Made targets work with a json

.env.example

@@ -4,3 +4,7 @@ DISCORD_TOKEN=
 # Optional tuning
 CHECK_INTERVAL=60
 CHECK_TIMEOUT=10
+
+# Targets file (hot-loaded each scan) and its auto-maintained last-good copy
+# TARGETS_FILE=targets.json
+# TARGETS_BACKUP_FILE=targets.json.bak

.gitignore

@@ -3,3 +3,4 @@ venv/
 __pycache__/
 *.pyc
 .status_message.json
+targets.json.bak

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

config.py

@@ -10,3 +10,6 @@ CHECK_INTERVAL = int(os.getenv('CHECK_INTERVAL', '60'))
 CHECK_TIMEOUT = float(os.getenv('CHECK_TIMEOUT', '10'))
 
 STATE_FILE = os.getenv('STATE_FILE', '.status_message.json')
+
+TARGETS_FILE = os.getenv('TARGETS_FILE', 'targets.json')
+TARGETS_BACKUP_FILE = os.getenv('TARGETS_BACKUP_FILE', 'targets.json.bak')

main.py

@@ -77,7 +77,7 @@ class HealthBot(discord.Client):
         session = await self._ensure_session()
         return await checks.run_checks(session, config.CHECK_TIMEOUT)
 
-    def build_embed(self, results):
+    def build_embed(self, results, using_backup=False):
         color = _health_color(results)
         embed = discord.Embed(
             title='Service Health',
@@ -115,14 +115,20 @@ class HealthBot(discord.Client):
                 lines.append(f'**DNS resolution ({label})** {val}')
 
             embed.add_field(name=r['name'], value='\n'.join(lines), inline=False)
-        embed.set_footer(text=f'Updates every {config.CHECK_INTERVAL}s')
+        embed.set_footer(text=self._footer_text(using_backup))
         return embed
 
+    def _footer_text(self, using_backup):
+        text = f'Updates every {config.CHECK_INTERVAL}s'
+        if using_backup:
+            text += ' · ⚠ targets.json invalid — using last known-good config'
+        return text
+
     async def update_embeds(self):
         if not self.status_messages:
             return
-        results = await self.run_checks()
-        embed = self.build_embed(results)
+        results, using_backup = await self.run_checks()
+        embed = self.build_embed(results, using_backup)
 
         kept = []
         for entry in self.status_messages:
@@ -172,8 +178,14 @@ bot = HealthBot()
 @bot.tree.command(name='status', description='Post a live-updating health embed for the services')
 async def status(interaction: discord.Interaction):
     await interaction.response.defer()
-    results = await bot.run_checks()
-    embed = bot.build_embed(results)
+    try:
+        results, using_backup = await bot.run_checks()
+    except checks.TargetsConfigError as exc:
+        await interaction.followup.send(
+            f'Could not load targets config: {exc}', ephemeral=True,
+        )
+        return
+    embed = bot.build_embed(results, using_backup)
 
     existing = next(
         (m for m in bot.status_messages if m['channel_id'] == interaction.channel_id),

targets.json

@@ -0,0 +1,21 @@
+[
+  {
+    "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
+  }
+]