Retrieving sunrise/sunset time from google sometimes gets error message.

[tfabris]

Every night, the Synology NAS log gets one instance of the Info message saying "Problem obtaining sunrise/sunset from Google...". It is expected to happen because the router/firewall on our LAN does a self-healing nightly reboot at 3:30am every night.

I would like to figure out how to suppress this error message during the nightly reboot, but otherwise display the error message at other times.

There is a catch-22 in the code which makes this tricky. Ideally, I would want to skip it when I don't need it. For example, skipping the google search or suppressing the error message when the live stream isn't supposed to be up and running, or skipping the search when the network is down. The problem is, the sunrise/sunset time needs to be "known" in order to accurately make that decision; you can't make a decision based on the sunrise/sunset time before the sunrise/sunset query.

Ideas:

• Simply suppress the error message altogether. Make the message debug-only.
• Hard code some times of day to skip the google search, giving it a wide window in the middle of the night.
• A pre-google-search network test.
• Base it off the previously-saved time, for example, only re-query for a new sunrise-sunset time when it's within a couple hours of the prior sunrise-sunset time.
• Start the script using the previously-saved time for the determination through "this run" and only do the google search after a successful network test at the end of the script.

[tfabris]

Advantages/Disadvantages:

Suppress the message altogether:

• Advantage: Simple/Quick.
• Disadvantage: Don't get early warning about network troubles during off-times.

Hard code times of day to skip the google search:

• Advantage: Will definitely work for my puproses.
• Disadvantage: Perhaps it is not a good universal solution for other people who might use the script.

Pre-google-search network test:

• Advantage: Slightly more control over how the messaging gets handled.
• Disadvantage: Would require a code refactor and some code complication to have it really work good. As it stands right now, simply adding the test and skipping the retrieval would result in the same error message showing up in the log (i.e., not actually fixing the issue).

Only re-query when we're nearing sunrise/sunset:

• Advantage: Fewer queries made to google, it would work for my purposes, and would definitely remove the error message.
• Disadvantage: Bench testing would be a pain because now it won't do the queries unless you're bench testing at specific times of day.

Start the script using the previously-saved time and then only re-query at the end.

• Advantage: Would work for my purposes.
• Disadvantage: Code complication, code is less readable, and it would not gracefully handle the "First time the program is run" situation unless I add even more code complication.

Consider the following instead:

• It's only one message, once at 3:30am.
• It happens to give a nice canary-in-a-coal-mine report of network uptime failures, even when we're running on off-times.

Perhaps should just leave this be?

[tfabris]

On 2019-04-18, looking at the logs I noticed that there were large swaths of time where the retrieval of the sunrise/sunset time got an error, even though the network was up.

When deciding how to handle this, it is thus important to keep in mind that a failure of the google search and a failure of the network will not always go hand in hand.

Other thoughts:

• Simply muting the message (moving it to debug) would cause me to miss cases where there's a problem.

Consider this option:

• Only retrieve the sunrise/sunset once per day, during times like, for example, the noon hour.
• How do do this?
• Perhaps move the retrieval to a separate script which is timed to only run once per day. It already writes to a file, so the main script would just read that file every time. This causes a usability problem if the retrieval script hasn't run yet.
• Instead, perhaps, have it check the datestamp on the stored file and only retrieve a new time if the datestamp says the stored file is more than 24 hours old. If you do that you could also log successful retrievals.

[tfabris]

I've implmented that last idea about only refreshing the google times if the files are old enough.

Note: Need to test this on a Mac Laptop before considering this issue closed. Sometimes I've had issues with the command line parameters to Bash commands not working as expected on a Mac, and this is the first time I'm using the bash "find" command in this script.

[tfabris]

I have placed this code into production on the NAS, but there is still a problem with the code running on the Mac laptop.

Line 870 currently has a problem if the location of the files is in a folder containing a space in the path name. The place where it executes "find (filename)" has a problem if (filename) contains a space. It's embedded in an IF statement and the statement responds with "unary operator expected".

However ADDING QUOTES AROUND THE FILE NAME DOES NOT FIX THE PROBLEM. Grr.

Need to research this issue in detail and get to the bottom of it. In the meantime, the production code should theoretically be working.

[tfabris]

The most recent checkin will address the issue in all environments. The prior code (still running on the production server at this time) works fine on the production server because there are no spaces in the path name, so it's not a critical hurry to get the new code deployed to production yet. Though leave this bug open until the code really is deployed into production.

[tfabris]

Code is deployed to production. Let's see how it does.