问题
Is there a way to use the Ansible Python API to get a list of hosts from a given inventory file / group combination?
For example, our inventory files are split up by service type:
[dev:children]
dev_a
dev_b
[dev_a]
my.host.int.abc.com
[dev_b]
my.host.int.xyz.com
[prod:children]
prod_a
prod_b
[prod_a]
my.host.abc.com
[prod_b]
my.host.xyz.com
Can I use ansible.inventory in some way to pass in a specific inventory file, and the group I want to act on, and have it return a list of hosts that match?
回答1:
I was struggling with this as well for awhile, but found a solution through trial & error.
One of the key advantages to the API is that you can pull variables and metadata, not just hostnames.
Starting from Python API - Ansible Documentation:
#!/usr/bin/env python
# Ansible: initialize needed objects
variable_manager = VariableManager()
loader = DataLoader()
# Ansible: Load inventory
inventory = Inventory(
loader = loader,
variable_manager = variable_manager,
host_list = 'hosts', # Substitute your filename here
)
This gives you an Inventory instance, which has methods and properties to provide groups and hosts.
To expand further (and provide examples of Group and Host classes), here's a snippet I wrote which serializes the inventory as a list of groups, with each group having a 'hosts' attribute that is a list of each host's attributes.
#/usr/bin/env python
def serialize(inventory):
if not isinstance(inventory, Inventory):
return dict()
data = list()
for group in inventory.get_groups():
if group != 'all':
group_data = inventory.get_group(group).serialize()
# Seed host data for group
host_data = list()
for host in inventory.get_group(group).hosts:
host_data.append(host.serialize())
group_data['hosts'] = host_data
data.append(group_data)
return data
# Continuing from above
serialized_inventory = serialize(inventory)
I ran this against my lab of four F5 BIG-IP's, and this is the result (trimmed):
<!-- language: lang-json -->
[{'depth': 1,
'hosts': [{'address': u'bigip-ve-03',
'name': u'bigip-ve-03',
'uuid': UUID('b5e2180b-964f-41d9-9f5a-08a0d7dd133c'),
'vars': {u'hostname': u'bigip-ve-03.local',
u'ip': u'10.128.1.130'}}],
'name': 'ungrouped',
'vars': {}},
{'depth': 1,
'hosts': [{'address': u'bigip-ve-01',
'name': u'bigip-ve-01',
'uuid': UUID('3d7daa57-9d98-4fa6-afe1-5f1e03db4107'),
'vars': {u'hostname': u'bigip-ve-01.local',
u'ip': u'10.128.1.128'}},
{'address': u'bigip-ve-02',
'name': u'bigip-ve-02',
'uuid': UUID('72f35cd8-6f9b-4c11-b4e0-5dc5ece30007'),
'vars': {u'hostname': u'bigip-ve-02.local',
u'ip': u'10.128.1.129'}},
{'address': u'bigip-ve-04',
'name': u'bigip-ve-04',
'uuid': UUID('255526d0-087e-44ae-85b1-4ce9192e03c1'),
'vars': {}}],
'name': u'bigip',
'vars': {u'password': u'admin', u'username': u'admin'}}]
回答2:
Do the same trick from before, but instead of all, pass the group name you want to list:
ansible (group name here) -i (inventory file here) --list-hosts
回答3:
For me following worked
from ansible.parsing.dataloader import DataLoader
from ansible.inventory.manager import InventoryManager
if __name__ == '__main__':
inventory_file_name = 'my.inventory'
data_loader = DataLoader()
inventory = InventoryManager(loader = data_loader,
sources=[inventory_file_name])
print(inventory.get_groups_dict()['spark-workers'])
inventory.get_groups_dict() returns a dictionary that you can use to get hosts by using the group_name as key as shown in the code.
You will have to install ansible package you can do by pip as follows
pip install ansible
回答4:
I had a similar problem and I think nitzmahone's approach of not using unsupported calls to the Python API. Here's a working solution, relying on the nicely JSON-formatted output of ansible-inventory CLI:
pip install ansible==2.4.0.0 sh==1.12.14
An example inventory file, inventory/qa.ini:
[lxlviewer-server]
id-qa.kb.se
[xl_auth-server]
login.libris.kb.se
[export-server]
export-qa.libris.kb.se
[import-server]
import-vcopy-qa.libris.kb.se
[rest-api-server]
api-qa.libris.kb.se
[postgres-server]
pgsql01-qa.libris.kb.se
[elasticsearch-servers]
es01-qa.libris.kb.se
es02-qa.libris.kb.se
es03-qa.libris.kb.se
[tomcat-servers:children]
export-server
import-server
rest-api-server
[flask-servers:children]
lxlviewer-server
xl_auth-server
[apache-servers:children]
lxlviewer-server
[nginx-servers:children]
xl_auth-server
A Python 2.7 function to extract info (easily extendable to hostvars et cetera):
import json
from sh import Command
def _get_hosts_from(inventory_path, group_name):
"""Return list of hosts from `group_name` in Ansible `inventory_path`."""
ansible_inventory = Command('ansible-inventory')
json_inventory = json.loads(
ansible_inventory('-i', inventory_path, '--list').stdout)
if group_name not in json_inventory:
raise AssertionError('Group %r not found.' % group_name)
hosts = []
if 'hosts' in json_inventory[group_name]:
return json_inventory[group_name]['hosts']
else:
children = json_inventory[group_name]['children']
for child in children:
if 'hosts' in json_inventory[child]:
for host in json_inventory[child]['hosts']:
if host not in hosts:
hosts.append(host)
else:
grandchildren = json_inventory[child]['children']
for grandchild in grandchildren:
if 'hosts' not in json_inventory[grandchild]:
raise AssertionError('Group nesting cap exceeded.')
for host in json_inventory[grandchild]['hosts']:
if host not in hosts:
hosts.append(host)
return hosts
Proof that it works (also with child and grandchild groups):
In [1]: from fabfile.conf import _get_hosts_from
In [2]: _get_hosts_from('inventory/qa.ini', 'elasticsearch-servers')
Out[2]: [u'es01-qa.libris.kb.se', u'es02-qa.libris.kb.se', u'es03-qa.libris.kb.se']
In [3]: _get_hosts_from('inventory/qa.ini', 'flask-servers')
Out[3]: [u'id-qa.kb.se', u'login.libris.kb.se']
In [4]:
回答5:
There has been changes to Ansible API since the approved answer:
This works for Ansible 2.8 (and maybe more)
Here's the way I was able to access most of the data:
from ansible.parsing.dataloader import DataLoader
from ansible.inventory.manager import InventoryManager
loader = DataLoader()
# Sources can be a single path or comma separated paths
inventory = InventoryManager(loader=loader, sources='path/to/file')
# My use case was to have all:vars as the 1st level keys, and have groups as key: list pairs.
# I also don't have anything ungrouped, so there might be a slightly better solution to this.
# Your use case may be different, so you can customize this to how you need it.
x = {}
ignore = ('all', 'ungrouped')
x.update(inventory.groups['all'].serialize()['vars'])
group_dict = inventory.get_groups_dict()
for group in inventory.groups:
if group in ignore:
continue
x.update({
group: group_dict[group]
})
Example:
Input:
[all:vars]
x=hello
y=world
[group_1]
youtube
google
[group_2]
stack
overflow
Output:
{"x":"hello","y":"world","group_1":["youtube","google"],"group_2":["stack","overflow"]}
Again, your use case might be different than mine, so you'll have to slightly change the code to how you want it to be.
来源：https://stackoverflow.com/questions/37623849/how-can-i-get-a-list-of-hosts-from-an-ansible-inventory-file