[libvirt] [dockerfiles PATCH 2/4] refresh: Add Python implementation

[Andrea Bolognani]

This behaves mostly like a drop-in replacement for the
original shell script, with a few differences:

  * the script figures out which Dockerfiles should be
    generated by looking at the contents of the repository
    rather than by asking lcitool. This makes it possible to
    skip generation of Dockerfiles that lcitool knows about
    without having to implement custom filtering logic in the
    script;

  * pointing the script to the libvirt-jenkins-ci repository
    is no longer mandatory, since it implements some very
    simple detection logic of its own;

  * the name of the Dockerfile being refreshed is printed on
    standard output, giving the user some indication that
    progress is being made.

Moving to Python also makes it easier to extend the script,
which is something that we'll take advantage of in a second.

Signed-off-by: Andrea Bolognani <abologna at redhat.com>
---
 refresh | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100755 refresh

diff --git a/refresh b/refresh
new file mode 100755
index 0000000..5f7c41c
--- /dev/null
+++ b/refresh
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+
+# refresh - Refresh Dockerfiles using lcitool
+# Copyright (C) 2019  Andrea Bolognani <abologna at redhat.com>
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+# Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import pathlib
+import subprocess
+import sys
+
+
+class Error(Exception):
+
+    def __init__(self, message):
+        super(Error, self).__init__()
+        self.message = message
+
+
+class MoveAlongException(Exception):
+    pass
+
+
+class Dockerfile:
+
+    PREFIX = "buildenv-"
+    SUFFIX = ".Dockerfile"
+
+    def __init__(self, path):
+
+        # Files that don't end with the expected suffix can be safely
+        # ignores
+        if not path.suffix == Dockerfile.SUFFIX:
+            raise MoveAlongException()
+
+        # Files that don't follow the expected format should be reported
+        if not path.stem.startswith(Dockerfile.PREFIX):
+            raise Error("Invalid name '{}'".format(path.stem))
+
+        self.path = path
+        self.os = path.stem[len(Dockerfile.PREFIX):]
+
+        # Fedora Rawhide is special in that we use it to perform MinGW
+        # builds, so we need to add the corresponding projects
+        if self.os == "fedora-rawhide":
+            self.projects = "libvirt,libvirt+mingw*"
+        else:
+            self.projects = "libvirt"
+
+    def refresh(self, lcitool):
+
+        args = [
+            lcitool,
+            "dockerfile",
+            "libvirt-" + self.os,
+            self.projects,
+        ]
+
+        rc = subprocess.run(args, capture_output=True)
+
+        if rc.returncode != 0:
+            raise Error("lcitool failed: {}".format(rc.stderr.decode()))
+
+        with self.path.open('w') as f:
+            print(rc.stdout.decode().strip(), file=f)
+
+
+class Application:
+
+    def __init__(self):
+
+        # Find the directory the script lives in
+        me = pathlib.Path(sys.argv[0]).resolve()
+        self.here = me.parent
+
+        # If an argument has been provided, we're going to consider it as
+        # the path to a clone of libvirt-jenkins-ci.git; otherwise, we're
+        # going to assume such a clone exists besides the clone of
+        # libvirt-dockerfiles.git we're running the script from
+        if len(sys.argv) >= 2:
+            ci_repo = pathlib.Path(sys.argv[1]).resolve()
+        else:
+            ci_repo = self.here.parent.joinpath("libvirt-jenkins-ci")
+
+        self.lcitool = ci_repo.joinpath("guests").joinpath("lcitool")
+
+        if not self.lcitool.exists():
+            raise Error("{} does not exist".format(self.lcitool))
+
+    def run(self):
+
+        for item in self.here.iterdir():
+            try:
+                dockerfile = Dockerfile(item)
+            except MoveAlongException:
+                continue
+
+            print(item.stem + item.suffix)
+            dockerfile.refresh(self.lcitool)
+
+
+if __name__ == "__main__":
+    try:
+        Application().run()
+    except Error as err:
+        sys.stderr.write("{}: {}\n".format(sys.argv[0], err.message))
+        sys.exit(1)
-- 
2.20.1