Log format

Changes
* Added documentation
* More types
* Argparse command-line interface
* A '--dry-run' option

Tests
* Passes mypy
* Build with nix

README.md

@@ -1,19 +1,23 @@
 # Dyn-Gandi
+
 A DNS record updater for [Gandi's LiveDNS](https://api.gandi.net/docs/livedns/) API.
 This script is heavily inspired by [dyn-gandi](https://github.com/Danamir/dyn-gandi).
 
 ## How it works
+
 This script determines the the current IP address by querying the resolvers defined in the config file.
 It then queries the subdomains' A records off of Gandi and compares their IP addresses to the current IP address.
 Should the IP address of a subdomain's A record not match your current IP address it will be updated. The subdomain's A record will be created should it not already exist.
 
 ## Notes
+
 Every invocation of the script causes at least 1 request to a resolver specified and 1 API call to Gandi per domain.
 Updating a subdomain's A record is 1 API request per subdomain, even if they share the same domain.  
 Resolvers are queried in the order specified until one returns a valid IP address.  
 It is also possible to define a path to a file with the API key written in it. This is good for environments where the config file has to be shared like in a nix project.
 
-## How to use
+## Usage
+
 First, get your API key from https://account.gandi.net/en/users/USER/security where `USER` is your Gandi username.
 
 The script looks for a config file at `$HOME/.config/dyn-gandi/config.log` or `/etc/dyn-gandi.conf` in that order. So create a file at one of these locations according to the schema below.
@@ -40,9 +44,10 @@ The script looks for a config file at `$HOME/.config/dyn-gandi/config.log` or `/
 ```
 
 ## Nix
-Add this to the modules.
-```nix
 
+Add this to the modules.
+
+```nix
 inputs = {
   nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
   dyn-gandi.url = "git+https://git.krsnik.at/Kristian/dyn-gandi";
@@ -78,6 +83,7 @@ outputs = {
   ...
 }
 ```
+
 Use `dyn-gandi.nixosModules.default` for a NixOs module and `dyn-gandi.homeManagerModules.default` for home-manager
 
 `dyn-gandi.timer` specifies a timer in seconds when the script should be repeated.

dyn_gandi/main.py

@@ -1,12 +1,21 @@
-import requests
-import json
-import re
 import os
+import re
+import json
+import argparse
 from datetime import datetime
 from typing import Callable, Any
 
+import requests
+
 
 def loadSettings(path: str | None) -> dict:
+    '''
+        Load the settings file.
+
+        `path` Path to a settings file.
+        By default the program will look for `$HOME/dyn-gandi/config.json` and then `/etc/dyn-gandi.json`.
+    '''
+
     if path is None:
         path = f"{os.path.expanduser('~')}/.config/dyn-gandi/config.json"
 
@@ -14,14 +23,21 @@ def loadSettings(path: str | None) -> dict:
             path = '/etc/dyn-gandi.json'
 
     if not os.path.exists(path):
+        print(f"[ERROR] '{path}' does not exist.")
         quit()
 
-    # TODO: check integrity of the config file
+    # TODO check integrity of the config file
     with open(path, 'r') as file:
-        # Read if the API keys are path to files
+        # Load as dictionary
         config = json.load(file)
+
+        # API Key entries
         keys = config['api'].keys()
+
+        # This will build up a copy of the API section with the API keys instead of filenames.
         mask = dict()
+
+        # If the API key is a file the use the contents as a new key.
         for key in keys:
             api_key = key
             if os.path.exists(key):
@@ -30,25 +46,49 @@ def loadSettings(path: str | None) -> dict:
             mask[key] = api_key
         config['api'] = {mask[key]: value for key,
                          value in config['api'].items()}
+
     return config
 
 
-def log(logline: str, path: str = './log.txt') -> None:
-    # Appends logline at the end of the file file with a timestamp
-    with open(path, 'a') as file:
-        file.write(
-            f"[{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}]{logline}\n")
+def log(logline: str, path: str = './log.txt', stdout: bool = False) -> None:
+    '''
+        Appends logline at the end of the file file with a timestamp
+
+        `logline` The line to log.
+
+        'path' Path to file where to log.
+
+        `stdout` Wether to print to stdout instead of a file.
+    '''
+
+    line = f"[{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}]{logline}"
+
+    if stdout:
+        print(line)
+    else:
+        with open(path, 'a') as file:
+            file.write(line + '\n')
 
 
 def getCurrentIP(resolvers: list[str], log: Callable[[str], Any]) -> str | None:
-    # Go through resolvers until one retuns an IP
+    '''
+        Go through resolvers until one returns an IP.
+
+        `resolvers` A list of IP resolvers.
+
+        `log` A function which takes a string and logs it.
+    '''
+
     for resolver in resolvers:
         response = requests.get(resolver)
-        if response.status_code == 200:
+
+        if response.ok:
             current_ip = response.text.strip()
-            # it suffices to check whether the search is not None since the regex is matches from beginning to end
+
+            # It suffices to check whether the search is not None since the regex matches from beginning to end.
             is_ipv4 = re.search(
                 '^((25[0-5]|(2[0-4]|1\d|[1-9]|)\d)\.?\\b){4}$', current_ip) is not None
+
             if is_ipv4:
                 log(f"[OK][{resolver}] Current IP: '{current_ip}'")
                 return current_ip  # Break if we have found our IP
@@ -56,37 +96,65 @@ def getCurrentIP(resolvers: list[str], log: Callable[[str], Any]) -> str | None:
                 log(f"[ERROR][{resolver}] '{current_ip}' is not IPv4")
         else:
             log(f"[ERROR][{resolver}][{response.status_code}] {response.text}")
+
     return None
 
 
 def checkRecords(api: dict[str, dict[str, list[str]]], current_ip: str, log: Callable[[str], Any]) -> dict[str, dict[str, list[str]]]:
-    # Returns the records that need to be renewed
-    # TODO: Also detect TTL change
+    '''
+        Return records that need to be renewed.
+
+        `api` The API section of the settings file.
+
+        `current_ip` The current IP address.
+
+        `log` A function that takes in a string and logs it.
+    '''
+
+    # TODO: Detect TTL change
+
     records_to_renew = api
     for key, domains in api.items():
         headers = {'authorization': f"Apikey {key}"}
+
         for domain, _ in domains.items():
             response = requests.get(
                 f"https://api.gandi.net/v5/livedns/domains/{domain}/records?rrset_type=A", headers=headers)
+
             if response.status_code == 200:
-                records_to_renew[key][domain] = list(
-                    set(records_to_renew[key][domain]) - set(record['rrset_name'] for record in (filter(lambda x: current_ip in x['rrset_values'], response.json()))))
+                records_to_renew[key][domain] = list(set(records_to_renew[key][domain]) - set(record['rrset_name'] for record in (
+                    filter(lambda x: current_ip in x['rrset_values'], response.json()))))
+
+                if records_to_renew[key][domain] != []:
+                    log(f"[INFO][{','.join(records_to_renew)}] Record need to be renewed")
+
             else:
                 log(f"[ERROR][{domain}][{response.status_code}] {response.json()}")
 
     return records_to_renew
 
 
-def renewRecords(api: dict[str, dict[str, list[str]]], current_ip: str, log: Callable[[str], Any], ttl) -> None:
-    # Updates the records and reates them if they don't exist
+def renewRecords(api: dict[str, dict[str, list[str]]], current_ip: str, log: Callable[[str], Any], ttl: int = 300) -> None:
+    '''
+        Update records and create them, if they don't exist.
+
+        `api` The API section of the settings file.
+
+        `current_ip` The current IP address.
+
+        `log` A function that takes a string and logs it.
+
+        `ttl` How long a record should be cached.
+    '''
+
     payload = json.dumps({
         'rrset_values': [current_ip],
         'rrset_ttl': ttl
     })
 
-    for key, domains in api.items():
+    for api_key, domains in api.items():
         headers = {
-            'authorization': f"Apikey {key}",
+            'authorization': f"Apikey {api_key}",
             'content-type': 'application/json',
         }
 
@@ -100,36 +168,40 @@ def renewRecords(api: dict[str, dict[str, list[str]]], current_ip: str, log: Cal
                     log(f"[ERROR][{domain}][{record}][{response.status_code}] {response.json()}")
 
 
-def parseArgv(argv: list[str]) -> dict[str, list[str]]:
-    cli_options: dict = {}
-    buffer: str = ''
+def parseArgs(args: list[str]) -> argparse.Namespace:
+    '''
+        Parse command-line arguments.
+
+        `args` A list of user-supplied command line arguments.
+    '''
+
+    parser = argparse.ArgumentParser(
+        description='A program that renews A records via the Gandi API v5.')
+
+    parser.add_argument('--config', type=str, default=None,
+                        help='Path to a config file.')
+    parser.add_argument('--dry-run', action='store_true',
+                        help='Just perform a dry-run.')
+
+    return parser.parse_args(args)
 
-    for arg in argv:
-        if arg.startswith('--'):
-            cli_options[arg.removeprefix('--')] = []
-            buffer = arg.removeprefix('--')
-        else:
-            cli_options[buffer].append(arg)
-    return cli_options
 
 def main():
-    argv = os.sys.argv
-    options = {}
-    if len(argv) > 1:
-        options = parseArgv(argv[1:])
+    # Parse user-supplied command-line arguments.
+    args = parseArgs(os.sys.argv[1:])
 
-    config_path = None
-    if 'config' in options:
-        config_path = options['config'][0]
+    # Read in the settings file.
+    config = loadSettings(args.config)
 
-    settings = loadSettings(config_path)
-    log_path, ttl = settings['log_path'], settings['ttl']
-    def logger(x: str) -> Any: return log(x, log_path)
+    def logger(x: str) -> Any: return log(x, config['log_path'], args.dry_run)
 
-    current_ip = getCurrentIP(settings['resolvers'], logger)
+    current_ip = getCurrentIP(config['resolvers'], logger)
     if current_ip is not None:
-        records_to_renew = checkRecords(settings['api'], current_ip, logger)
-        renewRecords(records_to_renew, current_ip, logger, ttl=ttl)
+        records_to_renew = checkRecords(config['api'], current_ip, logger)
+
+        # Do not perform an actual record change during a dry-run.
+        if not args.dry_run:
+            renewRecords(records_to_renew, current_ip, logger, config['ttl'])
 
 
 if __name__ == '__main__':

flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "A very basic flake";
+  description = "A program to update an A record with the Gandi API v5.";
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-23.05";
@@ -13,15 +13,23 @@
     forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
     pkgs = forAllSystems (system: nixpkgs.legacyPackages.${system});
   in {
-    # Formatter
+    # `nix fmt`
     formatter = forAllSystems (system: nixpkgs.legacyPackages.${system}.alejandra);
 
-    # Packages
+    # `nix build`
     packages = forAllSystems (system: {
       default = pkgs.${system}.poetry2nix.mkPoetryApplication {projectDir = self;};
     });
 
-    # Dev Shell
+    # `nix run`
+    apps = forAllSystems (system: {
+      default = {
+        program = "${self.packages.${system}.default}/bin/dyn_gandi";
+        type = "app";
+      };
+    });
+
+    # `nix develop`
     devShells = forAllSystems (system: {
       default = pkgs.${system}.mkShellNoCC {
         packages = with pkgs.${system}; [
@@ -33,16 +41,9 @@
       };
     });
 
-    # Run as apps
-    apps = forAllSystems (system: {
-      default = {
-        program = "${self.packages.${system}.default}/bin/dyn_gandi";
-        type = "app";
-      };
-    });
+    # TODO Home Manager Module
+    # homeManagerModules.default = import ./nix/hm-module.nix self;
 
-    # Home Manager Module
-    homeManagerModules.default = import ./nix/hm-module.nix self;
     # NixOS Module
     nixosModules.default = import ./nix/module.nix inputs;
   };