“Stay committed to your decisions, but stay flexible in your approach.”
— Tony Robbins
After abandoning my earlier plans to jump into the application publishing process, I started to take a look at the missing error recovery needs for all of these inter-instance interactions. One thing that I had always planned to do at some point was to create an activity log of all transactions between instances. My idea was not to sync the logs across all instances, but to have a record in each instance of the things that went on with that particular instance. On the Host instance, such a log could provide the basis for some form of periodic recovery process that scanned the log for failed transactions and then made another attempt to put the transaction through again. After giving that some thought, though, I decided that a better approach would be to just scan each instance for instances, applications, and versions, and then attempt to push over anything that was missing compared to what was present on the Host. I still want to build an activity log at some point, but I don’t think that I want to use it as a basis for error recovery. I think it would be more straightforward to just compare the lists of records on each instance with the master lists on the Host and then try to correct any deficiencies.
That’s the plan today, anyway, but plans do have a way of changing over time, so who knows how things will come out once I start putting all of the pieces together. Right now, though, this seems like the better way to go.
One little thing that have been wanting to do for some time was to add another field to the version record to indicate the version of ServiceNow that was used to build the Update Set. There is a System Property that contains this information, so I all I really needed to do was to add the field and then add a line of code to the version record creation function to pull that value out of the property and stuff it into the new field. The name of the property is glide.buildtag.last, and the name of the field that I added is built_on.
Once I added the new field to the version record, I opened up the ApplicationPublisher Script Include, which creates the version record, and added the following line to the function that builds the record:
versionGR.setValue('built_on', gs.getProperty('glide.buildtag.last'));
I also had to modify the function that sent the version record over to other instances to pass on the new value. Since I copied that code instead of consolidating the logic into a single, reusable function, I had to do that in two places, in the ApplicationPublisher and then again in the CollaborationStoreUtils (I really need to collapse that code into a single set of functions that will for both cases). In both places, I added the following line:
payload.built_on = versionGR.getDisplayValue('built_on');
This was not any kind of a major change, but it was something that I had been meaning to do for a long time, and so while I was in looking at the code, I decided to just go ahead and do it. Next time, we will focus on some real work to start building out some kind of error recovery process so that we can ensure that all of the instances in the community are always kept up to date, even if they miss an update in real time for whatever reason.
