Google App Engine agressively caches stuff. They are currently serving
a 24-hour old version of my CSS after multiple updates and re-deploys.
Ughhh. From their docs:
> After a file is transmitted with a given expiration time, there is
> generally no way to clear it out of web-proxy caches, even if the user
> clears their own browser cache. Re-deploying a new version of the app
> will not reset any caches. Therefore, if you ever plan to modify a
> static file, it should have a short (less than one hour) expiration
> time. In most cases, the default 10-minute expiration time is
> appropriate.
The only way to break this for now is to change the CSS *directory*.
In the future I think we have to be sure to set the private cache
control header, which lets browsers cache it, but not public CDNs.
See: https://cloud.google.com/appengine/docs/standard/python3/how-requests-are-handled
As I expected, on Google App Engine we can't write the cache file
to the current working directory. I modified csv-metadata-quality
CLI to check for the REQUESTS_CACHE_DIR environment variable so we
don't really have to do anything different other than setting the
variable.
This works locally, but I don't think it will work on App Engine
because csv-metadata-quality uses requests-cache and creates the
agrovoc-response-cache.sqlite file in the current working directory.
Re-work upload and file processing so they are in the same Python
function. Now I will start exposing other command line options in
the form, like unsafe fixes, excluding fields, etc. Now I see tha
t it is easier to save the POSTed file and process it in the same
function so I don't have to pass around the other POSTed form val
ues as URL query parameters.
Now, as a result of changing the flow above, I also had to make a
change to the way I show the results page. Instead of processing
the file and returning the rendered results to the user directly,
I process the file, save the rendered results to /tmp, and return
a redirect to the user to the results page.
I originally wanted to use an "uploads" directory or something, but
it seems we can only write to /tmp on Google App Engine. They really
want you to buy storage or database services! This is memory mapped
so it disappears when you re-deploy.
I set this but never actually passed it to the subprocess. Now I'm
wondering if I actually need it, or if that was just when I was tr-
ying to import the csv-metadata-quality module?
Alan Orth