virsh: add net-event command

Add 'virsh net-event --list' and 'virsh net-event [net] --event=name
[--loop] [--timeout]'.  Very similar to 'virsh event'.

* tools/virsh.pod (net-event): Document new command.
* tools/virsh-network.c (vshNetworkEventToString, vshNetEventData)
(vshEventLifecyclePrint, cmdNetworkEvent): New struct and
functions.
Signed-off-by: NEric Blake <eblake@redhat.com>

tools/virsh-network.c

 /*
  * virsh-network.c: Commands to manage network
  *
- * Copyright (C) 2005, 2007-2013 Red Hat, Inc.
+ * Copyright (C) 2005, 2007-2014 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -1130,6 +1130,169 @@ cmdNetworkEdit(vshControl *ctl, const vshCmd *cmd)
     return ret;
 }
 
+
+/*
+ * "net-event" command
+ */
+static const char *
+vshNetworkEventToString(int event)
+{
+    const char *ret = _("unknown");
+    switch ((virNetworkEventLifecycleType) event) {
+    case VIR_NETWORK_EVENT_DEFINED:
+        ret = _("Defined");
+        break;
+    case VIR_NETWORK_EVENT_UNDEFINED:
+        ret = _("Undefined");
+        break;
+    case VIR_NETWORK_EVENT_STARTED:
+        ret = _("Started");
+        break;
+    case VIR_NETWORK_EVENT_STOPPED:
+        ret = _("Stopped");
+        break;
+    case VIR_NETWORK_EVENT_LAST:
+        break;
+    }
+    return ret;
+}
+
+struct vshNetEventData {
+    vshControl *ctl;
+    bool loop;
+    int count;
+};
+typedef struct vshNetEventData vshNetEventData;
+
+VIR_ENUM_DECL(vshNetworkEvent)
+VIR_ENUM_IMPL(vshNetworkEvent,
+              VIR_NETWORK_EVENT_ID_LAST,
+              "lifecycle")
+
+static void
+vshEventLifecyclePrint(virConnectPtr conn ATTRIBUTE_UNUSED,
+                       virNetworkPtr net,
+                       int event,
+                       int detail ATTRIBUTE_UNUSED,
+                       void *opaque)
+{
+    vshNetEventData *data = opaque;
+
+    if (!data->loop && data->count)
+        return;
+    vshPrint(data->ctl, _("event 'lifecycle' for network %s: %s\n"),
+             virNetworkGetName(net), vshNetworkEventToString(event));
+    data->count++;
+    if (!data->loop)
+        vshEventDone(data->ctl);
+}
+
+static const vshCmdInfo info_network_event[] = {
+    {.name = "net-event",
+     .data = N_("Network Events")
+    },
+    {.name = "desc",
+     .data = N_("List event types, or wait for network events to occur")
+    },
+    {.name = NULL}
+};
+
+static const vshCmdOptDef opts_network_event[] = {
+    {.name = "network",
+     .type = VSH_OT_DATA,
+     .help = N_("filter by network name or uuid")
+    },
+    {.name = "event",
+     .type = VSH_OT_DATA,
+     .help = N_("which event type to wait for")
+    },
+    {.name = "loop",
+     .type = VSH_OT_BOOL,
+     .help = N_("loop until timeout or interrupt, rather than one-shot")
+    },
+    {.name = "timeout",
+     .type = VSH_OT_INT,
+     .help = N_("timeout seconds")
+    },
+    {.name = "list",
+     .type = VSH_OT_BOOL,
+     .help = N_("list valid event types")
+    },
+    {.name = NULL}
+};
+
+static bool
+cmdNetworkEvent(vshControl *ctl, const vshCmd *cmd)
+{
+    virNetworkPtr net = NULL;
+    bool ret = false;
+    int eventId = -1;
+    int timeout = 0;
+    vshNetEventData data;
+    const char *eventName = NULL;
+    int event;
+
+    if (vshCommandOptBool(cmd, "list")) {
+        size_t i;
+
+        for (i = 0; i < VIR_NETWORK_EVENT_ID_LAST; i++)
+            vshPrint(ctl, "%s\n", vshNetworkEventTypeToString(i));
+        return true;
+    }
+
+    if (vshCommandOptString(cmd, "event", &eventName) < 0)
+        return false;
+    if (!eventName) {
+        vshError(ctl, "%s", _("either --list or event type is required"));
+        return false;
+    }
+    if ((event = vshNetworkEventTypeFromString(eventName) < 0)) {
+        vshError(ctl, _("unknown event type %s"), eventName);
+        return false;
+    }
+
+    data.ctl = ctl;
+    data.loop = vshCommandOptBool(cmd, "loop");
+    data.count = 0;
+    if (vshCommandOptTimeoutToMs(ctl, cmd, &timeout) < 0)
+        return false;
+
+    if (vshCommandOptBool(cmd, "network"))
+        net = vshCommandOptNetwork(ctl, cmd, NULL);
+    if (vshEventStart(ctl, timeout) < 0)
+        goto cleanup;
+
+    if ((eventId = virConnectNetworkEventRegisterAny(ctl->conn, net, event,
+                                                     VIR_NETWORK_EVENT_CALLBACK(vshEventLifecyclePrint),
+                                                     &data, NULL)) < 0)
+        goto cleanup;
+    switch (vshEventWait(ctl)) {
+    case VSH_EVENT_INTERRUPT:
+        vshPrint(ctl, "%s", _("event loop interrupted\n"));
+        break;
+    case VSH_EVENT_TIMEOUT:
+        vshPrint(ctl, "%s", _("event loop timed out\n"));
+        break;
+    case VSH_EVENT_DONE:
+        break;
+    default:
+        goto cleanup;
+    }
+    vshPrint(ctl, _("events received: %d\n"), data.count);
+    if (data.count)
+        ret = true;
+
+cleanup:
+    vshEventCleanup(ctl);
+    if (eventId >= 0 &&
+        virConnectNetworkEventDeregisterAny(ctl->conn, eventId) < 0)
+        ret = false;
+    if (net)
+        virNetworkFree(net);
+    return ret;
+}
+
+
 const vshCmdDef networkCmds[] = {
     {.name = "net-autostart",
      .handler = cmdNetworkAutostart,
@@ -1167,6 +1330,12 @@ const vshCmdDef networkCmds[] = {
      .info = info_network_edit,
      .flags = 0
     },
+    {.name = "net-event",
+     .handler = cmdNetworkEvent,
+     .opts = opts_network_event,
+     .info = info_network_event,
+     .flags = 0
+    },
     {.name = "net-info",
      .handler = cmdNetworkInfo,
      .opts = opts_network_info,

tools/virsh.pod

@@ -2327,6 +2327,21 @@ except that it does some error checking.
 The editor used can be supplied by the C<$VISUAL> or C<$EDITOR> environment
 variables, and defaults to C<vi>.
 
+=item B<net-event> {[I<network>] I<event> [I<--loop>] [I<--timeout>
+I<seconds>] | I<--list>}
+
+Wait for a class of network events to occur, and print appropriate details
+of events as they happen.  The events can optionally be filtered by
+I<network>.  Using I<--list> as the only argument will provide a list
+of possible I<event> values known by this client, although the connection
+might not allow registering for all these events.
+
+By default, this command is one-shot, and returns success once an event
+occurs; you can send SIGINT (usually via C<Ctrl-C>) to quit immediately.
+If I<--timeout> is specified, the command gives up waiting for events
+after I<seconds> have elapsed.   With I<--loop>, the command prints all
+events until a timeout or interrupt key.
+
 =item B<net-info> I<network>
 
 Returns basic information about the I<network> object.