Ram Cache with Include list

Hi F5 Community,

 

 

i want to share with you TWO issues i encountered with Ram Cache behaviour on Big IP devices.

 

 

These issues are related to "Include list" usage for "HTTP Ram Cache" profile.

 

 

Here is my testing environnement :

 

- Big IP LTM 10.2.0

 

- 1 VS with a custom HTTP profile (http_cache)

 

- 1 custom HTTP profile with Ram Cache enable

 

- 1 Group with 1 Node (Apache Webserver)

 

 

My Apache webserver pages tree :

 

- index.php (including two resources 1 JS & 1 CSS)

 

 

- objet.js

 

- style.css

 

 

My expectations regarding Ram Cache :

 

- I want Ram Cache to cache only files with extension ".js" and ".css", so in my environnement only the files "objet.js" & "style.css"

 

 

=================

 

1°) First issue :

 

=================

 

When i configure my "http_cache" profile as followed :

 

- Ramcache "Enabled"

 

- Maximum Cache Size "10"

 

- Maximum Entries "10000"

 

- Maximum Age "3600"

 

- Minimum Object Size "500" (default value)

 

- Maximum Object Size "50000" (default value)

 

- URI List Include Lise "*.js" & "*.css"

 

- Ignore Headers "All"

 

- Insert Age Header "Enabled"

 

- Aging Rate "9"

 

 

And then i execute the following request :

 

- GET /index.php

 

 

The Big IP caches the following files "index.php", "objet.js" and "styles.css"

 

-------------

 

bp>profile http http_cache ramcache entry show

 

PROFILE HTTP http_cache - Ramcache Entry:

 

+-> Host: helloworld.com URI: /index.php

 

....

 

+-> Host: helloworld.com URI: /objet.js

 

....

 

+-> Host: helloworld.com URI: /style.css

 

....

 

bp>

 

-------------

 

 

But when i configure RAM Cache profil as this :

 

- Minimum Object Size "0"

 

- Maximum Object Size "0"

 

 

And then execute the following request :

 

- GET /index.php

 

 

The Big IP caches the good files; only "objet.js" and "style.css"

 

-------------

 

bp>profile http http_cache ramcache entry show

 

PROFILE HTTP http_cache - Ramcache Entry:

 

+-> Host: helloworld.com URI: /objet.js

 

....

 

+-> Host: helloworld.com URI: /style.css

 

....

 

bp>

 

-------------

 

 

[CONCLUSION]

 

So my conclusion, to use "Include list" as a filter to cache objects, you need to configure "Minimum & Maximum object size" to 0

 

 

=================

 

2°) Second issue :

 

=================

 

My second issue is related to how to set "Include list".

 

 

[CONFIG 1]

 

In this example, i used the following Ram Cache configuration :

 

- Ramcache "Enabled"

 

- Maximum Cache Size "10"

 

- Maximum Entries "10000"

 

- Maximum Age "3600"

 

- Minimum Object Size "0"

 

- Maximum Object Size "0"

 

- URI List Include List "/*.js" & "/*.css"

 

- Ignore Headers "All"

 

- Insert Age Header "Enabled"

 

- Aging Rate "9"

 

 

If i execute the following requests :

 

- GET /index.php

 

- GET /index.php?page=js&value=john

 

 

The Big IP caches well "objet.js" and "style.css", but also "index.php?page=js&value=john" what it's not the expected behaviour.

 

-------------

 

bp>profile http http_cache ramcache entry show

 

PROFILE HTTP http_cache - Ramcache Entry:

 

+-> Host: helloworld.com URI: /index.php?page=js&value=john

 

....

 

+-> Host: helloworld.com URI: /objet.js

 

....

 

+-> Host: helloworld.com URI: /style.css

 

....

 

bp>

 

-------------

 

 

[CONFIG 2]

 

With this configuration :

 

- URI List Include List "/*\.js$" & "/*\.css$"

 

- GET /index.php

 

- GET /index.php?page=js&value=john

 

 

The Big IP caches well "objet.js" and "style.css", and NOT "index.php?page=js&value=john" what it's the expected behaviour.

 

-------------

 

bp>profile http http_cache ramcache entry show

 

PROFILE HTTP http_cache - Ramcache Entry:

 

+-> Host: helloworld.com URI: /objet.js

 

....

 

+-> Host: helloworld.com URI: /style.css

 

....

 

bp>

 

-------------

 

 

[CONFIG 3]

 

With this configuration :

 

- URI List Include List "*.js" & "*.css"

 

- GET /index.php

 

- GET /index.php?page=js&value=john

 

- GET /index.php?page=js&value=johnjs

 

 

The Big IP caches well "objet.js" and "style.css", and not "index.php?page=js&value=john" neither "index.php?page=js&value=johnjs" what it's the expected behaviour.

 

-------------

 

bp>profile http http_cache ramcache entry show

 

PROFILE HTTP http_cache - Ramcache Entry:

 

+-> Host: helloworld.com URI: /objet.js

 

....

 

+-> Host: helloworld.com URI: /style.css

 

....

 

bp>

 

-------------

 

 

[CONCLUSION]

 

In my conclusion, the way Big IP reads "Include list" entries is different according if it starts with "/" or not.

 

- When "Include list" entry starts with "/" => RegEx

 

- When "Include list" entry doesn't start with "/" => Pattern String (as for HTTP Class)

 

 

What do you think about my analysis ? Did you encounter these issues ?