Made targets work with a json

checks.py

@@ -1,32 +1,16 @@
 import asyncio
 import json
+import logging
+import shutil
 import time
 from urllib.parse import urlparse
 
 import aiohttp
 from mcstatus import JavaServer
 
-TARGETS = [
-    {
-        'name': 'Gitea',
-        'url': 'https://gitea.rainbow-herring.ts.net/api/healthz',
-        'kind': 'gitea',
-        'critical': True,
-    },
-    {
-        'name': 'Packs Site (Production)',
-        'url': 'https://jakerasp.rainbow-herring.ts.net/healthz/',
-        'kind': 'packs',
-        'critical': True,
-    },
-    {
-        'name': 'Minecraft Server',
-        'host': 'jakelaptop.rainbow-herring.ts.net',
-        'port': 10000,
-        'kind': 'minecraft',
-        'critical': True,
-    },
-]
+import config
+
+log = logging.getLogger('healthbot')
 
 GITEA_VERSION_URL = 'https://gitea.rainbow-herring.ts.net/api/v1/version'
 
@@ -36,6 +20,75 @@ DOH_RESOLVERS = {
 }
 
 
+class TargetsConfigError(Exception):
+    """Raised when the targets configuration file is missing or invalid."""
+
+
+def validate_targets(data):
+    """Validate parsed targets data, returning a normalized list of targets."""
+    if not isinstance(data, list):
+        raise TargetsConfigError('targets must be a JSON list')
+    targets = []
+    for i, entry in enumerate(data):
+        if not isinstance(entry, dict):
+            raise TargetsConfigError(f'entry {i} is not an object')
+        name = entry.get('name')
+        if not isinstance(name, str) or not name.strip():
+            raise TargetsConfigError(f'entry {i} missing a valid "name"')
+        kind = entry.get('kind')
+        if not isinstance(kind, str) or not kind.strip():
+            raise TargetsConfigError(f'entry {i} missing a valid "kind"')
+        if kind == 'minecraft':
+            host = entry.get('host')
+            port = entry.get('port')
+            if not isinstance(host, str) or not host.strip():
+                raise TargetsConfigError(f'entry {i} missing a valid "host"')
+            if not isinstance(port, int) or not (0 < port < 65536):
+                raise TargetsConfigError(f'entry {i} missing a valid "port"')
+        else:
+            url = entry.get('url')
+            if not isinstance(url, str) or not url.strip():
+                raise TargetsConfigError(f'entry {i} missing a valid "url"')
+        critical = entry.get('critical', True)
+        if not isinstance(critical, bool):
+            raise TargetsConfigError(f'entry {i} "critical" must be true/false')
+        target = {'name': name.strip(), 'kind': kind.strip(), 'critical': critical}
+        target.update({k: entry[k] for k in ('url', 'host', 'port') if k in entry})
+        targets.append(target)
+    return targets
+
+
+def load_targets():
+    """Load the live targets file; on success refresh the backup copy.
+
+    Raises TargetsConfigError if the live file is missing or invalid.
+    """
+    try:
+        with open(config.TARGETS_FILE, 'r') as f:
+            raw = f.read()
+        targets = validate_targets(json.loads(raw))
+    except (OSError, ValueError, TargetsConfigError) as exc:
+        raise TargetsConfigError(
+            f'invalid targets file {config.TARGETS_FILE}: {exc}'
+        ) from exc
+    try:
+        shutil.copyfile(config.TARGETS_FILE, config.TARGETS_BACKUP_FILE)
+    except OSError as exc:
+        log.warning('Could not back up targets file: %s', exc)
+    return targets
+
+
+def load_backup_targets():
+    """Load the last known-good copy of the targets file."""
+    try:
+        with open(config.TARGETS_BACKUP_FILE, 'r') as f:
+            return validate_targets(json.load(f))
+    except (OSError, ValueError, TargetsConfigError) as exc:
+        raise TargetsConfigError(
+            f'backup targets file {config.TARGETS_BACKUP_FILE} also invalid: {exc}'
+        ) from exc
+
+
 async def _get(session, url, timeout):
     started = time.monotonic()
     async with session.get(
@@ -179,7 +232,14 @@ async def check_target(session, target, timeout):
 
 
 async def run_checks(session, timeout):
+    using_backup = False
+    try:
+        targets = load_targets()
+    except TargetsConfigError as exc:
+        log.exception('Targets config problem: %s', exc)
+        targets = load_backup_targets()
+        using_backup = True
     results = await asyncio.gather(
-        *(check_target(session, target, timeout) for target in TARGETS)
+        *(check_target(session, target, timeout) for target in targets)
     )
-    return list(results)
+    return list(results), using_backup