add structured logging and admin diagnostics to serve

- bincio.serve logger wired into uvicorn output: rebuild steps, upload
  errors, strava-zip progress all now appear in the server log
- _trigger_rebuild: capture stdout/stderr, log errors instead of silently
  discarding; exceptions logged with traceback instead of swallowed
- upload handler: log per-file errors with traceback; include error detail
  in the SSE event sent back to the browser
- strava-zip handler: log imported/error counts on completion
- GET /api/admin/users/{handle}/diag: snapshot of a user's data dir
  (file counts, sizes, index activity counts, pending uploads)
- POST /api/admin/users/{handle}/rebuild-sync: blocking rebuild that
  returns full stdout/stderr — for debugging without SSH log access
- Admin page: Diag button per user opens a modal showing the diag JSON

bincio/serve/cli.py

@@ -76,4 +76,11 @@ def serve(data_dir: str, site_dir: Optional[str], host: str, port: int,
         console.print(f"  Users: [dim]unlimited[/dim]")
     console.print()
 
-    uvicorn.run(srv.app, host=host, port=port, log_level="info")
+    log_config = uvicorn.config.LOGGING_CONFIG.copy()
+    # Make bincio.serve logger emit at INFO through uvicorn's handler
+    log_config["loggers"]["bincio.serve"] = {
+        "handlers": ["default"],
+        "level": "INFO",
+        "propagate": False,
+    }
+    uvicorn.run(srv.app, host=host, port=port, log_level="info", log_config=log_config)

bincio/serve/server.py

@@ -9,6 +9,7 @@ Run via `bincio serve` CLI command.
 from __future__ import annotations
 
 import json
+import logging
 import re
 import secrets
 import shutil
@@ -19,6 +20,8 @@ import uuid
 from pathlib import Path
 from typing import Any, Optional
 
+log = logging.getLogger("bincio.serve")
+
 from fastapi import Cookie, FastAPI, File, Form, HTTPException, Request, Response, UploadFile
 from fastapi.responses import RedirectResponse, StreamingResponse
 from fastapi.middleware.cors import CORSMiddleware
@@ -246,37 +249,52 @@ def _trigger_rebuild(handle: str) -> None:
                 # Fast: only update data, skip Astro build.
                 # Serialised with the same lock: merge_all wipes and recreates
                 # _merged/activities/ — concurrent runs would corrupt each other.
+                log.info("rebuild[%s]: merge-only (no webroot)", _handle)
                 with _rebuild_lock:
-                    subprocess.run(
+                    result = subprocess.run(
                         [uv, "run", "bincio", "render",
                          "--data-dir", _data_dir,
                          "--site-dir", _site_dir,
                          "--handle", _handle,
                          "--no-build"],
-                        stdout=subprocess.DEVNULL,
-                        stderr=subprocess.DEVNULL,
+                        capture_output=True,
+                        text=True,
                     )
+                    if result.returncode != 0:
+                        log.error("rebuild[%s]: merge failed (rc=%d):\n%s\n%s",
+                                  _handle, result.returncode, result.stdout, result.stderr)
+                    else:
+                        log.info("rebuild[%s]: merge done", _handle)
             else:
                 # Full build + rsync — serialised so concurrent uploads don't race
+                log.info("rebuild[%s]: full build + rsync to %s", _handle, _webroot)
                 with _rebuild_lock:
                     result = subprocess.run(
                         [uv, "run", "bincio", "render",
                          "--data-dir", _data_dir,
                          "--site-dir", _site_dir,
                          "--handle", _handle],
-                        stdout=subprocess.DEVNULL,
-                        stderr=subprocess.DEVNULL,
+                        capture_output=True,
+                        text=True,
                     )
-                    if result.returncode == 0:
-                        # Rsync built site to nginx webroot
-                        subprocess.run(
+                    if result.returncode != 0:
+                        log.error("rebuild[%s]: build failed (rc=%d):\n%s\n%s",
+                                  _handle, result.returncode, result.stdout, result.stderr)
+                    else:
+                        log.info("rebuild[%s]: build done, rsyncing", _handle)
+                        rsync = subprocess.run(
                             ["rsync", "-a", "--delete",
                              f"{_site_dir}/dist/", _webroot + "/"],
-                            stdout=subprocess.DEVNULL,
-                            stderr=subprocess.DEVNULL,
+                            capture_output=True,
+                            text=True,
                         )
+                        if rsync.returncode != 0:
+                            log.error("rebuild[%s]: rsync failed (rc=%d):\n%s\n%s",
+                                      _handle, rsync.returncode, rsync.stdout, rsync.stderr)
+                        else:
+                            log.info("rebuild[%s]: rsync done", _handle)
         except Exception:
-            pass  # rebuild failure must never affect the calling request
+            log.exception("rebuild[%s]: unexpected error", _handle)
 
     threading.Thread(target=_run, daemon=True).start()
 
@@ -551,6 +569,127 @@ async def admin_rebuild(
     return JSONResponse({"ok": True})
 
 
+@app.post("/api/admin/users/{handle}/rebuild-sync")
+async def admin_rebuild_sync(
+    handle: str,
+    bincio_session: Optional[str] = Cookie(default=None),
+) -> JSONResponse:
+    """Run merge+rebuild synchronously and return full output. Admin only.
+
+    Unlike /rebuild (fire-and-forget), this blocks until done and returns stdout/stderr.
+    Use for debugging when you need to see what went wrong.
+    """
+    _require_admin(bincio_session)
+    user_dir = _get_data_dir() / handle
+    if not user_dir.is_dir():
+        raise HTTPException(404, f"No data directory for user '{handle}'")
+    if site_dir is None:
+        raise HTTPException(503, "Server has no --site-dir configured; rebuild not available")
+
+    uv = shutil.which("uv") or str(Path.home() / ".local" / "bin" / "uv")
+    cmd = [uv, "run", "bincio", "render",
+           "--data-dir", str(data_dir),
+           "--site-dir", str(site_dir),
+           "--handle", handle,
+           "--no-build"]
+    if webroot:
+        cmd = [uv, "run", "bincio", "render",
+               "--data-dir", str(data_dir),
+               "--site-dir", str(site_dir),
+               "--handle", handle]
+
+    result = subprocess.run(cmd, capture_output=True, text=True, timeout=300)
+    resp: dict[str, Any] = {
+        "ok": result.returncode == 0,
+        "returncode": result.returncode,
+        "stdout": result.stdout,
+        "stderr": result.stderr,
+    }
+
+    if result.returncode == 0 and webroot:
+        rsync = subprocess.run(
+            ["rsync", "-a", "--delete", f"{site_dir}/dist/", str(webroot) + "/"],
+            capture_output=True, text=True, timeout=120,
+        )
+        resp["rsync_returncode"] = rsync.returncode
+        resp["rsync_stdout"] = rsync.stdout
+        resp["rsync_stderr"] = rsync.stderr
+        resp["ok"] = rsync.returncode == 0
+
+    return JSONResponse(resp)
+
+
+@app.get("/api/admin/users/{handle}/diag")
+async def admin_diag(
+    handle: str,
+    bincio_session: Optional[str] = Cookie(default=None),
+) -> JSONResponse:
+    """Return a diagnostic snapshot of a user's data directory. Admin only."""
+    _require_admin(bincio_session)
+    user_dir = _get_data_dir() / handle
+    if not user_dir.is_dir():
+        raise HTTPException(404, f"No data directory for user '{handle}'")
+
+    def _count(path: Path, glob: str = "*") -> int:
+        return sum(1 for f in path.glob(glob) if f.is_file()) if path.exists() else 0
+
+    def _size_mb(path: Path) -> float:
+        if not path.exists():
+            return 0.0
+        return sum(f.stat().st_size for f in path.rglob("*") if f.is_file()) / 1_048_576
+
+    activities_dir = user_dir / "activities"
+    merged_dir = user_dir / "_merged"
+    originals_dir = user_dir / "originals"
+    uploads_dir = user_dir / "_uploads"
+
+    merged_index = merged_dir / "index.json"
+    root_index = user_dir / "index.json"
+
+    merged_activity_count: int | None = None
+    if merged_index.exists():
+        try:
+            idx = json.loads(merged_index.read_text())
+            merged_activity_count = len(idx.get("activities", []))
+        except Exception:
+            merged_activity_count = -1
+
+    root_activity_count: int | None = None
+    if root_index.exists():
+        try:
+            idx = json.loads(root_index.read_text())
+            root_activity_count = len(idx.get("activities", []))
+        except Exception:
+            root_activity_count = -1
+
+    return JSONResponse({
+        "handle": handle,
+        "user_dir": str(user_dir),
+        "activities": {
+            "json_files": _count(activities_dir, "*.json"),
+            "geojson_files": _count(activities_dir, "*.geojson"),
+            "size_mb": round(_size_mb(activities_dir), 2),
+        },
+        "originals": {
+            "exists": originals_dir.exists(),
+            "size_mb": round(_size_mb(originals_dir), 2),
+            "strava_originals": _count(originals_dir / "strava", "*.json") if (originals_dir / "strava").exists() else 0,
+        },
+        "merged": {
+            "exists": merged_dir.exists(),
+            "activity_count_in_index": merged_activity_count,
+            "size_mb": round(_size_mb(merged_dir), 2),
+        },
+        "root_index": {
+            "exists": root_index.exists(),
+            "activity_count": root_activity_count,
+        },
+        "pending_uploads": _count(uploads_dir),
+        "dedup_cache_exists": (user_dir / ".bincio_cache.json").exists(),
+        "athlete_json_exists": (user_dir / "athlete.json").exists(),
+    })
+
+
 def _wipe_user_activities(user_dir: Path) -> int:
     """Delete all extracted activity files and caches for a user.
 
@@ -937,9 +1076,10 @@ async def upload_activity(
                 added += 1
                 any_added = True
                 yield f"data: {json.dumps({'type': 'progress', 'n': n, 'total': total_files, 'name': name, 'status': 'imported'})}\n\n"
-            except Exception:
+            except Exception as exc:
                 errors += 1
-                yield f"data: {json.dumps({'type': 'progress', 'n': n, 'total': total_files, 'name': name, 'status': 'error'})}\n\n"
+                log.error("upload[%s]: failed to process %s: %s", user.handle, name, exc, exc_info=True)
+                yield f"data: {json.dumps({'type': 'progress', 'n': n, 'total': total_files, 'name': name, 'status': 'error', 'detail': str(exc)})}\n\n"
             finally:
                 if not kept:
                     staged.unlink(missing_ok=True)
@@ -999,18 +1139,32 @@ async def upload_strava_zip(
     from bincio.extract.strava_zip import strava_zip_iter
     from bincio.render.merge import merge_all
 
+    log.info("strava-zip[%s]: received %s, privacy=%s", user.handle, file.filename, privacy)
+
     def event_stream():
         any_imported = False
+        imported_count = 0
+        error_count = 0
         try:
             for event in strava_zip_iter(zip_path, dd, privacy=privacy):
                 yield f"data: {json.dumps(event)}\n\n"
-                if event.get("type") == "progress" and event.get("status") == "imported":
+                if event.get("type") == "progress":
+                    status = event.get("status")
+                    if status == "imported":
                         any_imported = True
+                        imported_count += 1
+                    elif status == "error":
+                        error_count += 1
+                        log.warning("strava-zip[%s]: error on %s: %s",
+                                    user.handle, event.get("name"), event.get("detail", ""))
                 if event.get("type") == "done":
+                    log.info("strava-zip[%s]: done — imported=%d errors=%d",
+                             user.handle, imported_count, error_count)
                     if any_imported:
                         merge_all(dd)
                         _trigger_rebuild(user.handle)
         except Exception as exc:
+            log.error("strava-zip[%s]: fatal error: %s", user.handle, exc, exc_info=True)
             yield f"data: {json.dumps({'type': 'error', 'message': str(exc)})}\n\n"
         finally:
             zip_path.unlink(missing_ok=True)

site/src/pages/admin/index.astro

@@ -31,6 +31,15 @@ import Base from '../../layouts/Base.astro';
       </table>
     </div>
 
+    <!-- Diag modal -->
+    <dialog id="diag-dialog" class="rounded-xl bg-zinc-900 border border-zinc-700 p-6 text-white max-w-2xl w-full backdrop:bg-black/60">
+      <div class="flex items-center justify-between mb-4">
+        <h3 class="font-semibold text-sm">Data directory snapshot — <span id="diag-handle" class="text-zinc-400 font-mono"></span></h3>
+        <button id="diag-close" class="text-zinc-500 hover:text-zinc-200 text-xs px-2 py-1 rounded bg-zinc-800">Close</button>
+      </div>
+      <pre id="diag-output" class="text-xs font-mono bg-zinc-950 rounded p-4 overflow-auto max-h-96 text-green-300 whitespace-pre-wrap"></pre>
+    </dialog>
+
     <!-- Confirmation dialog -->
     <dialog id="confirm-dialog" class="rounded-xl bg-zinc-900 border border-zinc-700 p-6 text-white max-w-sm w-full backdrop:bg-black/60">
       <p class="text-sm text-zinc-300 mb-1">Reset all data for <strong id="confirm-handle" class="text-white"></strong>?</p>
@@ -48,6 +57,11 @@ import Base from '../../layouts/Base.astro';
   const tbodyEl     = document.getElementById('user-list')!;
   const dialog      = document.getElementById('confirm-dialog') as HTMLDialogElement;
   const confirmH    = document.getElementById('confirm-handle')!;
+  const diagDialog  = document.getElementById('diag-dialog') as HTMLDialogElement;
+  const diagHandle  = document.getElementById('diag-handle')!;
+  const diagOutput  = document.getElementById('diag-output')!;
+  document.getElementById('diag-close')!.addEventListener('click', () => diagDialog.close());
+  diagDialog.addEventListener('click', e => { if (e.target === diagDialog) diagDialog.close(); });
   const confirmOk     = document.getElementById('confirm-ok')!;
   const confirmCancel = document.getElementById('confirm-cancel')!;
 
@@ -117,6 +131,11 @@ import Base from '../../layouts/Base.astro';
           <td class="px-4 py-3 text-right text-zinc-400 tabular-nums">${u.images_mb > 0 ? fmt(u.images_mb) : '—'}</td>
           <td class="px-4 py-3 text-right">
             <div class="flex gap-2 justify-end">
+              <button
+                class="diag-btn text-xs px-3 py-1.5 rounded-lg bg-zinc-800 hover:bg-zinc-700 text-zinc-400 hover:text-zinc-200 transition-colors"
+                data-handle="${u.handle}"
+                title="Show diagnostic snapshot of this user's data directory"
+              >Diag</button>
               <button
                 class="rebuild-btn text-xs px-3 py-1.5 rounded-lg bg-zinc-800 hover:bg-zinc-700 text-zinc-400 hover:text-zinc-200 transition-colors"
                 data-handle="${u.handle}"
@@ -138,6 +157,22 @@ import Base from '../../layouts/Base.astro';
       `;
     }).join('');
 
+    tbodyEl.querySelectorAll<HTMLButtonElement>('.diag-btn').forEach(btn => {
+      btn.addEventListener('click', async () => {
+        const h = btn.dataset.handle!;
+        diagHandle.textContent = h;
+        diagOutput.textContent = 'Loading…';
+        diagDialog.showModal();
+        try {
+          const r = await fetch(`/api/admin/users/${h}/diag`, { credentials: 'include' });
+          const d = await r.json();
+          diagOutput.textContent = JSON.stringify(d, null, 2);
+        } catch (err) {
+          diagOutput.textContent = String(err);
+        }
+      });
+    });
+
     tbodyEl.querySelectorAll<HTMLButtonElement>('.rebuild-btn').forEach(btn => {
       btn.addEventListener('click', async () => {
         const h = btn.dataset.handle!;