Stored cache settings

Cache invalidation based on configuration

There are various settings in the Lancache cache containers which will invalidate existing data if they are altered. In an effort to try to catch these, as of February 2020, the containers will now store the current values of these settings alongside the cache data itself.

For new users installing for the first time, this will happen automatically.

For existing users that have data in their cache but no settings file, the container will automatically generate a settings file based upon the containers current configuration, and will note that it has done so during startup.

  Executing hook /hooks/entrypoint-pre.d/05_config_check.sh
  Checking cache configuration
   Could not find CONFIGHASH for existing cachedata
    This is either an upgrade from an older instance of Lancache
    or CONFIGHASH has been deleted intentionally
	
   Creating CONFIGHASH from current live configuration
     Current:  GENERICCACHE_VERSION=2;CACHE_SLICE_SIZE=1m;CACHE_KEY=$uri$slice_range;
	
    See: https://lancache.net/docs/advanced/config-hash/ for more details

For existing containers that already created a settings file, if environment variables are subsequently changed that will invalidate your cache, you will get a message similar to the following when you try to run up the cache

  Executing hook /hooks/entrypoint-pre.d/05_config_check.sh
  Checking cache configuration
   Detected existing cache, checking config hash for consistency

  ERROR: Detected CONFIGHASH does not match current CONFIGHASH
   Detected: GENERICCACHE_VERSION=2;CACHE_SLICE_SIZE=1m;CACHE_KEY=$uri$slice_range;
   Current:  GENERICCACHE_VERSION=2;CACHE_SLICE_SIZE=2m;CACHE_KEY=$uri$slice_range;
    
  ABORTING STARTUP TO AVOID POTENTIALLY INVALIDATING THE CACHE
    
  If you are happy that this cache is valid with the current config changes
  please delete `/<cache_mount>/CONFIGHASH`
    
  See: https://lancache.net/docs/advanced/config-hash/ for more details

This will indicate the existing setting, and the new settings and will require you to manually delete the settings file before the container will fully start.