Merge lp:~zyga/snapcraft/fix-1486659 into lp:~snappy-dev/snapcraft/core

[Zygmunt Krynicki]

Fix numerous issues in snapcraft run

This branch fixes numerous related issues in snapcraft run. I would recommend to read the flow of commits one-by-one, in order.

[Michael Vogt (mvo)]

Looks good, thanks!

review: Approve

=== modified file 'snapcraft/cmds.py'
--- snapcraft/cmds.py	2015-08-26 09:11:57 +0000
+++ snapcraft/cmds.py	2015-08-26 10:29:20 +0000
@@ -158,7 +158,74 @@
     common.run(['snappy', 'build', common.get_snapdir()])
 
 
+def _find_latest_private_key():
+    """
+    Find the latest private key in ~/.ssh.
+
+    :returns:
+        Path of the most-recently-modified private SSH key
+    :raises LookupError:
+        If no such key was found.
+
+    This function tries to mimic the logic found in ``ubuntu-device-flash``. It
+    will look for the most recently modified private key in the users' SSH
+    configuration directory.
+    """
+    candidates = []
+    ssh_dir = os.path.expanduser('~/.ssh/')
+    for filename in os.listdir(ssh_dir):
+        # Skip public keys, we want the private key
+        if filename.endswith('.pub'):
+            continue
+        ssh_key = os.path.join(ssh_dir, filename)
+        # Skip non-files
+        if not os.path.isfile(ssh_key):
+            continue
+        # Ensure that it is a real ssh key
+        with open(ssh_key, 'rb') as stream:
+            if stream.readline() != b'-----BEGIN RSA PRIVATE KEY-----\n':
+                continue
+        candidates.append(ssh_key)
+    # Sort the keys by modification time, pick the most recent key
+    candidates.sort(key=lambda f: os.stat(f).st_mtime, reverse=True)
+    logger.debug("Available ssh public keys: %r", candidates)
+    if not candidates:
+        raise LookupError("Unable to find any private ssh key")
+    return candidates[0]
+
+
 def run(args):
+    # Find the ssh key that ubuntu-device-flash would use so that we can use it
+    # ourselves as well. This may not be the default key that the user has
+    # configured.
+    # See: https://bugs.launchpad.net/snapcraft/+bug/1486659
+    try:
+        ssh_key = _find_latest_private_key()
+    except LookupError:
+        logger.error("You need to have an SSH key to use this command")
+        logger.error("Please generate one with ssh-keygen(1)")
+        return 1
+    else:
+        logger.info("Using the following ssh key: %s", ssh_key)
+
+    # Find available *.snap files to copy into the test VM
+    snap_dir = os.path.join(os.getcwd())
+    # copy the snap with the largest version number into the test VM
+    snaps = glob.glob(snap_dir + "/*.snap")
+    snaps.sort()
+    if not snaps:
+        logger.error("There are no .snap files ready")
+        logger.error("Perhaps you forgot to run 'snapcraft assemble'")
+        return 1
+
+    def _call(args, **kwargs):
+        logger.info('Running: %s', ' '.join(shlex.quote(arg) for arg in args))
+        return subprocess.call(args, **kwargs)
+
+    def _check_call(args, **kwargs):
+        logger.info('Running: %s', ' '.join(shlex.quote(arg) for arg in args))
+        return subprocess.check_call(args, **kwargs)
+
     qemudir = os.path.join(os.getcwd(), "image")
     qemu_img = os.path.join(qemudir, "15.04.img")
     if not os.path.exists(qemu_img):
@@ -177,29 +244,37 @@
             stdin=subprocess.PIPE)
         n = tempfile.NamedTemporaryFile()
         ssh_opts = [
+            # We want to login with the specified ssh identity (key)
+            '-i', ssh_key,
+            # We don't want strict host checking because it's a new VM with a
+            # random key each time.
             "-oStrictHostKeyChecking=no",
-            "-oUserKnownHostsFile=%s" % n.name
+            # We don't want to pollute the known_hosts file with new entries
+            # all the time so let's use a temporary file for that
+            "-oUserKnownHostsFile=%s" % n.name,
+            # Don't try keyboard interactive authentication, we're expecting to
+            # login via the key and if that doesn't work then everything else
+            # will fail anyway.
+            "-oKbdInteractiveAuthentication=no",
         ]
         while True:
-            ret_code = subprocess.call(
+            ret_code = _call(
                 ["ssh"] + ssh_opts +
                 ["ubuntu@localhost", "-p", "8022", "true"])
             if ret_code == 0:
                 break
             print("Waiting for device")
             time.sleep(1)
-        snap_dir = os.path.join(os.getcwd(), "snap")
-        # copy the snap
-        snaps = glob.glob(snap_dir + "/*.snap")
-        subprocess.call(
+        # copy the most recent snap into the test VM
+        _check_call(
             ["scp"] + ssh_opts + [
-                "-P", "8022", "-r"] + snaps + ["ubuntu@localhost:~/"])
+                "-P", "8022", snaps[-1], "ubuntu@localhost:~/"])
         # install the snap
-        ret_code = subprocess.call(
+        _check_call(
             ["ssh"] + ssh_opts +
             ["ubuntu@localhost", "-p", "8022", "sudo snappy install  *.snap"])
         # "login"
-        subprocess.call(
+        _check_call(
             ["ssh"] + ssh_opts + ["-p", "8022", "ubuntu@localhost"],
             preexec_fn=os.setsid)
     finally: