implement basic debspawn backend

3 files changed, 70 insertions, 2 deletions

diff --git a/TODO.md b/TODO.md
deleted file mode 100644
index c85bb89..0000000
--- a/TODO.md
+++ /dev/null
@@ -1,2 +0,0 @@
-* There should be a backend supporting a container thingy (e.g. `debspawn`,
-  `debocker`, `whalebuilder`).
diff --git a/mdbp/debspawn.py b/mdbp/debspawn.py
new file mode 100755
index 0000000..e98605c
--- /dev/null
+++ b/mdbp/debspawn.py
@@ -0,0 +1,69 @@
+#!/usr/bin/python3
+# SPDX-License-Identifier: MIT
+"""mdbp backend using debspawn"""
+
+import argparse
+import itertools
+import os
+import pathlib
+import subprocess
+import sys
+
+from .common import buildjson, clean_dir, compute_env, get_dsc, make_option
+
+def main() -> None:
+    """Entry point for mdbp-debspawn backend"""
+    parser = argparse.ArgumentParser()
+    parser.add_argument("buildjson", type=buildjson)
+    args = parser.parse_args()
+    build = args.buildjson
+
+    if "sourcename" in build["input"]:
+        raise ValueError("building a source package by name is not supported")
+    if "bd-uninstallable-explainer" in build:
+        raise ValueError("bd-uninstallable-explainer %r not supported" %
+                         build["bd-uinstallable-explainer"])
+    if build.get("buildpath"):
+        raise ValueError("buildpath not supported")
+    if build.get("hostarch") not in (None, build.get("buildarch")):
+        raise ValueError("cross building is not supported")
+    if build.get("lintian", {}).get("run", False) and \
+       build["lintian"].get("options"):
+        raise ValueError("setting lintian options is not supported")
+    if build.get("network") == "disable":
+        raise ValueError("disabling network is not supported")
+
+    env = compute_env(build)
+    if build.get("profiles"):
+        env["DEB_BUILD_PROFILES"] = " ".join(build["profiles"])
+    enablelog = build["output"].get("log", True)
+
+    cmd = [
+        *(["sudo", "--"] if os.getuid() != 0 else ()),
+        "debspawn", "build", "--no-buildlog",
+        *make_option("--arch", build.get("buildarch")),
+        "--only",
+        dict(
+            any="arch",
+            all="indep",
+            binary="binary",
+        )[build.get("type", "binary")],
+        "--results-dir", build["output"]["directory"],
+        *(["--run-lintian"] if build.get("lintian", {}).get("run", False)
+          else ()),
+        *itertools.chain.from_iterable(
+            ("--setenv", "%s=%s" % item) for item in env.items()),
+        build["distribution"],
+    ]
+    with get_dsc(build) as dscpath:
+        ret = subprocess.call([*cmd, str(dscpath)],
+                              stdout=None if enablelog else subprocess.DEVNULL,
+                              stderr=subprocess.STDOUT if enablelog
+                                     else subprocess.DEVNULL,
+                              )
+    clean_dir(pathlib.Path(build["output"]["directory"]),
+              build["output"].get("artifacts", ["*"]))
+    sys.exit(ret)
+
+if __name__ == "__main__":
+    main()
diff --git a/setup.py b/setup.py
index ba840d7..d84d0bc 100755
--- a/setup.py
+++ b/setup.py
@@ -20,6 +20,7 @@ setup(name="mdbp",
       ],
       entry_points=dict(
           console_scripts=[
+              "mdbp-debspawn=mdbp.debspawn:main",
               "mdbp-mmdebstrap=mdbp.mmdebstrap:main",
               "mdbp-pbuilder=mdbp.pbuilder:main",
               "mdbp-sbuild=mdbp.sbuild:main",