sbuild: generalize addition of hook commands

1 files changed, 25 insertions, 5 deletions

diff --git a/mdbp/sbuild.py b/mdbp/sbuild.py
index da0ac4b..8330e6e 100644
--- a/mdbp/sbuild.py
+++ b/mdbp/sbuild.py
@@ -40,6 +40,20 @@ def perl_conf(conf: typing.Dict[str, PerlValue]) -> str:
     return "".join("$%s=%s;\n" % (key, perl_repr(value))
                    for key, value in conf.items()) + "1;\n"
 
+
+def add_external_command(
+    conf: typing.Dict[str, PerlValue], stage: str, command: str
+) -> None:
+    """Modify the given conf object to add the given command on the given
+    external_commands stage.
+    """
+    extcomm = conf.setdefault("external_commands", {})
+    assert isinstance(extcomm, dict)
+    comms = extcomm.setdefault(stage, [])
+    assert isinstance(comms, list)
+    comms.append(command)
+
+
 def main() -> None:
     """Entry point for mdbp-sbuild backend"""
     parser = argparse.ArgumentParser()
@@ -78,7 +92,7 @@ def main() -> None:
         run_lintian=bool(build.get("lintian", {}).get("run")),
         extra_repositories=build.get("extra_repositories", []),
         build_environment=compute_env(build),
-        external_commands={})
+    )
     with contextlib.suppress(KeyError):
         sbc["lintian_opts"] = build["lintian"]["options"]
     with contextlib.suppress(KeyError):
@@ -90,10 +104,16 @@ def main() -> None:
     with contextlib.suppress(KeyError):
         sbc["build_path"] = build["build_path"]
     if build.get("network") == "try-disable":
-        sbc["external_commands"]["starting-build-commands"] = \
-                ["mv /etc/resolv.conf /etc/resolv.conf.disabled"]
-        sbc["external_commands"]["finished-build-commands"] = \
-                ["mv /etc/resolv.conf.disabled /etc/resolv.conf"]
+        add_external_command(
+            sbc,
+            "starting-build-commands",
+            "mv /etc/resolv.conf /etc/resolv.conf.disabled",
+        )
+        add_external_command(
+            sbc,
+            "finished-build-commands",
+            "mv /etc/resolv.conf.disabled /etc/resolv.conf",
+        )
 
     with contextlib.ExitStack() as stack:
         sbuildconf = stack.enter_context(temporary_static_file(perl_conf(sbc)))