From 368aae9274c9b446ca94a8ee8f6cc229aa776d01 Mon Sep 17 00:00:00 2001
From: Stef Walter <stefw@redhat.com>
Date: Jul 17 2017 10:21:30 +0000
Subject: inventory: Add an inventory file that launches a docker container


This is one that pulls a docker container from a registry, and
launches it. We have to install python2 and friends for Ansible
to work inside the container.

Uses ansible_connection=docker

---

diff --git a/inventory/standard-inventory-docker b/inventory/standard-inventory-docker
new file mode 100755
index 0000000..8f3b39d
--- /dev/null
+++ b/inventory/standard-inventory-docker
@@ -0,0 +1,138 @@
+#!/usr/bin/env python
+
+import argparse
+import json
+import os
+import shutil
+import shlex
+import signal
+import socket
+import subprocess
+import sys
+import tempfile
+import time
+import traceback
+
+def main(argv):
+    parser = argparse.ArgumentParser(description="Inventory for a container image in a registry")
+    parser.add_argument("--list", action="store_true", help="Verbose output")
+    parser.add_argument('--host', help="Get host variables")
+    parser.add_argument("subjects", nargs="*", default=shlex.split(os.environ.get("TEST_SUBJECTS", "")))
+    opts = parser.parse_args()
+
+    try:
+        if opts.host:
+            name, data = host(opts.host)
+        else:
+            data = list(opts.subjects)
+        sys.stdout.write(json.dumps(data, indent=4, separators=(',', ': ')))
+    except RuntimeError, ex:
+        sys.stderr.write("{0}: {1}\n".format(os.path.basename(sys.argv[0]), str(ex)))
+        return 1
+
+    return 0
+
+def list(subjects):
+    hosts = [ ]
+    variables = { }
+    for subject in subjects:
+        if subject.startswith("docker:"):
+            image = subject[7:]
+            name, vars = host(image)
+            if vars:
+                hosts.append(name)
+                variables[name] = vars
+    return { "localhost": { "hosts": hosts, "vars": { } }, "subjects": { "hosts": hosts, "vars": { } }, "_meta": { "hostvars": variables } }
+
+def host(image):
+    null = open(os.devnull, 'w')
+
+    try:
+        tty = os.open("/dev/tty", os.O_WRONLY)
+        os.dup2(tty, 2)
+    except OSError:
+        tty = None
+        pass
+
+    directory = tempfile.mkdtemp(prefix="inventory-docker")
+    cidfile = os.path.join(directory, "cid")
+
+    sys.stderr.write("Launching Docker container for {0}\n".format(image))
+
+    # And launch the actual container
+    cmd = [
+        "/usr/bin/docker", "run", "--rm", "--detach", "--cidfile={0}".format(cidfile),
+        "--entrypoint=/bin/sh", image, "-c", "sleep 1000000"
+    ]
+
+    try:
+        subprocess.check_call(cmd, stdout=sys.stderr.fileno())
+    except subprocess.CalledProcessError, ex:
+        raise RuntimeError("Could not start container image: {0}".format(image))
+
+    # Read out the container environment variable
+    for x in range(1, 90):
+        if os.path.exists(cidfile):
+            break
+        time.sleep(1)
+    else:
+        raise RuntimeError("Could not find container file for launched container")
+
+    with open(cidfile, "r") as f:
+        name = f.read().strip()
+
+    # Now install the necessary stuff in the container :S
+    install = [
+        "/usr/bin/docker", "exec", "--user=root", name, "/usr/bin/yum", "-y", "install",
+        "python2", "python2-dnf", "libselinux-python"
+    ]
+    try:
+        subprocess.check_call(install, stdout=sys.stderr.fileno())
+    except subprocess.CalledProcessError, ex:
+        raise RuntimeError("Could not install Ansible dependencies in launched container")
+
+    # The variables
+    variables = {
+        "ansible_connection": "docker",
+    }
+
+    # Process of our parent
+    ppid = os.getppid()
+
+    child = os.fork()
+    if child:
+        return name, variables
+
+    # Daemonize and watch the processes
+    os.chdir("/")
+    os.setsid()
+    os.umask(0)
+
+    if tty is None:
+        tty = null.fileno()
+
+    # Duplicate standard input to standard output and standard error.
+    os.dup2(null.fileno(), 0)
+    os.dup2(tty, 1)
+    os.dup2(tty, 2)
+
+    # Now wait for the parent process to go away, then kill the VM
+    while True:
+        time.sleep(3)
+
+        try:
+            os.kill(ppid, 0)
+        except OSError:
+            break # Either of the processes no longer exist
+
+    # Kill the container
+    try:
+        subprocess.call(["/usr/bin/docker", "kill", name ])
+    except OSError:
+        pass
+
+    shutil.rmtree(directory)
+    sys.exit(0)
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv))