.get(module_name, None):
+            if frontmatter.description:
-                output += f"{readme_map[module_name]}\n"
+                output += f"**{frontmatter.description}**\n\n"
+            output += f"{readme_content}\n"
 
-            # Add meta information:
+            # get_roles(str) -> list[str] | None
-            # - Inventory implementation status
+            roles = get_roles(str(Path(CLAN_CORE_PATH) / "clanModules" / module_name))
-            if meta_map.get(module_name, None):
+            if roles:
-                output += render_meta(meta_map.get(module_name, {}), module_name)
+                output += render_roles(roles, module_name)
 
             output += module_usage(module_name)
 

flakeModules/clan.nix

@@ -93,6 +93,8 @@ in
           inventory = lib.mkOption { type = lib.types.attrsOf lib.types.unspecified; };
           inventoryFile = lib.mkOption { type = lib.types.unspecified; };
 
+          clanModules = lib.mkOption { type = lib.types.attrsOf lib.types.path; };
+          source = lib.mkOption { type = lib.types.path; };
           meta = lib.mkOption { type = lib.types.attrsOf lib.types.unspecified; };
           all-machines-json = lib.mkOption { type = lib.types.attrsOf lib.types.unspecified; };
           machines = lib.mkOption { type = lib.types.attrsOf (lib.types.attrsOf lib.types.unspecified); };

lib/build-clan/default.nix

@@ -212,6 +212,9 @@ builtins.deepSeq deprecationWarnings {
   inherit nixosConfigurations;
 
   clanInternals = {
+    inherit (clan-core) clanModules;
+    source = "${clan-core}";
+
     meta = mergedInventory.meta;
     inventory = mergedInventory;
 

lib/default.nix

@@ -8,6 +8,7 @@
   evalClanModules = import ./eval-clan-modules { inherit clan-core nixpkgs lib; };
   inventory = import ./inventory { inherit lib clan-core; };
   jsonschema = import ./jsonschema { inherit lib; };
-  modules = import ./description.nix { inherit clan-core lib; };
+  # TODO: migrate to also use toml frontmatter
+  # modules = import ./description.nix { inherit clan-core lib; };
   buildClan = import ./build-clan { inherit clan-core lib nixpkgs; };
 }

lib/description.nix

@@ -1,33 +1,33 @@
-{ lib, clan-core, ... }:
+{ ... }:
 
 rec {
-  getReadme =
+  # getReadme =
-    modulename:
+  #   modulename:
-    let
+  #   let
-      readme = "${clan-core}/clanModules/${modulename}/README.md";
+  #     readme = "${clan-core}/clanModules/${modulename}/README.md";
-      readmeContents =
+  #     readmeContents =
-        if (builtins.pathExists readme) then
+  #       if (builtins.pathExists readme) then
-          (builtins.readFile readme)
+  #         (builtins.readFile readme)
-        else
+  #       else
-          throw "No README.md found for module ${modulename}";
+  #         throw "No README.md found for module ${modulename}";
-    in
+  #   in
-    readmeContents;
+  #   readmeContents;
 
-  getShortDescription =
+  # getShortDescription =
-    modulename:
+  #   modulename:
-    let
+  #   let
-      content = (getReadme modulename);
+  #     content = (getReadme modulename);
-      parts = lib.splitString "---" content;
+  #     parts = lib.splitString "---" content;
-      description = builtins.head parts;
+  #     description = builtins.head parts;
-      number_of_newlines = builtins.length (lib.splitString "\n" description);
+  #     number_of_newlines = builtins.length (lib.splitString "\n" description);
-    in
+  #   in
-    if (builtins.length parts) > 1 then
+  #   if (builtins.length parts) > 1 then
-      if number_of_newlines > 4 then
+  #     if number_of_newlines > 4 then
-        throw "Short description in README.md for module ${modulename} is too long. Max 3 newlines."
+  #       throw "Short description in README.md for module ${modulename} is too long. Max 3 newlines."
-      else if number_of_newlines <= 1 then
+  #     else if number_of_newlines <= 1 then
-        throw "Missing short description in README.md for module ${modulename}."
+  #       throw "Missing short description in README.md for module ${modulename}."
-      else
+  #     else
-        description
+  #       description
-    else
+  #   else
-      throw "Short description delimiter `---` not found in README.md for module ${modulename}";
+  #     throw "Short description delimiter `---` not found in README.md for module ${modulename}";
 }

pkgs/clan-cli/clan_cli/__init__.py

@@ -5,11 +5,12 @@ from pathlib import Path
 from types import ModuleType
 
 # These imports are unused, but necessary for @API.register to run once.
-from clan_cli.api import directory, mdns_discovery
+from clan_cli.api import directory, mdns_discovery, modules
 from clan_cli.arg_actions import AppendOptionAction
 from clan_cli.clan import show
 
-__all__ = ["directory", "mdns_discovery"]
+# API endpoints that are not used in the cli.
+__all__ = ["directory", "mdns_discovery", "modules"]
 
 from . import (
     backups,
@@ -121,6 +122,14 @@ Note: The meta results from clan/meta.json and manual flake arguments. It may no
     )
     show_parser.set_defaults(func=show.show_command)
 
+    modules_parser = subparsers.add_parser("modules", help="Show modules")
+    modules_parser.add_argument(
+        "module_name",
+        help="name of the module",
+        type=str,
+    )
+    modules_parser.set_defaults(func=modules.command)
+
     parser_backups = subparsers.add_parser(
         "backups",
         help="manage backups of clan machines",

pkgs/clan-cli/clan_cli/api/modules.py

@@ -0,0 +1,150 @@
+import argparse
+import json
+import re
+import tomllib
+from dataclasses import dataclass
+from pathlib import Path
+
+from clan_cli.cmd import run_no_stdout
+from clan_cli.errors import ClanCmdError, ClanError
+from clan_cli.nix import nix_eval
+
+from . import API
+
+
+@dataclass
+class Frontmatter:
+    description: str
+    categories: list[str] | None = None
+
+
+def extract_frontmatter(readme_content: str, err_scope: str) -> tuple[Frontmatter, str]:
+    """
+    Extracts TOML frontmatter from a README file content.
+
+    Parameters:
+    - readme_content (str): The content of the README file as a string.
+
+    Returns:
+    - str: The extracted frontmatter as a string.
+    - str: The content of the README file without the frontmatter.
+
+    Raises:
+    - ValueError: If the README does not contain valid frontmatter.
+    """
+    # Pattern to match YAML frontmatter enclosed by triple-dashed lines
+    frontmatter_pattern = r"^---\s+(.*?)\s+---\s?+(.*)$"
+
+    # Search for the frontmatter using the pattern
+    match = re.search(frontmatter_pattern, readme_content, re.DOTALL)
+
+    # If a match is found, return the frontmatter content
+    match = re.search(frontmatter_pattern, readme_content, re.DOTALL)
+
+    # If a match is found, parse the TOML frontmatter and return both parts
+    if match:
+        frontmatter_raw, remaining_content = match.groups()
+        try:
+            # Parse the TOML frontmatter
+            frontmatter_parsed = tomllib.loads(frontmatter_raw)
+        except tomllib.TOMLDecodeError as e:
+            raise ClanError(
+                f"Error parsing TOML frontmatter: {e}",
+                description=f"Invalid TOML frontmatter. {err_scope}",
+                location="extract_frontmatter",
+            )
+
+        return Frontmatter(**frontmatter_parsed), remaining_content
+
+    # If no frontmatter is found, raise an error
+    raise ClanError(
+        "Invalid README: Frontmatter not found.",
+        location="extract_frontmatter",
+        description=f"{err_scope} does not contain valid frontmatter.",
+    )
+
+
+def get_roles(module_path: str) -> None | list[str]:
+    roles_dir = Path(module_path) / "roles"
+    if not roles_dir.exists() or not roles_dir.is_dir():
+        return None
+
+    return [
+        role.stem  # filename without .nix extension
+        for role in roles_dir.iterdir()
+        if role.is_file() and role.suffix == ".nix"
+    ]
+
+
+@dataclass
+class ModuleInfo:
+    description: str
+    categories: list[str] | None
+    roles: list[str] | None
+
+
+def get_modules(base_path: str) -> dict[str, str]:
+    cmd = nix_eval(
+        [
+            f"{base_path}#clanInternals.clanModules",
+            "--json",
+        ]
+    )
+    try:
+        proc = run_no_stdout(cmd)
+        res = proc.stdout.strip()
+    except ClanCmdError:
+        raise ClanError(
+            "clanInternals might not have clanModules attributes",
+            location=f"list_modules {base_path}",
+            description="Evaluation failed on clanInternals.clanModules attribute",
+        )
+    modules: dict[str, str] = json.loads(res)
+    return modules
+
+
+@API.register
+def list_modules(base_path: str) -> list[str]:
+    """
+    Show information about a module
+    """
+    modules = get_modules(base_path)
+    return [m for m in modules.keys()]
+
+
+@API.register
+def show_module_info(base_path: str, module_name: str) -> ModuleInfo:
+    """
+    Show information about a module
+    """
+    modules = get_modules(base_path)
+    module_path = modules.get(module_name, None)
+    if not module_path:
+        raise ClanError(
+            "Module not found",
+            location=f"show_module_info {module_name}",
+            description="Module does not exist",
+        )
+    module_readme = Path(module_path) / "README.md"
+    if not module_readme.exists():
+        raise ClanError(
+            "Module not found",
+            location=f"show_module_info {module_name}",
+            description="Module does not exist or doesn't have any README.md file",
+        )
+    with open(module_readme) as f:
+        readme = f.read()
+        frontmatter, readme_content = extract_frontmatter(
+            readme, f"{module_path}/README.md"
+        )
+
+    return ModuleInfo(
+        description=frontmatter.description,
+        categories=frontmatter.categories,
+        roles=get_roles(module_path),
+    )
+
+
+def command(args: argparse.Namespace) -> None:
+    res = show_module_info(args.flake, args.module_name)
+    print(res)