feat(admin): the Logs page searches every row, shows failures and downloads them

The search box filtered only the 100 rows on screen, in the browser: an
older row seemed not to exist. The page now searches on the server, in
every row's user, host, VM, VM UUID, message and IP, as plain text, and
can show the failed rows only; its pages keep the search.

Failed rows are marked red, dates carry the year and the time zone, and
a VM's rows link to the VM while it is in the panel. Excel downloads the
rows the search chooses, all pages of them, with the VM report's
workbook (text stays text).

admin/views.py

@@ -7,14 +7,16 @@ from django.contrib import messages
 from django.contrib.auth import update_session_auth_hash
 from django.contrib.auth.models import Group, User
 from django.core.paginator import Paginator
+from django.http import HttpResponse
 from django.db import transaction
 from django.db.models import Count, Q
 from django.shortcuts import get_object_or_404, redirect, render
 from django.utils import timezone
-from django.utils.http import url_has_allowed_host_and_scheme
+from django.utils.http import url_has_allowed_host_and_scheme, urlencode
 from django.utils.translation import gettext_lazy as _
 from django.views.decorators.http import require_POST
 from instances.models import InstanceTombstone
+from instances.report import workbook
 from logs.audit import audit, changed_fields, snapshot
 from logs.models import Logs
 
@@ -254,11 +256,54 @@ def user_unblock(request, pk):
     return redirect("admin:user_list")
 
 
+def _logs(request):
+    """The Logs rows the search and the failed-only box choose, newest first,
+    and the query that chooses them again."""
+    rows = Logs.objects.order_by("-date", "-id")
+    text = request.GET.get("q", "").strip()
+    failed = bool(request.GET.get("failed"))
+    if text:
+        rows = rows.filter(Q(user__icontains=text) | Q(host__icontains=text) | Q(instance__icontains=text)
+                           | Q(instance_uuid__icontains=text) | Q(message__icontains=text) | Q(ip__icontains=text))
+    if failed:
+        rows = rows.filter(success=False)
+    query = urlencode([(key, value) for key, value in (("q", text), ("failed", "1" if failed else "")) if value])
+    return rows, text, failed, query
+
+
+def _result(success):
+    return _("Unknown") if success is None else _("Done") if success else _("Failed")
+
+
 @superuser_only
 def logs(request):
-    paginator = Paginator(Logs.objects.order_by("-date", "-id"), int(app_settings.LOGS_PER_PAGE))
-    logs = paginator.get_page(request.GET.get("page"))
-    return render(request, "admin/logs.html", {"logs": logs})
+    rows, text, failed, query = _logs(request)
+    logs = Paginator(rows, int(app_settings.LOGS_PER_PAGE)).get_page(request.GET.get("page"))
+    # a VM's rows link to it while it is in the panel
+    vms = dict(Instance.objects.filter(uuid__in={log.instance_uuid for log in logs if log.instance_uuid})
+               .values_list("uuid", "pk"))
+    for log in logs:
+        log.vm_pk = vms.get(log.instance_uuid)
+    return render(request, "admin/logs.html", {"logs": logs, "q": text, "failed": failed, "query": query,
+                                               "time_zone": timezone.get_current_timezone_name()})
+
+
+@superuser_only
+def logs_export(request):
+    """The rows the Logs page shows for the same search, every page of them,
+    as an Excel workbook."""
+    rows, text, failed, _query = _logs(request)
+    zone = timezone.get_current_timezone_name()
+    header = [f"Date ({zone})", "User", "Host", "VM", "VM UUID", "Message", "Result", "IP"]
+    data = [[timezone.localtime(log.date).strftime("%Y-%m-%d %H:%M:%S"), log.user, log.host, log.instance,
+             log.instance_uuid, log.message, str(_result(log.success)), log.ip or ""] for log in rows.iterator()]
+    notes = [f"Search: {text}" if text else "Search: none", "Failed only" if failed else "All results",
+             f"Rows: {len(data)}", f"Times in {zone}"]
+    response = HttpResponse(workbook("Logs", header, data, "About", notes),
+                            content_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
+    name = f"webvirtcloud-logs-{timezone.localtime():%Y%m%d-%H%M%S}.xlsx"
+    response["Content-Disposition"] = f'attachment; filename="{name}"'
+    return response
 
 
 @superuser_only