3 files changed, 195 insertions, 66 deletions

diff --git a/pre-commit.sh b/pre-commit.sh
new file mode 100755
index 0000000..941879e
--- /dev/null
+++ b/pre-commit.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+pylint simpleddns.py || exit 1
+mypy --strict simpleddns.py || exit 1
diff --git a/pylintrc.toml b/pylintrc.toml
index 39bb057..e111d72 100644
--- a/pylintrc.toml
+++ b/pylintrc.toml
@@ -389,7 +389,7 @@ timeout-methods = ["requests.api.delete", "requests.api.get", "requests.api.head
 
 [tool.pylint.miscellaneous]
 # List of note tags to take in consideration, separated by a comma.
-notes = ["FIXME", "XXX", "TODO"]
+notes = []
 
 # Regular expression of note tags to take in consideration.
 # notes-rgx =
diff --git a/simpleddns.py b/simpleddns.py
index 45d9e89..45e8308 100755
--- a/simpleddns.py
+++ b/simpleddns.py
@@ -6,10 +6,12 @@ import sys
 import subprocess
 import argparse
 import ast
+import dataclasses
+from time import sleep
 from abc import ABC, abstractmethod
-from typing import NoReturn, Optional
+from typing import NoReturn, Optional, Any
 from pathlib import Path
-# import requests
+import requests
 
 def parse_args() -> argparse.Namespace:
 	'''Parse command-line arguments'''
@@ -20,25 +22,16 @@ def parse_args() -> argparse.Namespace:
 	parser.add_argument('--setup', help='Set up configuration', action='store_true')
 	return parser.parse_args()
 
-args = parse_args()
-
-simpleddns_config_dir = os.getenv('SIMPLEDDNS_CONFIG_DIR')
-xdg_config_dir = os.getenv('XDG_CONFIG_DIR')
-if simpleddns_config_dir:
-	config_dir = Path(simpleddns_config_dir)
-elif xdg_config_dir:
-	config_dir = Path(xdg_config_dir, 'simpleddns')
-else:
-	config_dir = Path('~/.config/simpleddns').expanduser()
-os.makedirs(config_dir, exist_ok = True)
-config_path = Path(config_dir, 'config')
-
 def fatal_error(message: str) -> NoReturn:
 	'''Output error message & exit'''
 	sys.stderr.write(f'Fatal error: {message}\n')
 	sys.exit(1)
 
-def setup_config() -> None:
+def warn(message: str) -> None:
+	'''Print warning message'''
+	sys.stderr.write(f'WARNING: {message}\n')
+
+def setup_config(config_path: Path) -> None:
 	'''Interactively set up configuration file'''
 	if config_path.exists():
 		should_delete = input('Configuration already exists. Delete it [y/n]? ')
@@ -60,73 +53,170 @@ def setup_config() -> None:
 	domain_type = input('Select a domain type from the list above [1-1]: ').strip()
 	if domain_type == '1':
 		access_token = input('Enter personal access token: ')
-		options = f'access_token = {repr(access_token)}'
+		options = f'''# Personal access token (secret!!)
+    access_token = {repr(access_token)}'''
 		type_name = 'linode'
 	else:
 		print('Invalid choice')
 		return
 	fd = os.open(config_path, os.O_CREAT | os.O_WRONLY | os.O_EXCL, 0o600)
 	with os.fdopen(fd, 'w') as config:
-		config.write(f'''Domain {type_name} {domain_name}
-    getip = {repr(get_ip)}
+		config.write(f'''Settings
+    # Interval in seconds between checking IP address for changes
+    #  (API calls are only made when it changes)
+    interval = 15
+    # Timeout to wait for API responses
+    timeout = 20
+Domain {type_name} {domain_name}
+    # Command(s) for getting IP address(es)
+    getip = [{repr(get_ip)}]
     {options}
 ''')
-if args.setup:
-	setup_config()
-	sys.exit(0)
+	print(f'Configuration created successfully at {config_path}')
 
-if not config_path.exists():
-	fatal_error("Configuration doesn't exist. Try running with --setup first.")
-if os.name == 'posix':
-	config_mode = config_path.stat().st_mode
-	if config_mode & 0o4:
-		fatal_error(f'''DANGER: configuration file {config_path} allows
-reading by other users (mode {config_mode & 0o777:o}).
-If there are API tokens in there, revoke them immediately!!''')
+@dataclasses.dataclass
+class Settings:
+	'''Global (i.e. not per-domain) settings'''
+	interval: int = 15
+	timeout: int = 20
 
 class Domain(ABC):
 	'''A domain whose DNS will be updated'''
-	domain: str
-	getip: str
-	def __init__(self, domain: str):
-		self.domain = domain
+	full_domain: str
+	root_domain: str
+	subdomain: str
+	getip: list[str]
+	settings: Settings
+	last_ips: list[str]
+	def __init__(self, settings: Settings, domain: str):
+		self.settings = settings
+		self.full_domain = domain
+		last_dot = domain.rfind('.')
+		if last_dot == -1:
+			raise ValueError(f'Domain {domain} has no . in it')
+		second_last_dot = domain.rfind('.', 0, last_dot)
+		if second_last_dot == -1:
+			self.subdomain = ''
+			self.root_domain = domain
+		else:
+			self.subdomain = domain[:second_last_dot]
+			self.root_domain = domain[second_last_dot+1:]
+		self.last_ips = []
+		self._init()
+	@abstractmethod
+	def _init(self) -> None:
+		'''Extra provider-specific initialization'''
 	@abstractmethod
-	def update(self, ip: str) -> None:
-		'''Make necessary API request to update domain to use new IP address'''
+	def update(self, ips: list[str]) -> bool:
+		'''Make necessary API request to update domain to use new IP addresses.
+		   Returns False on failure.'''
 	@abstractmethod
 	def validate_specifics(self) -> str:
-		'''Validate details specific to subclass'''
+		'''Validate provider-specific settings for domain'''
 	def validate(self) -> str:
-		'''Validate this object (ensure all required fields are set)'''
+		'''Validate this object (ensure all required settings are set)'''
 		if not getattr(self, 'getip', ''):
 			return 'getip not set'
+		if not isinstance(self.getip, list):
+			return 'getip should be a list.'
 		return self.validate_specifics()
-	def get_ip(self) -> Optional[str]:
-		'''Get IP address using the registered command.'''
-		result = subprocess.run(self.getip, shell=True, stdout=subprocess.PIPE, check=False)
-		if result.returncode:
-			print(f'WARNING: {self.getip} failed (exit code {result.returncode})')
-			return None
-		return result.stdout.decode(errors='replace').strip()
+	def get_ips(self) -> list[str]:
+		'''Get IP addresses using the registered commands.'''
+		ips = []
+		for cmd in self.getip:
+			result = subprocess.run(cmd, shell=True, stdout=subprocess.PIPE, check=False)
+			if result.returncode:
+				warn(f'{self.getip} failed (exit code {result.returncode})')
+				return []
+			ip = result.stdout.decode(errors='replace').strip()
+			# this test isn't perfect, but it should catch most cases of weird stuff
+			if not ip or '..' in ip or any(c not in '0123456789abcdefABCDEF:.' for c in ip):
+				warn(f'IP address {repr(ip)} is invalid')
+				return []
+			ips.append(ip)
+		ips.sort()
+		return ips
+	def check_for_update(self) -> None:
+		'''Update DNS records if IP has changed'''
+		ips = self.get_ips()
+		if ips == self.last_ips:
+			return
+		if self.update(ips):
+			self.last_ips = ips
 
 class LinodeDomain(Domain):
 	'''Domain registered with Linode Domains'''
 	access_token: str
+	_error: bool
+	# Domain ID for Linode API
+	_id: Optional[int]
+	def _init(self) -> None:
+		self._id = None
 	def __repr__(self) -> str:
-		return f'<LinodeDomain domain={self.domain} ' \
+		return f'<LinodeDomain domain={self.full_domain} ' \
 			'getip={repr(self.getip)} ' \
 			'access_token={repr(self.access_token)}>'
-	def update(self, ip: str) -> None:
-		print(f'update IP: {ip}')
+	def _headers(self, method: str = 'GET') -> dict[str, str]:
+		'''Get HTTP headers for making requests'''
+		headers = {'Accept': 'application/json', 'Authorization': f'Bearer {self.access_token}'}
+		if method in ['POST', 'PUT']:
+			headers['Content-Type'] = 'application/json'
+		return headers
+	def _paginated_get(self, url: str) -> list[Any]:
+		'''Get results for a Linode paginated GET API endpoint.'''
+		headers = self._headers()
+		results = []
+		page_size = 500
+		for page in range(1,100):
+			page_url = f'{url}{"&" if "?" in url else "?"}page={page}&page_size={page_size}'
+			try:
+				response = requests.get(page_url, headers=headers, timeout=self.settings.timeout)
+			except requests.RequestException as e:
+				warn(f'Error making request to {url}: {e}')
+			sleep(0.33) # should prevent us from hitting Linode's rate limit
+			try:
+				response_json = response.json()
+				response_data = response_json['data']
+				if not isinstance(response_data, list):
+					raise ValueError('"data" member is not a list')
+			except (requests.JSONDecodeError, KeyError, ValueError) as e:
+				warn(f'Invalid JSON at endpoint {repr(page_url)}: {e}')
+				break
+			results.extend(response_data)
+			if len(response_data) < page_size:
+				# Reached last page, presumably
+				break
+			if page == 99:
+				warn(f'Giving up after 99 pages of responses to API endpoint {repr(url)}')
+		return results
+	def update(self, ips: list[str]) -> bool:
+		self._error = False
+		if self._id is None:
+			domains = self._paginated_get('https://api.linode.com/v4/domains')
+			if self._error:
+				return False
+			for domain in domains:
+				domain_name = domain['domain']
+				if self.root_domain == domain_name:
+					# this is it!
+					self._id = domain['id']
+			if self._id is None:
+				warn(f'Domain {self.root_domain} not found in Linode. Are you sure it is set up there?')
+				return False
+		records = self._paginated_get(f'https://api.linode.com/v4/domains/{self._id}/records')
+		print(records)
+		print(self.subdomain)
+		return not self._error
 	def validate_specifics(self) -> str:
 		if not getattr(self, 'access_token', ''):
 			return 'Access token not set'
 		# OK
 		return ''
 
-def parse_config() -> list[Domain]:
+def parse_config(config_path: Path) -> tuple[Settings, list[Domain]]:
 	'''Parse configuration file'''
-	curr_domain = None
+	curr_section: Settings | Domain | None = None
+	settings = Settings()
 	domains: list[Domain] = []
 	with open(config_path, encoding='utf-8') as config:
 		for line in config:
@@ -134,9 +224,13 @@ def parse_config() -> list[Domain]:
 			if line[0] == '#':
 				# comment
 				continue
-			if line.startswith('Domain '):
-				if curr_domain:
-					domains.append(curr_domain)
+			if line.startswith('Settings'):
+				if isinstance(curr_section, Domain):
+					domains.append(curr_section)
+				curr_section = settings
+			elif line.startswith('Domain '):
+				if isinstance(curr_section, Domain):
+					domains.append(curr_section)
 				parts = line.split()
 				if len(parts) != 3:
 					fatal_error('Domain declaration should have exactly ' \
@@ -144,26 +238,58 @@ def parse_config() -> list[Domain]:
 				kind = parts[1]
 				domain_name = parts[2]
 				if kind == 'linode':
-					curr_domain = LinodeDomain(domain_name)
+					curr_section = LinodeDomain(settings, domain_name)
 				else:
 					fatal_error(f'No such domain type: {kind}')
 			else:
-				if not curr_domain:
-					fatal_error('First non-empty line of configuration must be a Domain declaration')
+				if not curr_section:
+					fatal_error('First non-empty line of configuration must be a Domain declaration or Settings')
 				parts = [part.strip() for part in line.split('=', maxsplit=1)]
 				if len(parts) != 2:
 					fatal_error(f'Invalid syntax (want key = value): {line}')
 				[key, value] = parts
-				setattr(curr_domain, key, ast.literal_eval(value))
-	if curr_domain:
-		domains.append(curr_domain)
+				setattr(curr_section, key, ast.literal_eval(value))
+	if isinstance(curr_section, Domain):
+		domains.append(curr_section)
 	for domain in domains:
 		err = domain.validate()
 		if err:
-			fatal_error(f'In domain {domain.domain}: {err}')
-	return domains
+			fatal_error(f'In domain {domain.full_domain}: {err}')
+	return (settings, domains)
+
+def main() -> None:
+	'''Run simpleddns'''
+	args = parse_args()
+	simpleddns_config_dir = os.getenv('SIMPLEDDNS_CONFIG_DIR')
+	xdg_config_dir = os.getenv('XDG_CONFIG_DIR')
+	if simpleddns_config_dir:
+		config_dir = Path(simpleddns_config_dir)
+	elif xdg_config_dir:
+		config_dir = Path(xdg_config_dir, 'simpleddns')
+	else:
+		config_dir = Path('~/.config/simpleddns').expanduser()
+	os.makedirs(config_dir, exist_ok = True)
+	config_path = Path(config_dir, 'config')
+	if args.setup:
+		setup_config(config_path)
+		sys.exit(0)
+	if not config_path.exists():
+		fatal_error("Configuration doesn't exist. Try running with --setup first.")
+	if os.name == 'posix':
+		config_mode = config_path.stat().st_mode
+		if config_mode & 0o4:
+			fatal_error(f'''DANGER: configuration file {config_path} allows
+	reading by other users (mode {config_mode & 0o777:o}).
+	If there are API tokens in there, revoke them immediately!!''')
+
+	settings, domains = parse_config(config_path)
+	if not domains:
+		fatal_error('No domains defined. Try running with --setup?')
+	while True:
+		print('Checking...')
+		for domain in domains:
+			domain.check_for_update()
+		sleep(settings.interval)
 
-configured_domains = parse_config()
-if not configured_domains:
-	fatal_error('No domains defined. Try running with --setup?')
-print(configured_domains[0].get_ip())
+if __name__ == '__main__':
+	main()