A Simple Ansible Inventory Generator

=Overview=

This simple library makes it easier to write the glue code between infrastructure bringup/orchestration and software provisioning stages of a one-click deployment.

Head over to the wiki page for more explanation about this project.

=Installation=

pip install ansinv

=Working with inventory hosts=

Creating a host with optional host variables:

host1 = ansinv.AnsibleHost("192.168.10.11", affinity=12, scan="no")

Get a host's ip/name using AnsibleHost.name attribute:

print(host1.name)

Read/Update a host's host variables using AnsibleHost.hostvars attribute:

print(host1.hostvars["scan"])
host1.hostvars["affinity"] = 5
host1.hostvars.update(x=100)

=Working with inventory groups=

Creating a group with optional group variables:

group1 = ansinv.AnsibleGroup("group1", ssh_port=8800)

Get a group's name using AnsibleGroup.name attribute:

print(group1.name)

Read/Update a group's group variables using the AnsibleGroup.groupvars attribute:

print(group1.groupvars["ssh_port"])
group1.groupvars["ssh_port"] = 22
group1.groupvars.update(x=100)

Adding hosts to a group using AnsibleGroup.add_hosts method:

group1.add_hosts(host1, host2, ...) # host1, host2, etc. must already exist
group1.add_hosts(ansinv.AnsibleHost("192.168.12.12", hostvar1="value")) # creating and adding hosts at the same time

Please note: Adding a host actually creates a copy of the host object under the group. So to make modifications to a host object after it has been added, use AnsibleGroup.host method as described below.

Get access to a member host using AnsibleGroup.host('hostname') method:

group1.host("192.168.1.12").hostvars["hostvar1"] = "new value"

Please note: The host() method will always return the first occurrence of the given 'hostname', even if there are multiple hosts with same name in the group. This behavior assumes that even though you are allowed to have multiple hosts with same name but you will never actually require such a case.

Get a list of all host objects in a group using AnsibleGroup.hosts attribute:

print(group1.hosts[0].name)

Establish parent-child relation between groups using AnsibleGroup.add_children method:

child1 = AnsibleGroup("master")
child2 = AnsibleGroup("worker")
parent = AnsibleGroup("cluster")
parent.add_children(child1, child2)
parent.add_children(parent)   # ValueError when trying to add itself as a child
child1.add_children(parent)   # ValueError when trying to add a parent group as a child

Check whether the group is a parent of given group using AnsibleGroup.is_parent_of method:

group1.is_parent_of(group2)   # Returns a bool value

Check whether the group is a child of given group using AnsibleGroup.is_child_of method:

group1.is_child_of(group2)   # Returns a bool value

Get a list of all child objects using AnsibleGroup.children attribute:

print(group1.children[0].name)

=Working with the inventory itself=

Creating an inventory:

inv = AnsibleInventory()   # empty inventory
inv = AnsibleInventory(AnsibleHost("h1"), AnsibleHost("h2"))   # inventory initialized with two ungrouped hosts

Add (ungrouped) hosts to the inventory using AnsibleInventory.add_hosts method:

h1 = AnsibleHost("h1")
h2 = AnsibleHost("h2")
inv.add_hosts(h1, h2)

Please note: The hosts added directly to the inventory are 'ungrouped' hosts i.e. they will not appear under other groups.

Add groups to the inventory using AnsibleInventory.add_groups method:

g1 = AnsibleGroup("g1")
g2 = AnsibleGroup("g2")
inv.add_groups(g1, g2)

Please note: Adding a host/group actually creates a copy of the host/group object under the inventory. So to make modifications to a host/group object after it has been added, use AnsibleInventory.host(hostname)/AnsibleInventory.group(groupname) methods as described below.

Get an ungrouped host object from the inventory using AnsibleInventory.host method:

print(inv.host("h1"))
inv.host("h1").hostvars["somevar"] = 111  # modify an ungrouped host after it has been added to the inventory

Get a group object from the inventory using AnsibleInventory.group('groupname') method:

inv.group("g1").groupvars["x"] = 1111
inv.group("g1").host("h1").hostvars["somevar"] = 333

Please note: The group() method will always return the first occurrence of the given 'groupname', even if there are multiple groups with same name in the inventory. This behavior assumes that even though you are allowed to have multiple groups with same name but you will never actually require such a case.

Get a list of all group objects from the inventory using AnsibleInventory.groups attribute:

for grp in inv.groups:
   print(grp.name)

Get the whole inventory as a string object:

The string version of the inventory is in the INI format which you can simply write to a file and pass the file to Ansible.

inv = AnsibleInventory()
...   # add some groups and hosts
print(str(inv))
with open("inventory", "w") as f:
   f.write(str(inv))

For more explanation and a full example please visit the wiki page.