Merge pull request #3940 from hnakamur/hostname_module

Add a hostname module, which sets system's hostname.

library/system/hostname

+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# (c) 2013, Hiroaki Nakamura <hnakamur@gmail.com>
+#
+# This file is part of Ansible
+#
+# Ansible 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 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible 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 Ansible.  If not, see <http://www.gnu.org/licenses/>.
+
+DOCUMENTATION = '''
+---
+module: hostname
+author: Hiroaki Nakamura
+version_added: "1.3"
+short_description: Manage hostname
+requirements: [ hostname ]
+description:
+    - Set system's hostname
+    - Currently implemented on only Debian, Ubuntu, RedHat and CentOS.
+options:
+    name:
+        required: true
+        description:
+            - Name of the host
+'''
+
+EXAMPLES = '''
+- hostname: name=web01
+'''
+
+class UnimplementedStrategy(object):
+    def __init__(self, module):
+        self.module = module
+
+    def get_current_hostname(self):
+        self.unimplemented_error()
+
+    def set_current_hostname(self, name):
+        self.unimplemented_error()
+
+    def get_permanent_hostname(self):
+        self.unimplemented_error()
+
+    def set_permanent_hostname(self, name):
+        self.unimplemented_error()
+
+    def unimplemented_error(self):
+        platform = get_platform()
+        distribution = get_distribution()
+        if distribution is not None:
+            msg_platform = '%s (%s)' % (platform, distribution)
+        else:
+            msg_platform = platform
+        self.module.fail_json(
+            msg='hostname module cannot be used on platform %s' % msg_platform)
+
+class Hostname(object):
+    """
+    This is a generic Hostname manipulation class that is subclassed
+    based on platform.
+
+    A subclass may wish to set different strategy instance to self.strategy.
+
+    All subclasses MUST define platform and distribution (which may be None).
+    """
+
+    platform = 'Generic'
+    distribution = None
+    strategy_class = UnimplementedStrategy
+
+    def __new__(cls, *args, **kwargs):
+        return load_platform_subclass(Hostname, args, kwargs)
+
+    def __init__(self, module):
+        self.module   = module
+        self.name     = module.params['name']
+        self.strategy = self.strategy_class(module)
+
+    def get_current_hostname(self):
+        return self.strategy.get_current_hostname()
+
+    def set_current_hostname(self, name):
+        self.strategy.set_current_hostname(name)
+
+    def get_permanent_hostname(self):
+        return self.strategy.get_permanent_hostname()
+
+    def set_permanent_hostname(self, name):
+        self.strategy.set_permanent_hostname(name)
+
+class GenericStrategy(object):
+    """
+    This is a generic Hostname manipulation strategy class.
+
+    A subclass may wish to override some or all of these methods.
+      - get_current_hostname()
+      - get_permanent_hostname()
+      - set_current_hostname(name)
+      - set_permanent_hostname(name)
+    """
+    def __init__(self, module):
+        self.module = module
+
+    HOSTNAME_CMD = '/bin/hostname'
+
+    def get_current_hostname(self):
+        cmd = [self.HOSTNAME_CMD]
+        rc, out, err = self.module.run_command(cmd)
+        if rc != 0:
+            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
+                (rc, out, err))
+        return out.strip()
+
+    def set_current_hostname(self, name):
+        cmd = [self.HOSTNAME_CMD, name]
+        rc, out, err = self.module.run_command(cmd)
+        if rc != 0:
+            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
+                (rc, out, err))
+
+    def get_permanent_hostname(self):
+        return None
+
+    def set_permanent_hostname(self, name):
+        pass
+
+# ===========================================
+
+class DebianStrategy(GenericStrategy):
+    """
+    This is a Debian family Hostname manipulation strategy class - it edits
+    the /etc/hostname file.
+    """
+
+    HOSTNAME_FILE = '/etc/hostname'
+
+    def get_permanent_hostname(self):
+        try:
+            f = open(self.HOSTNAME_FILE)
+            try:
+                return f.read().strip()
+            finally:
+                f.close()
+        except Exception, err:
+            self.module.fail_json(msg="failed to read hostname: %s" %
+                str(err))
+
+    def set_permanent_hostname(self, name):
+        try:
+            f = open(self.HOSTNAME_FILE, 'w+')
+            try:
+                f.write("%s\n" % name)
+            finally:
+                f.close()
+        except Exception, err:
+            self.module.fail_json(msg="failed to update hostname: %s" %
+                str(err))
+
+class DebianHostname(Hostname):
+    platform = 'Linux'
+    distribution = 'Debian'
+    strategy_class = DebianStrategy
+
+class UbuntuHostname(Hostname):
+    platform = 'Linux'
+    distribution = 'Ubuntu'
+    strategy_class = DebianStrategy
+
+# ===========================================
+
+class RedHatStrategy(GenericStrategy):
+    """
+    This is a Redhat Hostname strategy class - it edits the
+    /etc/sysconfig/network file.
+    """
+    NETWORK_FILE = '/etc/sysconfig/network'
+
+    def get_permanent_hostname(self):
+        try:
+            f = open(self.NETWORK_FILE, 'rb')
+            try:
+                for line in f.readlines():
+                    if line.startswith('HOSTNAME'):
+                        k, v = line.split('=')
+                        return v.strip()
+            finally:
+                f.close()
+        except Exception, err:
+            self.module.fail_json(msg="failed to read hostname: %s" %
+                str(err))
+
+    def set_permanent_hostname(self, name):
+        try:
+            lines = []
+            f = open(self.NETWORK_FILE, 'rb')
+            try:
+                for line in f.readlines():
+                    if line.startswith('HOSTNAME'):
+                        lines.append("HOSTNAME=%s\n" % name)
+                    else:
+                        lines.append(line)
+            finally:
+                f.close()
+            f = open(self.NETWORK_FILE, 'w+')
+            try:
+                f.writelines(lines)
+            finally:
+                f.close()
+        except Exception, err:
+            self.module.fail_json(msg="failed to update hostname: %s" %
+                str(err))
+
+class RedHatHostname(Hostname):
+    platform = 'Linux'
+    distribution = 'Red hat enterprise linux server'
+    strategy_class = RedHatStrategy
+
+class CentOSHostname(Hostname):
+    platform = 'Linux'
+    distribution = 'Centos'
+    strategy_class = RedHatStrategy
+
+# ===========================================
+
+class FedoraStrategy(GenericStrategy):
+    """
+    This is a Fedora family Hostname manipulation strategy class - it uses
+    the hostnamectl command.
+    """
+
+    def get_current_hostname(self):
+        cmd = ['hostname']
+        rc, out, err = self.module.run_command(cmd)
+        if rc != 0:
+            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
+                (rc, out, err))
+        return out.strip()
+
+    def set_current_hostname(self, name):
+        cmd = ['hostnamectl', '--transient', 'set-hostname', name]
+        rc, out, err = self.module.run_command(cmd)
+        if rc != 0:
+            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
+                (rc, out, err))
+
+    def get_permanent_hostname(self):
+        cmd = 'hostnamectl status | awk \'/^ *Static hostname:/{printf("%s", $3)}\''
+        rc, out, err = self.module.run_command(cmd)
+        if rc != 0:
+            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
+                (rc, out, err))
+	return out
+
+    def set_permanent_hostname(self, name):
+        cmd = ['hostnamectl', '--pretty', 'set-hostname', name]
+        rc, out, err = self.module.run_command(cmd)
+        if rc != 0:
+            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
+                (rc, out, err))
+        cmd = ['hostnamectl', '--static', 'set-hostname', name]
+        rc, out, err = self.module.run_command(cmd)
+        if rc != 0:
+            self.module.fail_json(msg="Command failed rc=%d, out=%s, err=%s" %
+                (rc, out, err))
+
+class FedoraHostname(Hostname):
+    platform = 'Linux'
+    distribution = 'Fedora'
+    strategy_class = FedoraStrategy
+
+class OpenSUSEHostname(Hostname):
+    platform = 'Linux'
+    distribution = 'Opensuse '
+    strategy_class = FedoraStrategy
+
+class ArchHostname(Hostname):
+    platform = 'Linux'
+    distribution = 'Arch'
+    strategy_class = FedoraStrategy
+
+# ===========================================
+
+def main():
+    module = AnsibleModule(
+        argument_spec = dict(
+            name=dict(required=True, type='str')
+        )
+    )
+
+    hostname = Hostname(module)
+
+    changed = False
+    name = module.params['name']
+    current_name = hostname.get_current_hostname()
+    if current_name != name:
+        hostname.set_current_hostname(name)
+        changed = True
+
+    permanent_name = hostname.get_permanent_hostname()
+    if permanent_name != name:
+        hostname.set_permanent_hostname(name)
+        changed = True
+
+    module.exit_json(changed=changed, name=name)
+
+# include magic from lib/ansible/module_common.py
+#<<INCLUDE_ANSIBLE_MODULE_COMMON>>
+main()