[pacman-dev] [PATCH 0/4] hooks

[Allan McRae]

Firstly, WOO!

On 04/07/15 19:59, Andrew Gregory wrote:
> = TODO =
>  * documentation
>  * run PreTransaction hooks *after* conflict checks
>  * hook/trigger validation
>  * masking hooks with an empty file or symlink to /dev/null
>  * tests
> 
> = Hook Directories =
> 
> ALPM handles keep a list of hook directories to scan.  Initially, this list is
> populated with a single directory: /usr/share/alpm/hooks/.  This directory is
> intended for packages to be able to place hooks in a front-end agnostic manner.
> Front-ends may specify any number of additional directories to search, with
> later directories overriding earlier ones.  Front-ends can disable hooks
> altogether by setting an empty list.
> 
> = Parsing Hooks =
> 
> Configured directories are scanned for files matching '*.hook'.  Hook files
> must be in pacman-style INI format with the following available options:
> 
>  [Trigger] (multiple Trigger sections allowed)
>  Operation = Sync|Remove (Required)
>  Type = File|Package (Required)
>  Target = <Path|PkgName> (Required, multiple allowed)
>  
>  [Action] (only one Action section allowed)
>  When = PreTransaction|PostTransaction (Required)
>  Exec = <Command> (Required)
>  Depends = <PkgName> (Optional)
>  AbortOnFail (Optional, PreTransaction only)

Looks good to me.

Idea: Do we want to add a field that provides suggest text to display
while it is running.  I assume pacman will state what hooks it is
running and something better than "Running foo.hook..." would be useful.

> Unlike pacman.conf multiple values are *not* allowed on a single line.

Is there a reason for this?  Are they allowed for Target?

> Exec is currently limited to the path of the executable to run, arguments are
> not allowed.  This is intended to be a temporary limitation until I decide the
> best way to go about splitting the arguments, which depends in part on whether
> we want to try to provide hooks with the packages/files that triggered them.

Fair enough - updating caches is the big slowdown during Arch updates.
This will cover that.

But I'd really like at least the filename to be used.  e.g. for info
files.  Is there a current usage case for package name?

> Targets are matched the same as IgnorePkg in pacman.conf, meaning multiple
> targets can be specified and targets can be negated with a leading '!'.

Great

> If multiple Trigger sections are specified the hook will run if any of them
> match the transaction.
> 
> = Running Hooks =
> 
> Hooks are not cached after running.  Directories are rescanned and hooks
> reloaded each time.  This is to make sure that any hooks added/removed during
> a transaction are appropriately accounted for.

So load hooks -> PreTransaction, do stuff, load hooks ->
PostTransaction?  (aside: do we currently save a list of all files
changed? I have a feeling we do during conflict checking)

> Hooks are run exactly the same as install scriptlets (chroot, output passed to
> the front-end, etc.).
> 
> They do *not* have access to which package/file triggered the hook.
> 
> For the time being, run order is officially undefined.

Fine.


I'm happy to commit the first two patches now if that would help.  I'll
take a decent look that the second two later.


WOO!
Allan