oscontainer: use extensions artifact, drop download-extensions

Use the tarball produced by `buildextend-extensions` as the source of
truth for extensions and drop `download-extensions` now that we no
longer need it.

src/cmd-upload-oscontainer

@@ -40,6 +40,14 @@ metapath = f"{latest_build_path}/meta.json"
 with open(metapath) as f:
     meta = json.load(f)
 
+# for backcompat, we auto-build extensions if they're missing
+if os.path.exists('src/config/extensions.yaml'):
+    if 'extensions' not in meta:
+        cmdlib.run_verbose(['coreos-assembler', 'buildextend-extensions'])
+        with open(metapath) as f:
+            meta = json.load(f)
+    assert 'extensions' in meta
+
 configdir = os.path.abspath('src/config')
 oscconfigpath = f'{configdir}/oscontainer.yaml'
 # XXX: fold oscontainer.yaml handling into oscontainer.py
@@ -51,15 +59,6 @@ if os.path.exists(oscconfigpath):
 if 'base' in configyaml:
     args.from_image = configyaml['base']
 
-extensions_src = 'src/config/extensions.yaml'
-extensions_destdir = None
-if os.path.exists(extensions_src):
-    extensions_destdir = 'tmp/extensions'
-    if os.path.exists(extensions_destdir):
-        shutil.rmtree(extensions_destdir)
-    os.mkdir(extensions_destdir)
-    cmdlib.run_verbose(['/usr/lib/coreos-assembler/download-extensions', extensions_destdir])
-
 print("Preparing to upload oscontainer for build: {}".format(latest_build))
 ostree_commit = meta['ostree-commit']
 
@@ -108,8 +107,6 @@ os.environ['REGISTRY_AUTH_FILE'] = authfile
 cosa_argv.extend(['/usr/lib/coreos-assembler/oscontainer.py', '--workdir=./tmp', 'build',  f"--from={args.from_image}"])
 for d in args.add_directory:
     cosa_argv.append(f"--add-directory={d}")
-if extensions_destdir is not None:
-    cosa_argv.append(f"--add-directory={extensions_destdir}")
 cosa_argv.append(f"--display-name={display_name}")
 subprocess.check_call(cosa_argv +
     [f'--digestfile={digestfile}',

src/oscontainer.py

@@ -169,12 +169,15 @@ def oscontainer_build(containers_storage, tmpdir, src, ref, image_name_and_tag,
                 f.write(nevra)
                 f.write('\n')
 
+        meta = {}
+        builddir = None
         if os.path.isfile('builds/builds.json'):
             with open('builds/builds.json') as fb:
                 builds = json.load(fb)['builds']
             latest_build = builds[0]['id']
             arch = cmdlib.get_basearch()
-            metapath = f"builds/{latest_build}/{arch}/meta.json"
+            builddir = f"builds/{latest_build}/{arch}"
+            metapath = f"{builddir}/meta.json"
             with open(metapath) as f:
                 meta = json.load(f)
             rhcos_commit = meta['coreos-assembler.container-config-git']['commit']
@@ -184,6 +187,12 @@ def oscontainer_build(containers_storage, tmpdir, src, ref, image_name_and_tag,
                 config += ['-l', f"com.coreos.coreos-assembler-commit={cosa_commit}"]
             config += ['-l', f"com.coreos.redhat-coreos-commit={rhcos_commit}"]
 
+        if 'extensions' in meta:
+            tarball = os.path.abspath(os.path.join(builddir, meta['extensions']['path']))
+            dest_dir = os.path.join(mnt, 'extensions')
+            os.makedirs(dest_dir, exist_ok=True)
+            run_verbose(["tar", "-xf", tarball], cwd=dest_dir)
+
         if display_name is not None:
             config += ['-l', 'io.openshift.build.version-display-names=machine-os=' + display_name,
                        '-l', 'io.openshift.build.versions=machine-os=' + ostree_version]