Add utilities to get ansible variables by hostname or group name

tests/common/utilities.py

@@ -7,6 +7,13 @@
 import sys
 import threading
 import time
+import re
+
+from ansible.parsing.dataloader import DataLoader
+from ansible.inventory.manager import InventoryManager
+from ansible.vars.manager import VariableManager
+
+logger = logging.getLogger(__name__)
 
 
 def wait(seconds, msg=""):
@@ -15,7 +22,7 @@ def wait(seconds, msg=""):
     @param seconds: Number of seconds to pause
     @param msg: Optional extra message for pause reason
     """
-    logging.info("Pause %d seconds, reason: %s" % (seconds, msg))
+    logger.info("Pause %d seconds, reason: %s" % (seconds, msg))
     time.sleep(seconds)
 
 
@@ -30,29 +37,29 @@ def wait_until(timeout, interval, condition, *args, **kwargs):
     @return: If the condition function returns True before timeout, return True. If the condition function raises an
         exception, log the error and keep waiting and polling.
     """
-    logging.debug("Wait until %s is True, timeout is %s seconds, checking interval is %s" % \
+    logger.debug("Wait until %s is True, timeout is %s seconds, checking interval is %s" % \
         (condition.__name__, timeout, interval))
     start_time = time.time()
     elapsed_time = 0
     while elapsed_time < timeout:
-        logging.debug("Time elapsed: %f seconds" % elapsed_time)
+        logger.debug("Time elapsed: %f seconds" % elapsed_time)
 
         try:
             check_result = condition(*args, **kwargs)
         except Exception as e:
-            logging.error("Exception caught while checking %s: %s" % (condition.__name__, repr(e)))
+            logger.error("Exception caught while checking %s: %s" % (condition.__name__, repr(e)))
             check_result = False
 
         if check_result:
-            logging.debug("%s is True, exit early with True" % condition.__name__)
+            logger.debug("%s is True, exit early with True" % condition.__name__)
             return True
         else:
-            logging.debug("%s is False, wait %d seconds and check again" % (condition.__name__, interval))
+            logger.debug("%s is False, wait %d seconds and check again" % (condition.__name__, interval))
             time.sleep(interval)
             elapsed_time = time.time() - start_time
 
     if elapsed_time >= timeout:
-        logging.debug("%s is still False after %d seconds, exit with False" % (condition.__name__, timeout))
+        logger.debug("%s is still False after %d seconds, exit with False" % (condition.__name__, timeout))
         return False
 
 
@@ -70,7 +77,7 @@ def wait_tcp_connection(client, server_hostname, listening_port, timeout_s = 30)
                           timeout=timeout_s,
                           module_ignore_errors=True)
     if 'exception' in res:
-        logging.warn("Failed to establish TCP connection to %s:%d, timeout=%d" % (str(server_hostname), listening_port, timeout_s))
+        logger.warn("Failed to establish TCP connection to %s:%d, timeout=%d" % (str(server_hostname), listening_port, timeout_s))
         return False
     return True
 
@@ -127,3 +134,134 @@ def join_all(threads, timeout):
     else:
         raise RuntimeError("Timeout on waiting threads: %s" %
                            [repr(thread) for thread in threads])
+
+
+def get_inventory_manager(inv_files):
+    return InventoryManager(loader=DataLoader(), sources=inv_files)
+
+
+def get_variable_manager(inv_files):
+    return VariableManager(loader=DataLoader(), inventory=get_inventory_manager(inv_files))
+
+
+def get_host_vars(inv_files, hostname, variable=None):
+    """Use ansible's InventoryManager to get value of variables defined for the specified host in the specified
+    inventory files.
+
+    Args:
+        inv_files (list or string): List of inventory file pathes, or string of a single inventory file path. In tests,
+            it can be get from request.config.getoption("ansible_inventory").
+        hostname (string): Hostname
+        variable (string or None): Variable name. Defaults to None.
+
+    Returns:
+        string or dict or None: If variable name is specified, return the variable value. If variable is not found,
+            return None. If variable name is not specified, return all variables in a dictionary. If the host is not
+            found, return None.
+    """
+    im = get_inventory_manager(inv_files)
+    host = im.get_host(hostname)
+    if not host:
+        logger.error("Unable to find host {} in {}".format(hostname, str(inv_files)))
+        return None
+
+    if variable:
+        return host.vars.get(variable, None)
+    else:
+        return host.vars
+
+
+def get_host_visible_vars(inv_files, hostname, variable=None):
+    """Use ansible's VariableManager and InventoryManager to get value of variables visible to the specified host.
+    The variable could be defined in host_vars or in group_vars that the host belongs to.
+
+    Args:
+        inv_files (list or string): List of inventory file pathes, or string of a single inventory file path. In tests,
+            it can be get from request.config.getoption("ansible_inventory").
+        hostname (string): Hostname
+        variable (string or None): Variable name. Defaults to None.
+
+    Returns:
+        string or dict or None: If variable name is specified, return the variable value. If variable is not found,
+            return None. If variable name is not specified, return all variables in a dictionary. If the host is not
+            found, return None.
+    """
+    vm = get_variable_manager(inv_files)
+    im = vm._inventory
+    host = im.get_host(hostname)
+    if not host:
+        logger.error("Unable to find host {} in {}".format(hostname, str(inv_files)))
+        return None
+    if variable:
+        return vm.get_vars(host=host).get(variable, None)
+    else:
+        return vm.get_vars(host=host)
+
+
+def get_group_visible_vars(inv_files, group_name, variable=None):
+    """Use ansible's VariableManager and InventoryManager to get value of variables visible to the first host belongs
+    to the specified group. The variable could be defined in host_vars of the first host or in group_vars that the host
+    belongs to.
+
+    Args:
+        inv_files (list or string): List of inventory file pathes, or string of a single inventory file path. In tests,
+            it can be get from request.config.getoption("ansible_inventory").
+        group_name (string): Name of group in ansible inventory.
+        variable (string or None): Variable name. Defaults to None.
+
+    Returns:
+        string or dict or None: If variable name is specified, return the variable value. If variable is not found,
+            return None. If variable name is not specified, return all variables in a dictionary. If the group is not
+            found or there is no host in the group, return None.
+    """
+    vm = get_variable_manager(inv_files)
+    im = vm._inventory
+    group = im.groups.get(group_name, None)
+    if not group:
+        logger.error("Unable to find group {} in {}".format(group_name, str(inv_files)))
+        return None
+    group_hosts = group.get_hosts()
+    if len(group_hosts) == 0:
+        logger.error("No host in group {}".format(group_name))
+        return None
+    first_host = group_hosts[0]
+    if variable:
+        return vm.get_vars(host=first_host).get(variable, None)
+    else:
+        return vm.get_vars(host=first_host)
+
+
+def get_test_server_vars(inv_files, server, variable=None):
+    """Use ansible's VariableManager and InventoryManager to get value of variables of test server belong to specified
+    server group.
+
+    In testbed.csv file, we can get the server name of each test setup under the 'server' column. For example
+    'server_1', 'server_2', etc. This server name is indeed a group name in used ansible inventory files. This group
+    contains children groups for test server and VMs. This function is try to just return the variables of test servers
+    belong to the specified server group.
+
+    Args:
+        inv_files (list or string): List of inventory file pathes, or string of a single inventory file path. In tests,
+            it can be get from request.config.getoption("ansible_inventory").
+        server (string): Server of test setup in testbed.csv file.
+        variable (string or None): Variable name. Defaults to None.
+
+    Returns:
+        string or dict or None: If variable name is specified, return the variable value. If variable is not found,
+            return None. If variable name is not specified, return all variables in a dictionary. If the server group
+            is not found or there is no test server host in the group, return None.
+    """
+    vm = get_variable_manager(inv_files)
+    im = vm._inventory
+    group = im.groups.get(server, None)
+    if not group:
+        logger.error("Unable to find group {} in {}".format(server, str(inv_files)))
+        return None
+    for host in group.get_hosts():
+        if not re.match(r'VM\d+', host.name):   # This must be the test server host
+            if variable:
+                return host.vars.get(variable, None)
+            else:
+                return host.vars
+    logger.error("Unable to find test server host under group {}".format(server))
+    return None