treewide: rework uci apply workflow

Switch to rpcd based uci apply/rollback workflow which helps to avoid soft-
bricking devices by requiring an explicit confirmation call after config
apply.

When a user now clicks "Save & Apply", LuCI first issues a call to uci apply
which commits and reloads configuration, then goes into a polling countdown
mode where it repeatedly attempts to call uci confirm.

If the committed configuration is sane, the confirm call will go through and
cancel rpcd's pending rollback timer.

If the configuration change leads to a loss of connectivity (e.g. due to bad
firewall rules or similar), the rollback mechanism will kick in after the
timeout and revert configuration files and pending changes to the pre-apply
state.

In order to cover such rare cases where a lost of connectivity is expected
and desired, the user is offered an "unchecked" apply option after timing
out, which allows committing and applying the changes anyway, without the
extra safety checks.

As a consequence of this change, the luci-reload mechanism is now completely
unsused since rpcd uses ubus config reload signals to reload affected
services, which means that only procd-enabled services will receive proper
reload treatment with the new workflow.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

3 files changed, 195 insertions, 46 deletions

diff --git a/modules/luci-base/luasrc/view/cbi/apply_widget.htm b/modules/luci-base/luasrc/view/cbi/apply_widget.htm
new file mode 100644
index 0000000000..543ef0b80b
--- /dev/null
+++ b/modules/luci-base/luasrc/view/cbi/apply_widget.htm
@@ -0,0 +1,181 @@
+<% export("cbi_apply_widget", function(redirect_ok) -%>
+<style type="text/css">
+	#cbi_apply_status {
+		display: flex;
+		flex-wrap: wrap;
+		min-height: 32px;
+		align-items: center;
+		margin: 1.5em 0 1.5em 0;
+	}
+
+	#cbi_apply_status > h4,
+	#cbi_apply_status > p,
+	#cbi_apply_status > div {
+		flex-basis: 100%;
+	}
+
+	#cbi_apply_status > img {
+		margin-right: 1em;
+		flex-basis: 32px;
+	}
+
+	#cbi_apply_status + script + .cbi-section {
+		margin-top: -1em;
+	}
+
+	.alert-message.notice {
+		background: linear-gradient(#fff 0%, #eee 100%);
+	}
+</style>
+
+<script type="text/javascript" src="<%=resource%>/cbi.js"></script>
+<script type="text/javascript">//<![CDATA[
+	var xhr = new XHR(),
+	    stat, indicator,
+	    uci_apply_auth = { sid: '<%=luci.dispatcher.context.authsession%>', token: '<%=token%>' },
+	    uci_apply_rollback = <%=math.max(luci.config and luci.config.apply and luci.config.apply.rollback or 30, 30)%>,
+	    uci_apply_holdoff = <%=math.max(luci.config and luci.config.apply and luci.config.apply.holdoff or 4, 1)%>,
+	    uci_apply_timeout = <%=math.max(luci.config and luci.config.apply and luci.config.apply.timeout or 5, 1)%>,
+	    uci_apply_display = <%=math.max(luci.config and luci.config.apply and luci.config.apply.display or 1.5, 1)%>;
+
+	function uci_rollback(checked) {
+		if (checked) {
+			stat.classList.remove('notice');
+			stat.classList.add('warning');
+			stat.innerHTML = '<img src="<%=resource%>/icons/loading.gif" alt="" style="vertical-align:middle" /> ' +
+			                 '<%:Failed to confirm apply within %ds, waiting for rollback…%>'.format(uci_apply_rollback);
+
+			var call = function(r) {
+				if (r.status === 204) {
+					stat.innerHTML = '<h4><%:Configuration has been rolled back!%></h4>' +
+						'<p><%:The device could not be reached within %d seconds after applying the pending changes, which caused the configuration to be rolled back for safety reasons. If you believe that the configuration changes are correct nonetheless, perform an unchecked configuration apply. Alternatively, you can dismiss this warning and edit changes before attempting to apply again, or revert all pending changes to keep the currently working configuration state.%></p>'.format(uci_apply_rollback) +
+						'<div class="right">' +
+							'<input type="button" class="btn" onclick="this.parentNode.parentNode.style.display=\'none\'" value="<%:Dismiss%>" /> ' +
+							'<input type="button" class="btn" onclick="uci_revert()" value="<%:Revert changes%>" /> ' +
+							'<input type="button" class="btn danger" onclick="uci_apply(false)" value="<%:Apply unchecked%>" />' +
+						'</div>';
+
+					return;
+				}
+
+				xhr.post('<%=url("admin/uci/confirm")%>', uci_apply_auth, call, uci_apply_timeout * 1000);
+			};
+
+			call({ status: 0 });
+		}
+		else {
+			stat.classList.remove('notice');
+			stat.classList.add('warning');
+			stat.innerHTML = '<h4><%:Device unreachable!%></h4>' +
+				'<p><%:Could not regain access to the device after applying the configuration changes. You might need to reconnect if you modified network related settings such as the IP address or wireless security credentials.%></p>';
+		}
+	}
+
+	function uci_confirm(checked, deadline) {
+		var tt;
+		var ts = Date.now();
+
+		stat = document.getElementById('cbi_apply_status');
+		stat.style.display = '';
+		stat.classList.remove('warning');
+		stat.classList.add('notice');
+
+		indicator = document.querySelector('.uci_change_indicator');
+
+		var call = function(r) {
+			if (Date.now() >= deadline) {
+				uci_rollback(checked);
+				return;
+			}
+			else if (r && (r.status === 200 || r.status === 204)) {
+				if (indicator)
+					indicator.style.display = 'none';
+
+				stat.innerHTML = '<%:Configuration has been applied.%>';
+
+				window.clearTimeout(tt);
+				window.setTimeout(function() {
+					stat.style.display = 'none';
+					<% if redirect_ok then %>location.href = decodeURIComponent('<%=luci.util.urlencode(redirect_ok)%>');<% end %>
+				}, uci_apply_display * 1000);
+
+				return;
+			}
+
+			xhr.post('<%=url("admin/uci/confirm")%>', uci_apply_auth, call, uci_apply_timeout * 1000);
+		};
+
+		var tick = function() {
+			var now = Date.now();
+
+			stat.innerHTML = '<img src="<%=resource%>/icons/loading.gif" alt="" style="vertical-align:middle" /> ' +
+			                 '<%:Waiting for configuration to get applied… %ds%>'.format(Math.max(Math.floor((deadline - Date.now()) / 1000), 0));
+
+			if (now >= deadline)
+				return;
+
+			tt = window.setTimeout(tick, 1000 - (now - ts));
+			ts = now;
+		};
+
+		tick();
+
+		/* wait a few seconds for the settings to become effective */
+		window.setTimeout(call, Math.max(uci_apply_holdoff * 1000 - ((ts + uci_apply_rollback * 1000) - deadline), 1));
+	}
+
+	function uci_apply(checked) {
+		stat = document.getElementById('cbi_apply_status');
+		stat.style.display = '';
+		stat.classList.remove('warning');
+		stat.classList.add('notice');
+		stat.innerHTML = '<img src="<%=resource%>/icons/loading.gif" alt="" style="vertical-align:middle" /> ' +
+		                 '<%:Starting configuration apply…%>';
+
+		xhr.post('<%=url("admin/uci")%>/' + (checked ? 'apply_rollback' : 'apply_unchecked'), uci_apply_auth, function(r) {
+			if (r.status === (checked ? 200 : 204)) {
+				uci_confirm(checked, Date.now() + uci_apply_rollback * 1000);
+			}
+			else if (checked && r.status === 204) {
+				stat.innerHTML = '<%:There are no changes to apply.%>';
+				window.setTimeout(function() {
+					stat.style.display = 'none';
+					<% if redirect_ok then %>location.href = decodeURIComponent('<%=luci.util.urlencode(redirect_ok)%>');<% end %>
+				}, uci_apply_display * 1000);
+			}
+			else {
+				stat.classList.add('warning');
+				stat.classList.remove('notice');
+				stat.innerHTML = '<%_Apply request failed with status <code>%h</code>%>'.format(r.responseText || r.statusText || r.status);
+			}
+		});
+	}
+
+	function uci_revert() {
+		stat = document.getElementById('cbi_apply_status');
+		stat.style.display = '';
+		stat.classList.remove('warning');
+		stat.classList.add('notice');
+		stat.innerHTML = '<img src="<%=resource%>/icons/loading.gif" alt="" style="vertical-align:middle" /> ' +
+		                 '<%:Reverting configuration…%>';
+
+		xhr.post('<%=url("admin/uci/revert")%>', uci_apply_auth, function(r) {
+			if (r.status === 200) {
+				stat.innerHTML = '<%:Changes have been reverted.%>';
+				window.setTimeout(function() {
+					<% if redirect_ok then -%>
+						location.href = decodeURIComponent('<%=luci.util.urlencode(redirect_ok)%>');
+					<%- else -%>
+						window.location = window.location.href.split('#')[0];
+					<%- end %>
+				}, uci_apply_display * 1000);
+			}
+			else {
+				stat.classList.add('warning');
+				stat.classList.remove('notice');
+				stat.innerHTML = '<%_Revert request failed with status <code>%h</code>%>'.format(r.statusText || r.status);
+			}
+		});
+	}
+//]]></script>
+<%-	end) %>
diff --git a/modules/luci-base/luasrc/view/cbi/apply_xhr.htm b/modules/luci-base/luasrc/view/cbi/apply_xhr.htm
deleted file mode 100644
index daa57c1db7..0000000000
--- a/modules/luci-base/luasrc/view/cbi/apply_xhr.htm
+++ /dev/null
@@ -1,43 +0,0 @@
-<% export("cbi_apply_xhr", function(id, configs, redirect) -%>
-<fieldset class="cbi-section" id="cbi-apply-<%=id%>">
-	<legend><%:Applying changes%></legend>
-	<script type="text/javascript">//<![CDATA[
-		var apply_xhr = new XHR();
-
-		apply_xhr.post('<%=url('servicectl/restart', table.concat(configs, ","))%>', { token: '<%=token%>' },
-			function() {
-				var checkfinish = function() {
-					apply_xhr.get('<%=url('servicectl/status')%>', null,
-						function(x) {
-							if( x.responseText == 'finish' )
-							{
-								var e = document.getElementById('cbi-apply-<%=id%>-status');
-								if( e )
-								{
-									e.innerHTML = '<%:Configuration applied.%>';
-									window.setTimeout(function() {
-										e.parentNode.style.display = 'none';
-										<% if redirect then %>location.href='<%=redirect%>';<% end %>
-									}, 1000);
-								}
-							}
-							else
-							{
-								var e = document.getElementById('cbi-apply-<%=id%>-status');
-								if( e && x.responseText ) e.innerHTML = x.responseText;
-
-								window.setTimeout(checkfinish, 1000);
-							}
-						}
-					);
-				}
-
-				window.setTimeout(checkfinish, 1000);
-			}
-		);
-	//]]></script>
-
-	<img src="<%=resource%>/icons/loading.gif" alt="<%:Loading%>" style="vertical-align:middle" />
-	<span id="cbi-apply-<%=id%>-status"><%:Waiting for changes to be applied...%></span>
-</fieldset>
-<%-	end) %>
diff --git a/modules/luci-base/luasrc/view/cbi/map.htm b/modules/luci-base/luasrc/view/cbi/map.htm
index e3210add63..69ef3615a2 100644
--- a/modules/luci-base/luasrc/view/cbi/map.htm
+++ b/modules/luci-base/luasrc/view/cbi/map.htm
@@ -2,12 +2,23 @@
 	<div class="errorbox"><%=pcdata(msg)%></div>
 <%- end end -%>
 
-<%-+cbi/apply_xhr-%>
-
 <div class="cbi-map" id="cbi-<%=self.config%>">
 	<% if self.title and #self.title > 0 then %><h2 name="content"><%=self.title%></h2><% end %>
 	<% if self.description and #self.description > 0 then %><div class="cbi-map-descr"><%=self.description%></div><% end %>
-	<%- if firstmap and applymap then cbi_apply_xhr(self.config, parsechain, redirect) end -%>
+	<%- if firstmap and (applymap or confirmmap) then -%>
+		<%+cbi/apply_widget%>
+		<% cbi_apply_widget(redirect) %>
+		<div class="alert-message" id="cbi_apply_status" style="display:none"></div>
+		<script type="text/javascript">
+			document.addEventListener("DOMContentLoaded", function() {
+				<% if confirmmap then -%>
+					uci_confirm(true, Date.now() + <%=confirmmap%> * 1000);
+				<%- else -%>
+					uci_apply(true);
+				<%- end %>
+			});
+		</script>
+	<%- end -%>
 
 	<% if self.tabbed then %>
 		<ul class="cbi-tabmenu map">