Refactor inventory code out of Runner.

This introduces the Inventory class.

Playbook uses the internals of Runner to limit the number of hosts to poll
asynchronously. To accomodate this, Inventory can be restricted to specific
hosts.

lib/ansible/inventory.py

@@ -0,0 +1,189 @@
+# (c) 2012, Michael DeHaan <michael.dehaan@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/>.
+
+#############################################
+
+import fnmatch
+import os
+import subprocess
+
+import constants as C
+from ansible import errors
+from ansible import utils
+
+class Inventory(object):
+    """ Host inventory for ansible.
+
+    The inventory is either a simple text file with systems and [groups] of 
+    systems, or a script that will be called with --list or --host.
+    """
+
+    def __init__(self, host_list=C.DEFAULT_HOST_LIST, extra_vars=None):
+
+        self._restriction = None
+
+        if type(host_list) == list:
+            self.host_list = host_list
+            self.groups = dict(ungrouped=host_list)
+            self._is_script = False
+            return
+
+        inventory_file = os.path.expanduser(host_list)
+        if not os.path.exists(inventory_file):
+            raise errors.AnsibleFileNotFound("inventory file not found: %s" % host_list)
+
+        self.inventory_file = os.path.abspath(inventory_file)
+
+        if os.access(self.inventory_file, os.X_OK):
+            self.host_list, self.groups = self._parse_from_script(extra_vars)
+            self._is_script = True
+        else:
+            self.host_list, self.groups = self._parse_from_file()
+            self._is_script = False
+
+    # *****************************************************
+    # Public API
+
+    def list_hosts(self, pattern="all"):
+        """ Return a list of hosts [matching the pattern] """
+        if self._restriction is None:
+            host_list = self.host_list
+        else:
+            host_list = [ h for h in self.host_list if h in self._restriction ]
+        return [ h for h in host_list if self._matches(h, pattern) ]
+
+    def restrict_to(self, restriction):
+        """ Restrict list operations to the hosts given in restriction """
+        if type(restriction)!=list:
+            restriction = [ restriction ]
+
+        self._restriction = restriction
+
+    def lift_restriction(self):
+        """ Do not restrict list operations """
+        self._restriction = None
+
+    def get_variables(self, host, extra_vars=None):
+        """ Return the variables associated with this host. """
+
+        if not self._is_script:
+            return {}
+
+        return self._get_variables_from_script(host, extra_vars)
+
+    # *****************************************************
+
+    def _parse_from_file(self):
+        ''' parse a textual host file '''
+
+        results = []
+        groups = dict(ungrouped=[])
+        lines = file(self.inventory_file).read().split("\n")
+        group_name = 'ungrouped'
+        for item in lines:
+            item = item.lstrip().rstrip()
+            if item.startswith("#"):
+                # ignore commented out lines
+                pass
+            elif item.startswith("["):
+                # looks like a group
+                group_name = item.replace("[","").replace("]","").lstrip().rstrip()
+                groups[group_name] = []
+            elif item != "":
+                # looks like a regular host
+                groups[group_name].append(item)
+                if not item in results:
+                    results.append(item)
+        return (results, groups)
+
+    # *****************************************************
+
+    def _parse_from_script(self, extra_vars=None):
+        ''' evaluate a script that returns list of hosts by groups '''
+
+        results = []
+        groups = dict(ungrouped=[])
+
+        cmd = [self.inventory_file, '--list']
+
+        if extra_vars:
+            cmd.extend(['--extra-vars', extra_vars])
+
+        cmd = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=False)
+        out, err = cmd.communicate()
+        rc = cmd.returncode
+        if rc:
+            raise errors.AnsibleError("%s: %s" % self.inventory_file, err)
+
+        try:
+            groups = utils.json_loads(out)
+        except:
+            raise errors.AnsibleError("invalid JSON response from script: %s" % self.inventory_file)
+
+        for (groupname, hostlist) in groups.iteritems():
+            for host in hostlist:
+                if host not in results:
+                    results.append(host)
+        return (results, groups)
+
+    # *****************************************************
+
+    def _get_variables_from_script(self, host, extra_vars=None):
+        ''' support per system variabes from external variable scripts, see web docs '''
+
+        cmd = [self.inventory_file, '--host', host]
+
+        if extra_vars:
+            cmd.extend(['--extra-vars', extra_vars])
+
+        cmd = subprocess.Popen(cmd,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            shell=False
+        )
+        out, err = cmd.communicate()
+
+        variables = {}
+        try:
+            variables = utils.json_loads(out)
+        except:
+            raise errors.AnsibleError("%s returned invalid result when called with hostname %s" % (
+                self.inventory_file,
+                host
+            ))
+        return variables
+
+    def _matches(self, host_name, pattern):
+        ''' returns if a hostname is matched by the pattern '''
+
+        # a pattern is in fnmatch format but more than one pattern
+        # can be strung together with semicolons. ex:
+        #   atlanta-web*.example.com;dc-web*.example.com
+
+        if host_name == '':
+            return False
+        pattern = pattern.replace(";",":")
+        subpatterns = pattern.split(":")
+        for subpattern in subpatterns:
+            if subpattern == 'all':
+                return True
+            if fnmatch.fnmatch(host_name, subpattern):
+                return True
+            elif subpattern in self.groups:
+                if host_name in self.groups[subpattern]:
+                    return True
+        return False