Allow cache to be bypassed

[GoogleCodeExporter]

The new cache logic is excellent but it can sometimes be inappropriate.

For example when creating a root filesystem using OpenEmbedded we do not want 
an extra copy of the package files from the deploy directory to the cache 
directory, we should be able to install directly from the deploy directory.

For systems with very little free disk space, when performing an install from a 
remote package feed we may wish to download each package to a tmp dir, install 
it and then remove it from the tmp dir before downloading the next package.

To support these use cases a '--nocache' argument and 'nocache' option should 
be added.

Original issue reported on code.google.com by paul.betafive on 8 May 2014 at 2:51

[GoogleCodeExporter]

Original comment by paul.betafive on 8 May 2014 at 2:55

• Changed state: Accepted

[GoogleCodeExporter]

I've had a rethink regarding the ability to bypass the cache entirely. Remote 
files must be downloaded to somewhere before they may be used, so the cache is 
always needed for remote files. The "volatile_cache" option already exists to 
purge the cache when opkg exits and this may be used to keep long-term disk 
usage low.

Local files will not be copied to the cache by default, however as described in 
issue 139, a new option named "cache_local_files" will be added to specify that 
local files should be copied to the cache.

Therefore a "nocache" option will not be added at this stage.

Original comment by paul.betafive on 16 Sep 2014 at 2:58

• Changed state: WontFix