infra-nimbus/ansible/terraform.py

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#! /usr/bin/env python2
import json
import os
import re
import subprocess
import sys
def _tf_env():
# way to figure out currenly used TF workspace
try:
with open(TERRAFORM_ENV) as f:
return f.read()
except:
return 'default'
TERRAFORM_PATH = os.environ.get('ANSIBLE_TF_BIN', 'terraform')
TERRAFORM_DIR = os.environ.get('ANSIBLE_TF_DIR', os.getcwd())
TERRAFORM_BPK = os.path.join(TERRAFORM_DIR, '.terraform/terraform.tfstate.backup')
TERRAFORM_ENV = os.path.join(TERRAFORM_DIR, '.terraform/environment')
ANSIBLE_BKP = os.path.join(TERRAFORM_DIR, 'ansible/inventory', _tf_env())
def _extract_dict(attrs, key):
out = {}
for k in attrs.keys():
match = re.match(r"^" + key + r"\.(.*)", k)
if not match or match.group(1) == "%":
continue
out[match.group(1)] = attrs[k]
return out
def _extract_list(attrs, key):
out = []
length_key = key + ".#"
if length_key not in attrs.keys():
return []
length = int(attrs[length_key])
if length < 1:
return []
for i in range(0, length):
out.append(attrs["{}.{}".format(key, i)])
return out
def _init_group(children=None, hosts=None, vars=None):
return {
"hosts": [] if hosts is None else hosts,
"vars": {} if vars is None else vars,
"children": [] if children is None else children
}
def _add_host(inventory, hostname, groups, host_vars):
inventory["_meta"]["hostvars"][hostname] = host_vars
for group in groups:
if group not in inventory.keys():
inventory[group] = _init_group(hosts=[hostname])
elif hostname not in inventory[group]:
inventory[group]["hosts"].append(hostname)
def _add_group(inventory, group_name, children, group_vars):
if group_name not in inventory.keys():
inventory[group_name] = _init_group(children=children, vars=group_vars)
else:
# Start out with support for only one "group" with a given name
# If there's a second group by the name, last in wins
inventory[group_name]["children"] = children
inventory[group_name]["vars"] = group_vars
def _init_inventory():
return {
"all": _init_group(),
"_meta": {
"hostvars": {}
}
}
def _handle_host(attrs, inventory):
host_vars = _extract_dict(attrs, "vars")
groups = _extract_list(attrs, "groups")
hostname = attrs["inventory_hostname"]
if "all" not in groups:
groups.append("all")
_add_host(inventory, hostname, groups, host_vars)
def _handle_group(attrs, inventory):
group_vars = _extract_dict(attrs, "vars")
children = _extract_list(attrs, "children")
group_name = attrs["inventory_group_name"]
_add_group(inventory, group_name, children, group_vars)
def _walk_state(tfstate, inventory):
for module in tfstate["modules"]:
for resource in module["resources"].values():
if not resource["type"].startswith("ansible_"):
continue
attrs = resource["primary"]["attributes"]
if resource["type"] == "ansible_host":
_handle_host(attrs, inventory)
if resource["type"] == "ansible_group":
_handle_group(attrs, inventory)
return inventory
def _backup_tf(tfstate):
# Crates a state backup in case we lose Consul
with open(TERRAFORM_BPK, 'w') as f:
f.write(json.dumps(tfstate))
def _backup_ansible(inventory):
# Crates a state backup in Ansible inventory format
text = '# NOTE: This file is generated by terraform.py\n'
text += '# For emergency use when Consul fails\n'
text += '[all]\n'
for host in inventory['_meta']['hostvars'].values():
text += (
'{hostname} hostname={hostname} ansible_host={ansible_host} '+
'env={env} stage={stage} data_center={data_center} region={region} '+
'dns_entry={dns_entry}\n'
).format(**host)
text += '\n'
for name, hosts in inventory.iteritems():
if name in ['_meta', 'all']:
continue
text += '[{}]\n'.format(name)
for host in hosts['hosts']:
text += '{}\n'.format(host)
text += '\n'
with open(ANSIBLE_BKP, 'w') as f:
f.write(text)
def _main():
try:
tf_command = [TERRAFORM_PATH, 'state', 'pull', '-input=false']
proc = subprocess.Popen(tf_command, cwd=TERRAFORM_DIR, stdout=subprocess.PIPE)
tfstate = json.load(proc.stdout)
# format state for ansible
inventory = _walk_state(tfstate, _init_inventory())
# print out for ansible
sys.stdout.write(json.dumps(inventory, indent=2))
# backup raw TF state
_backup_tf(tfstate)
# backup ansible inventory
_backup_ansible(inventory)
except Exception as ex:
print(ex)
sys.exit(1)
if __name__ == '__main__':
_main()