Trac Announcer System Proposal

Notice: This proposal is superseded by the AdvancedNotification proposal.

The Context

This is a proposal to replace the Trac Notification System with the ​AnnouncerPlugin.

Requirements

Trac Notification API compatibility

This will be needed to not instantly break 30+ Trac plugins using TracNotification system right now (see: plugin listing for details). So after analyzing the current implementation of Trac Notification Api we have to decide on witch classes have to be added to Announcer code to fully replace TracNotification.

i18n requirements

One of the shortcomings of the current e-mail notification system is that there's only one e-mail prepared which is then sent to every receiver. It should be possible to customize the mail according to each user's preferences (e.g. #2625) and a nice customization would be to translate the notification mail to each recipient's preferred language (#8903).

I'd be particularly interested to see how the Formatter / Distributor concepts of the Announcer would deal with that requirement.

Subscription logic

The current system is at the same time too complex with many .ini settings, and too inflexible. Not to mention the bugs ;-)

Some kind of drastic change seems in order. For example, see the suggestion of a Subscribe ticket (notify me when the ticket is changed checkbox / link (ticket:4056#comment:19).

Announcer System

Sequence Diagrams

User Edits Ticket

Event is Dispatched to the Mail Distributor

Mail Distributor Formats and Sends Email

Proposed Announcer Preferences

Consider Notification Tickets

Ticket	Summary	Priority	Status	Type	Milestone
#6217	New notification/cc scheme - notification preferences per ticket	high	new	enhancement	unscheduled
#731	Allow Trac to send commit information email when the " sync "with the repository	normal	new	enhancement	unscheduled
#1660	Patch to get email notification (with diff) of wiki changes	normal	new	enhancement	1.7.1
#2625	Add option to send HTML mail messages	normal	new	enhancement	next-major-releases
#3162	LDAP support for e-mail notification	normal	new	enhancement	next-major-releases
#3914	ticket change notification should contain diff'ed text, not old and new	normal	new	enhancement	next-dev-1.7.x
#4270	Ticket notification emails contain wiki formatting	normal	new	defect	next-major-releases
#4286	Accepts email addresses without validation	normal	new	defect	next-major-releases
#4519	[PATCH] Feature: component owner ticket notification	normal	new	enhancement	next-dev-1.7.x
#4931	notification with SMTP through SSL is not supported (fix included)	normal	new	defect	next-major-releases
#5001	offer possibility to inform users of new releases and changes	normal	new	enhancement	next-major-releases
#5670	[patch] Refactoring of general `NotifyEmail` class to make it easier to subclass	normal	new	enhancement	next-major-releases
#6173	Allow accounts to be disabled, such that they no longer receive email notifications	normal	new	enhancement	next-major-releases
#6219	Excessive time taken by notification can lead to db timeout?	normal	new	defect	next-major-releases
#7073	notify dup subscribers	normal	new	enhancement	next-major-releases
#7793	[PATCH] Mail notifications for a ticket with multiple owners / reporters	normal	new	enhancement	next-major-releases
#8094	Preview who will be notified	normal	new	defect	next-major-releases
#8294	[PATCH] Add GnuPG encryption to email notifications	normal	new	enhancement	unscheduled
#8599	possibility to send complete tickets per mail (full history and attachments included)	normal	new	enhancement	unscheduled
#8607	Option to skip notification to subscribers when a ticket is updated	normal	new	enhancement	next-major-releases
#8945	[PATCH] Send Notification Email with local timezone	normal	new	enhancement	next-major-releases
#9082	Error sending email when smtp_default_domain and/or smtp_from contain unicode	normal	new	defect	unscheduled
#9085	Notification system silently drops failures to unicode email addresses	normal	new	enhancement	next-major-releases
#9971	cannot unsubscribe from bug, no way, no how	normal	new	defect	next-stable-1.4.x
#10023	Trac notification + Exchange 2010	normal	new	enhancement	unscheduled
#10112	notifications strip slashes from email addresses	normal	new	defect	next-stable-1.4.x
#10450	Do not linewrap long URLs in text emails	normal	new	defect	undecided
#10579	Do not use "anonymous" updater's email in ticket notification From	normal	new	enhancement	next-major-releases
#11271	Batch modify notification emails could present a better description of the property change	normal	new	defect	next-stable-1.4.x
#11577	Status is omitted in plain text emails	normal	new	defect	undecided
#11870	Optional notification subscribers for watching components, users, groups, individual resources, ...	normal	new	enhancement	next-dev-1.7.x
#11871	Notification subscriber for @name mentions	normal	new	enhancement	next-dev-1.7.x
#11884	Notification distributor for XMPP	normal	new	enhancement	next-major-releases
#11887	List Ticket Attachments in TracNotification	normal	new	enhancement	next-major-releases
#11889	On-site notifications	normal	new	enhancement	next-major-releases
#11943	Ticket delete notifications	normal	new	enhancement	next-major-releases
#12165	List users included and excluded from notification	normal	new	enhancement	next-major-releases
#12575	Please improve documentation at TracNotification#Customizingthee-mailcontent	normal	new	enhancement	next-stable-1.4.x
#12997	Sending email on ticket attachments with "Replace existing attachment of the same name"	normal	new	defect	next-stable-1.4.x
#13208	Add methods or property that formats default value for NotificationSystem.smtp_subject_prefix	normal	new	enhancement	next-dev-1.7.x
#13283	Per-realm always_{cc, bcc} options	normal	new	enhancement	next-dev-1.7.x
#13499	Trac Email Notifcations Poorly formatted due to line wrap of quoted text	normal	new	enhancement	undecided
#2619	Message-IDs generation should be a little more randomized	low	new	defect	unscheduled
#6078	[PATCH] Enabling multiple email notification for a single user.	low	new	enhancement	unscheduled
#6107	to "watch" a milestone	low	new	enhancement	next-major-releases
#12774	Separator line is shown twice	lowest	new	defect	next-major-releases

Discussion

If Announcer would substitute TracNotification, following tickets would be

Summary

based on 57 results from 04-Aug-2010, ordered by priority

ticket no.	milestone	aims/notes/references	effect of migration
high
#6217	unscheduled	allow for notification settings per ticket and do really fine grained options, like do/not notify on new comment, change of ticket prop|owner|status, etc. have defaults for each registered user apply different defaults depending on formal involvement (related component owner, reporter, etc.)	unchanged - unresolved, discussion needed (too complicated to be useful?) changed - partially solved, since a bunch of user perferences already exists changed - partially solved, since action depending on involvement already exists ref: alternative/refinement of #4056
#9484	0.13	improve current email formatting for long custom text_area names ref: fits nicely with #3914	unknown - probably solved, need to check
normal
#731	unscheduled	sent commit notification	unknown - probably unresolved, need to check ref: IRepositoryChangeListener available as notification trigger (since inclusion of mutirepos branch)
#1660	next-major-0.1X	wiki notification	changed - solved, especially in combination with ​WatchListPlugin ref: new notification system discussion at ​Trac-Dev
#2245	next-major-0.1X	make user settings (email-address) editable by admins	unchanged - unresolved, discussion needed (already resolved by ​th:wiki:TracUserSyncPlugin TracUserSyncPlugin?)
#2311	next-major-0.1X	sent notification on owner change (to old owner) hint: inconsitency, since removal from cc-field triggers notification to removed address/user	unknown - probably unresolved, need to check
#2625	next-major-0.1X	rich format (i.e. HTML) wiki notification	unchanged - unresolved, only 'text/plain' in current Announcer hint: links to references on good HTML email design standards, discussion on ​Trac-Users, hint on Announcer and more

Summary of worth-to-be-propagated requests

• extend user pref: enhance filter/subscription - #4056

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See also: TracNotification, TracDev/Proposals, TracNotification API documentation, Developer reference page for AnnouncerPlugin, related tickets: No results, and ​Trac Notifications mail on Trac-dev