runners: create fake machine id when needed

Create fake machine before executing the runner command to
avoid the "Failed to resolve specifiers in '/var/log/journal/%m'"
errors.

osbuild/util/runners.py

@@ -1,8 +1,10 @@
 import os.path
+import pathlib
 import platform
 import shutil
 import subprocess
 import sys
+from contextlib import contextmanager
 
 
 def ldconfig(*dirs):
@@ -31,6 +33,29 @@ def sysusers():
         sys.exit(1)
 
 
+@contextmanager
+def create_machine_id_if_needed(tree="", keep_empty=False):
+    """Create a machine-id with a fake machine id if it does not exist.
+       The machine-id file will be delete at context exit unless specified
+       with 'keep_empty' variable. In that case an empty machine-id will
+       be kept.
+    """
+    path = pathlib.Path(f"{tree}/etc/machine-id")
+    try:
+        if not path.exists():
+            path.parent.mkdir(mode=0o755, exist_ok=True)
+            with path.open(mode="w", encoding="utf8") as f:
+                # create a fake machine ID to improve reproducibility
+                f.write("ffffffffffffffffffffffffffffffff\n")
+                path.chmod(0o444)
+        yield
+    finally:
+        path.unlink()
+        if keep_empty:
+            path.touch()
+            path.chmod(0o444)
+
+
 def tmpfiles():
     # Allow systemd-tmpfiles to return non-0. Some packages want to create
     # directories owned by users that are not set up with systemd-sysusers.

runners/org.osbuild.centos9

@@ -10,9 +10,9 @@ if __name__ == "__main__":
     with api.exception_handler():
         runners.ldconfig()
         runners.sysusers()
+        with runners.create_machine_id_if_needed():
             runners.tmpfiles()
             runners.nsswitch()
-
             r = subprocess.run(sys.argv[1:], check=False)
 
         sys.exit(r.returncode)

runners/org.osbuild.fedora30

@@ -10,9 +10,9 @@ if __name__ == "__main__":
     with api.exception_handler():
         runners.ldconfig()
         runners.sysusers()
+        with runners.create_machine_id_if_needed():
             runners.tmpfiles()
             runners.nsswitch()
-
             r = subprocess.run(sys.argv[1:], check=False)
 
         sys.exit(r.returncode)

runners/org.osbuild.fedora38

@@ -10,9 +10,10 @@ if __name__ == "__main__":
     with api.exception_handler():
         runners.ldconfig()
         runners.sysusers()
+        with runners.create_machine_id_if_needed():
             runners.tmpfiles()
             runners.nsswitch()
             runners.sequoia()
-
             r = subprocess.run(sys.argv[1:], check=False)
+
         sys.exit(r.returncode)

runners/org.osbuild.rhel81

@@ -35,10 +35,11 @@ if __name__ == "__main__":
     with api.exception_handler():
         runners.ldconfig()
         runners.sysusers()
+        with runners.create_machine_id_if_needed():
             runners.tmpfiles()
             runners.nsswitch()
             os_release()
             runners.python_alternatives()
-
             r = subprocess.run(sys.argv[1:], check=False)
+
         sys.exit(r.returncode)

runners/org.osbuild.rhel82

@@ -10,12 +10,11 @@ if __name__ == "__main__":
     with api.exception_handler():
         runners.ldconfig()
         runners.sysusers()
+        with runners.create_machine_id_if_needed():
             runners.tmpfiles()
             runners.nsswitch()
             runners.python_alternatives()
-
             env = runners.quirks()
-
             r = subprocess.run(sys.argv[1:], env=env, check=False)
 
         sys.exit(r.returncode)

stages/org.osbuild.rpm

@@ -35,7 +35,6 @@ This stage will return the following metadata via the osbuild API:
 import contextlib
 import json
 import os
-import pathlib
 import subprocess
 import sys
 import tempfile
@@ -43,6 +42,7 @@ from operator import itemgetter
 
 from osbuild import api
 from osbuild.util.mnt import mount
+from osbuild.util.runners import create_machine_id_if_needed
 
 SCHEMA = """
 "additionalProperties": false,
@@ -263,21 +263,6 @@ def parse_input(inputs):
     return path, files
 
 
-def create_machine_id_if_needed(tree):
-    """Create a machine-id with a fake machine id if it does not exist"""
-    path = f"{tree}/etc/machine-id"
-    if os.path.exists(path):
-        return False
-
-    os.makedirs(f"{tree}/etc", exist_ok=True)
-    with open(path, "w", encoding="utf8") as f:
-        # create a fake machine ID to improve reproducibility
-        f.write("ffffffffffffffffffffffffffffffff\n")
-        os.fchmod(f.fileno(), 0o400)
-
-    return True
-
-
 # pylint: disable=too-many-branches
 def main(tree, inputs, options):
     pkgpath, packages = parse_input(inputs)
@@ -322,8 +307,7 @@ def main(tree, inputs, options):
 
     os.symlink("/proc/self/fd", f"{tree}/dev/fd")
 
-    machine_id_created = create_machine_id_if_needed(tree)
+    with create_machine_id_if_needed(tree, keep_empty=True):
-
         ostree_booted = None
         if options.get("ostree_booted", False):
             os.makedirs(f"{tree}/run", exist_ok=True)
@@ -379,13 +363,6 @@ def main(tree, inputs, options):
             enable_dracut(masked_files)
             remove_unowned_etc_kernel(tree, rpm_args)
 
-    # remove temporary machine ID if it was created by us
-    if machine_id_created:
-        print("deleting the fake machine id")
-        machine_id_file = pathlib.Path(f"{tree}/etc/machine-id")
-        machine_id_file.unlink()
-        machine_id_file.touch(mode=0o444)
-
     if ostree_booted:
         os.unlink(ostree_booted)