Initial commit.

modoboa_installer/utils.py

@@ -0,0 +1,137 @@
+"""Utility functions."""
+
+import contextlib
+import datetime
+import os
+import string
+import subprocess
+import sys
+
+
+ENV = {}
+BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE = range(8)
+
+
+class FatalError(Exception):
+
+    """A simple exception."""
+
+    pass
+
+
+def user_input(message):
+    """Ask something to the user."""
+    try:
+        from builtins import input
+    except ImportError:
+        answer = raw_input(message)
+    else:
+        answer = input(message)
+    return answer
+
+
+def exec_cmd(cmd, sudo_user=None, pinput=None, **kwargs):
+    """Execute a shell command.
+    Run a command using the current user. Set :keyword:`sudo_user` if
+    you need different privileges.
+    :param str cmd: the command to execute
+    :param str sudo_user: a valid system username
+    :param str pinput: data to send to process's stdin
+    :rtype: tuple
+    :return: return code, command output
+    """
+    sudo_user = ENV.get("sudo_user", sudo_user)
+    if sudo_user is not None:
+        cmd = "sudo -u %s %s" % (sudo_user, cmd)
+    if "shell" not in kwargs:
+        kwargs["shell"] = True
+    if pinput is not None:
+        kwargs["stdin"] = subprocess.PIPE
+    capture_output = False
+    if "capture_output" in kwargs:
+        capture_output = kwargs.pop("capture_output")
+    elif not ENV.get("debug"):
+        capture_output = True
+    if capture_output:
+        kwargs.update(stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    output = None
+    process = subprocess.Popen(cmd, **kwargs)
+    if pinput or capture_output:
+        c_args = [pinput] if pinput is not None else []
+        output = process.communicate(*c_args)[0]
+    else:
+        process.wait()
+    return process.returncode, output
+
+
+def install_system_package(name, update=False):
+    """Install a package system-wide."""
+    if update:
+        exec_cmd("apt-get update --quiet")
+    exec_cmd("apt-get install --quiet --assume-yes {}".format(name))
+
+
+def install_system_packages(names):
+    """Install some packages system-wide."""
+    exec_cmd("apt-get install --quiet --assume-yes {}".format(" ".join(names)))
+
+
+def mkdir(path, mode, uid, gid):
+    """Create a directory."""
+    if not os.path.exists(path):
+        os.mkdir(path, mode)
+    else:
+        os.chmod(path, mode)
+    os.chown(path, uid, gid)
+
+
+@contextlib.contextmanager
+def settings(**kwargs):
+    """Context manager to declare temporary settings."""
+    for key, value in kwargs.items():
+        ENV[key] = value
+    yield
+    for key in kwargs.keys():
+        del ENV[key]
+
+
+class ConfigFileTemplate(string.Template):
+
+    """Custom class for configuration files."""
+
+    delimiter = "%"
+
+
+def copy_from_template(template, dest, context):
+    """Create and copy a configuration file from a template."""
+    with open(template) as fp:
+        buf = fp.read()
+    with open(dest, "w") as fp:
+        now = datetime.datetime.now()
+        fp.write(
+            "# This file was automatically installed on {}\n"
+            .format(now.isoformat()))
+        fp.write(ConfigFileTemplate(buf).substitute(context))
+
+
+def has_colours(stream):
+    """Check if terminal supports colors."""
+    if not hasattr(stream, "isatty"):
+        return False
+    if not stream.isatty():
+        return False  # auto color only on TTYs
+    try:
+        import curses
+        curses.setupterm()
+        return curses.tigetnum("colors") > 2
+    except:
+        # guess false in case of error
+        return False
+has_colours = has_colours(sys.stdout)
+
+
+def printcolor(message, color):
+    """Print a message using a green color."""
+    if has_colours:
+        message = "\x1b[1;{}m{}\x1b[0m".format(30 + color, message)
+    print(message)