Fundamental mod-pagespeed CDN question

[Vinson G]

I've literally spent days trying understand how the pagespeed module works with a CDN and I think I'm close but it looks like bad news for me.

Here's my situation - I have a website running nginx on an AWS server.  Most of the images that this website references are on a CDN (cloudfront) with an s3 origin.  NONE of these images are on the nginx server. 

Those images are horribly un-optimized.  Can pagespeed help in this case?  

I could see it gallantly trying to optimize these images but I'm failing terribly trying to get it update the references properly (here I am using s3 directly, but it shouldn't matter?): 

[Sun, 08 Oct 2017 06:34:11 GMT] [Info] [31604] Inside CSS: Shrinking image `http://s3.amazonaws.com/grate-cms/3b052946-a928-42b0-b389-ff1848b38bde_hero-bg-image1.jpg' (48295 bytes) 
to `http://www-test.example.com/grate-cms/x3b052946-a928-42b0-b389-ff1848b38bde_hero-bg-image1.jpg.pagespeed.ic.8jtm2YhDaI.webp' (11978 bytes)


the above rewritten url throws up a 404. 


It seems pagespeed is creating these optimized files on the nginx server (the pagespeed cache directory) but I don't now how to refer to them without these assets ever existing there originally. 


I found this on the nginx server:
/var/cache/pagespeed/v3/rate.com/http,3A/,2Fwww-test.rate.com/grate-cms/x3b052946-a928-42b0-b389-ff1848b38bde_hero-bg-image1.jpg.pagespeed.ic.8jtm2YhDaI.webp,

I feel it's so close!  but maybe I'm misunderstanding something fundamental. 

[Joshua Marantz]

I think you're close too, but to fully get what you want, you will need to configure CloudFront to point to the server running ngx_pagespeed rather than directly to S3.

Then, on your ngx_pagespeed server, you want to use MapProxyDomain, to map the images served from an S3 origin into a URL path on your ngx_pagespeed server, and then rewrite them to CloudFront so you get the CDN effect.  This will be something like:

   pagespeed MapProxyDomain YOUR_NGX_SERVER_RUNNING_ON_AWS/s3_images YOUR_S3_SERVER/image_subdirectory YOUR_CLOUDFRONT_CDN/s3_images;

Please read the doc for details, and remember you also have to point YOUR_CLOUDFRONT_CDN/s3_images to use YOUR_NGX_SERVER_RUNNING_ON_AWS/s3_images as its origin.  Hope this makes sense!  Please let us know how it goes.

-Josh

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[Vinson G]

Thanks! I was worried it wasn't really possible. I'm gonna check this out today and go all night if I have to. :)

[Vinson G]

So this seems to be working for our CMS images: 

[Mon, 09 Oct 2017 05:56:19 GMT] [Info] [383] https://www-test.example.com/about-test:680: Shrinking image 

`http://d37a408a319q94.cloudfront.net/cms/b1075459-21e7-4155-97cb-e00ddb2ed90c_Hero_Image_2-25.jpg' (237061 bytes) 

to `http://d37a408a319q94.cloudfront.net/cms/350x182xb1075459-21e7-4155-97cb-e00ddb2ed90c_Hero_Image_2-25.jpg.pagespeed.ic.vGX98lwB1z.webp' (9660 bytes)

That re-written URL is now working. 

I still have some issues to resolve but this part seems to be working fine.  Thanks so much for the help!