Expand ecash explorer capabilities

Add Fedimint discovery, dual SQLite/Postgres storage, richer review handling, and generated social imagery.

api/src/index.ts

@@ -17,17 +17,30 @@ function track<T>(work: Promise<T>): Promise<T> {
   return work;
 }
 
+/*
+ * One cycle of each kind at a time. A cycle that outlives its interval (a relay socket
+ * that never closes, a wedged fetch) must not have the next timer tick start a second
+ * copy beside it — that doubles the relay load and interleaves state writes for no
+ * new information. The late cycle finishes; the ticks it swallowed are simply skipped.
+ */
+let probeRunning = false;
+let discoveryRunning = false;
+
 async function probeCycle(): Promise<void> {
-  if (shuttingDown) return;
+  if (shuttingDown || probeRunning) return;
+  probeRunning = true;
   try {
     await track(probeAll());
   } catch (err) {
     log.error('probe cycle failed', { reason: err instanceof Error ? err.message : String(err) });
+  } finally {
+    probeRunning = false;
   }
 }
 
 async function discoveryCycle(backfill: boolean): Promise<void> {
-  if (shuttingDown) return;
+  if (shuttingDown || discoveryRunning) return;
+  discoveryRunning = true;
   try {
     const result = await track(runDiscovery(backfill));
     // New mints are probed straight away, not on the next cycle, so their page has
@@ -37,16 +50,20 @@ async function discoveryCycle(backfill: boolean): Promise<void> {
     log.error('discovery cycle failed', {
       reason: err instanceof Error ? err.message : String(err),
     });
+  } finally {
+    discoveryRunning = false;
   }
 }
 
-function main(): void {
-  getDb();
+async function main(): Promise<void> {
+  // Fail loudly here rather than on the first request: a bad DATABASE_URL, an
+  // unreachable Postgres or an unwritable SQLite directory should stop the boot.
+  await getDb();
 
   const server = serve({ fetch: createApp().fetch, port: config.port }, (info) => {
     log.info('api listening', {
       port: info.port,
-      db: config.dbPath,
+      db: config.db.label,
       relays: config.relays.length,
     });
   });
@@ -57,8 +74,13 @@ function main(): void {
     config.discoveryIntervalMin * 60 * 1000,
   );
   const pruneTimer = setInterval(() => {
-    const removed = pruneProbes();
-    if (removed > 0) log.info('pruned probes', { rows: removed });
+    void pruneProbes()
+      .then((removed) => {
+        if (removed > 0) log.info('pruned probes', { rows: removed });
+      })
+      .catch((err: unknown) => {
+        log.error('prune failed', { reason: err instanceof Error ? err.message : String(err) });
+      });
   }, DAY_MS);
 
   // Startup: probe what we already know, then a full discovery backfill so a fresh
@@ -74,17 +96,16 @@ function main(): void {
     clearInterval(discoveryTimer);
     clearInterval(pruneTimer);
 
+    const stop = (): void => {
+      // closeDb drains the Postgres pool, so it is awaited before the process leaves.
+      void closeDb().finally(() => process.exit(0));
+    };
+
     void inFlight.finally(() => {
       closePool();
-      server.close(() => {
-        closeDb();
-        process.exit(0);
-      });
+      server.close(stop);
       // Do not hang forever on a relay socket that refuses to close.
-      setTimeout(() => {
-        closeDb();
-        process.exit(0);
-      }, 8000).unref();
+      setTimeout(stop, 8000).unref();
     });
   };
 
@@ -92,4 +113,7 @@ function main(): void {
   process.on('SIGTERM', () => shutdown('SIGTERM'));
 }
 
-main();
+void main().catch((err: unknown) => {
+  log.error('startup failed', { reason: err instanceof Error ? err.message : String(err) });
+  process.exit(1);
+});