Add relevant ccache env when building package

scale_build/packages/build.py

@@ -53,11 +53,13 @@ class BuildPackageMixin:
         self._build_impl()
 
     def _get_build_env(self):
-        return {
+        env = {
             **os.environ,
             **APT_ENV,
             **self.env,
         }
+        env.update(self.ccache_env(env))
+        return env
 
     def _build_impl(self):
         shutil.copytree(self.source_path, self.source_in_chroot, dirs_exist_ok=True, symlinks=True)

scale_build/packages/ccache.py

@@ -18,3 +18,13 @@ class CCacheMixin:
     @property
     def ccache_in_chroot(self) -> str:
         return '/root/.ccache'
+
+    def ccache_env(self, existing_env: dict) -> dict:
+        if not self.ccache_enabled:
+            return {}
+
+        env = {'CCACHE_DIR': self.ccache_in_chroot}
+        if self.CCACHE_PATH not in existing_env['PATH'].split(':'):
+            env['PATH'] = f'{self.CCACHE_PATH}:{existing_env["PATH"]}'
+
+        return env