Pick up buildah base build arguments for container builds

Ensure that buildah is called for kubevirt with the same base arguments
like for the oscontainer.

Signed-off-by: Roman Mohr <[email protected]>

src/cosalib/buildah.py

@@ -0,0 +1,16 @@
+import os
+
+# https://access.redhat.com/documentation/en-us/openshift_container_platform/4.1/html/builds/custom-builds-buildah
+NESTED_BUILD_ARGS = ['--storage-driver', 'vfs']
+
+
+def buildah_base_args(containers_storage=None):
+    buildah_base_argv = ['buildah']
+    if containers_storage is not None:
+        buildah_base_argv.append(f"--root={containers_storage}")
+    if os.environ.get('container') is not None:
+        print("Using nested container mode due to container environment variable")
+        buildah_base_argv.extend(NESTED_BUILD_ARGS)
+    else:
+        print("Skipping nested container mode")
+    return buildah_base_argv

src/cosalib/kubevirt.py

@@ -3,7 +3,11 @@
 import logging as log
 
 from cosalib.cmdlib import (
-    run_verbose
+    run_verbose,
+)
+
+from cosalib.buildah import (
+    buildah_base_args
 )
 
 from cosalib.qemuvariants import QemuVariantImage
@@ -26,12 +30,13 @@ def write_oci(self, image_name):
         """
         Take the qcow2 base image and convert it to an oci-archive.
         """
+        buildah_base_argv = buildah_base_args()
         final_img = os.path.join(os.path.abspath(self.build_dir),
                                  self.image_name)
-        buildah_img = run_verbose(["buildah", "from", "scratch"], stdout=subprocess.PIPE).stdout.decode("utf-8").strip()
-        run_verbose(["buildah", "add", "--chmod", "0555", buildah_img, image_name, "/disk/coreos.img"])
-        digest = run_verbose(["buildah", "commit", buildah_img], stdout=subprocess.PIPE).stdout.decode("utf-8").strip()
-        run_verbose(["buildah", "push", "--format", "oci", digest, f"oci-archive:{final_img}"])
+        buildah_img = run_verbose_collect_stdout(buildah_base_argv + ["from", "scratch"])
+        run_verbose(buildah_base_argv + ["add", "--chmod", "0555", buildah_img, image_name, "/disk/coreos.img"])
+        digest = run_verbose_collect_stdout(buildah_base_argv + ["commit", buildah_img])
+        run_verbose(buildah_base_argv + ["push", "--format", "oci", digest, f"oci-archive:{final_img}"])
 
 
 def kubevirt_run_ore(build, args):
@@ -83,3 +88,7 @@ def get_kubevirt_variant(variant, parser, kwargs={}):
         arch=parser.arch,
         compress=parser.compress,
         **kwargs)
+
+
+def run_verbose_collect_stdout(args):
+    return run_verbose(args, stdout=subprocess.PIPE).stdout.decode("utf-8").strip()

src/oscontainer.py

@@ -20,12 +20,12 @@
 import shutil
 import subprocess
 from cosalib import cmdlib
+from cosalib.buildah import (
+    buildah_base_args
+)
 
 OSCONTAINER_COMMIT_LABEL = 'com.coreos.ostree-commit'
 
-# https://access.redhat.com/documentation/en-us/openshift_container_platform/4.1/html/builds/custom-builds-buildah
-NESTED_BUILD_ARGS = ['--storage-driver', 'vfs']
-
 
 def run_get_json(args):
     return json.loads(subprocess.check_output(args))
@@ -113,14 +113,7 @@ def oscontainer_build(containers_storage, tmpdir, src, ref, image_name_and_tag,
     else:
         ostree_version = None
 
-    buildah_base_argv = ['buildah']
-    if containers_storage is not None:
-        buildah_base_argv.append(f"--root={containers_storage}")
-        if os.environ.get('container') is not None:
-            print("Using nested container mode due to container environment variable")
-            buildah_base_argv.extend(NESTED_BUILD_ARGS)
-        else:
-            print("Skipping nested container mode")
+    buildah_base_argv = buildah_base_args(containers_storage)
 
     # In general, we just stick with the default tmpdir set up. But if a
     # workdir is provided, then we want to be sure that all the heavy I/O work