At the Forge - Bricolage Alerts
The rules are perhaps the most interesting part of the Bricolage alert system because of the relative ease with which nonprogrammers can create and edit them. However, there is the potential for danger with the =~ and !~ operators, which Perl programmers should recognize as indicators of regular expressions. This clearly is a double-edged sword, because regular expressions can be enormously powerful to the enlightened and extremely dangerous (and frustrating) to the ignorant.
So, we can create our alert by choosing Story title from the attribute list on the left side, =~ from the comparison operator list and entering Linux as the value in the text field, giving us:
Story title =~ Linux
We have to use =~ and not =, because we want to look for Linux in any part of the title rather than match the entire title. If we were interested in either Linux or Perl, we would search for:
Story title =~ Linux|Perl
Experienced Perl hackers might be pleasantly surprised to learn that =~ and !~ are case-insensitive here.
The story $title was just moved to $desk
The body of the alert message then contains a different message, but it also can contain variables. For example, you can set the alert to read:
You asked to be notified when Linux-related articles are moved to a new desk. Well, $trig_full_name just moved "$title" to the $desk desk. I hope you're happy now.
When an alert fires, its message is sent to all of the designated recipients in two different ways. An e-mail message is sent to each of the registered users, informing them, with the message we defined above, that the change has taken place. But Bricolage also keeps track of these items within its database, making it easy to keep track of alerts over the Web. For example, if an alert is fired from the Linux-related item we described above, we receive an indication by e-mail. But we also can see a summary of all the alerts we have received on the my alerts page, which you can get to by clicking on the my alerts button located at the top of each screen.
Alerts stay on this screen until they are acknowledged. The alert screen is not meant to be a long-term storage system; rather, it is a simple messaging agent that allows an editor to look at all of the relevant things that have happened to the site in the recent past.
You can acknowledge, and thus remove, an alert from the my alerts page by clicking in one or more check boxes and then selecting the acknowledge checked button at the bottom of the list. You also can acknowledge all of them at once, without having to use check boxes, by clicking on the acknowledge all button.
If I were the editor of a medium-sized Web site, I would spend a great deal of time defining alerts that would let me know when important events had occurred, such as when writers sent items to my desk.
Alerts are an excellent and practical way for Bricolage to bring relevant information to the appropriate user, rather than forcing users to go and seek out the information. But a side benefit of these alerts is they help new Bricolage administrators and programmers understand the different actions that can occur on different objects in the system. A simple example is the user object: we can create an alert that notifies us whenever users are created or deactivated, change their settings or change their password. This sort of alert is clearly uninteresting for editors but can be of supreme importance to system administrators.
A more complex example is the template object, which will be discussed next month. Templates define the ways in which stories are displayed, so it's important to keep track of them and any modifications made to them. Therefore, more items are associated with templates than with users—you can keep track of when a template is deployed, when it is edited and even when it is moved to its desk. Indeed, if you didn't previously understand that templates have their own desk, just like stories, the alert system would have made that clear to you.
I personally have learned quite a bit about Bricolage from poking through the system from different angles, including alert definitions. If you are new to Bricolage and haven't quite figured out how everything works, even after reading the documentation and expanding all of the menus (which is vital if you are to see where the different parts of a Bricolage site are defined and who has permission to set them), looking through the alert definitions makes things clearer. Moreover, if you are unsure of how a particular object is handled in the system, you always can create and register for an alert on that object, disabling it once you learn how it works.
- March 2015 Issue of Linux Journal: System Administration
- High-Availability Storage with HA-LVM
- DNSMasq, the Pint-Sized Super Dæmon!
- Localhost DNS Cache
- Real-Time Rogue Wireless Access Point Detection with the Raspberry Pi
- Days Between Dates: the Counting
- You're the Boss with UBOS
- The Usability of GNOME
- Multitenant Sites
- Linux for Astronomers