Add support for ccache

This is set up so that each individual project repository has its own
ccache, all under one defined directory.

The top-level ccache directory is added as the setting
'compiler-cache-dir', and defaults to $cachedir/ccache.

When a build is performed, this will bind-mount a project's ccache into
the /tmp/ccache of the staging-area and set up the environment variables
so that ccache will be used (if appropriate executables are installed
to /usr/lib/ccache in the staging-area).

In addition, this removes code for ccache-remotedir, as it is unrelated
to this implementation of ccache.

Reviewed-by: Jannis Pohlmann <jannis.pohlmann@codethink.co.uk>
Reviewed-by: Lars Wirzenius <lars.wirzenius@codethink.co.uk>

1 files changed, 5 insertions, 14 deletions

diff --git a/morphlib/app.py b/morphlib/app.py
index d154f8b9..a13d26a1 100755
--- a/morphlib/app.py
+++ b/morphlib/app.py
@@ -43,8 +43,6 @@ defaults = {
     'max-jobs': morphlib.util.make_concurrency(),
     'prefix': '/usr',
     'toolchain-target': '%s-baserock-linux-gnu' % os.uname()[4],
-    'ccache-remotedir': '',
-    'ccache-remotenlevels': 2,
     'build-ref-prefix': 'baserock/builds'
 }
 
@@ -61,6 +59,11 @@ class Morph(cliapp.Application):
                              'cache git repositories and build results in DIR',
                              metavar='DIR',
                              default=defaults['cachedir'])
+        self.settings.string(['compiler-cache-dir'],
+                             'cache compiled objects in CCDIR/REPO_NAME',
+                             metavar='CCDIR',
+                             default=os.path.join(self.settings['cachedir'],
+                                                  'ccache'))
         self.settings.string(['build-ref-prefix'],
                              'Prefix to use for temporary build refs',
                              metavar='PREFIX',
@@ -109,18 +112,6 @@ class Morph(cliapp.Application):
                               'DANGEROUS and will install stuff on your '
                               'system',
                               group=group_build)
-        self.settings.string(['ccache-remotedir'],
-                             'allow ccache to download objects from REMOTEDIR '
-                             'if they are not cached locally',
-                             metavar='REMOTEDIR',
-                             default=defaults['ccache-remotedir'],
-                             group=group_build)
-        self.settings.integer(['ccache-remotenlevels'],
-                              'assume ccache directory objects are split into '
-                              'NLEVELS levels of subdirectories',
-                              metavar='NLEVELS',
-                              default=defaults['ccache-remotenlevels'],
-                              group=group_build)
         self.settings.boolean(['keep-path'],
                               'do not touch the PATH environment variable',
                               group=group_build)