Read become password from pass

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

ansible.cfg

@@ -1,13 +1,15 @@
 [defaults]
 # Explicitely redefined some defaults to make play execution work
 roles_path = ./roles
+vars_plugins = ./vars_plugins
 
 inventory = ./hosts
 timeout = 60
 
 [privilege_escalation]
 become = True
-become_ask_pass = True
+# Use a separate module to read passwords from pass
+become_ask_pass = False
 
 [ssh_connection]
 pipelining = True

vars_plugins/pass.ini

@@ -0,0 +1,6 @@
+[pass]
+# password_store_dir=/home/ynerant/.password-store
+# crans_password_store_submodule=crans
+
+[pass_become]
+all=templier

vars_plugins/pass.ini.example

@@ -0,0 +1,6 @@
+[pass]
+# password_store_dir=/home/me/.password-store
+# crans_password_store_submodule=crans
+
+[pass_become]
+# all=mdp-root

vars_plugins/pass.py

@@ -0,0 +1,102 @@
+#!/usr/bin/env python
+
+from functools import lru_cache
+from getpass import getpass
+import os
+from pathlib import Path
+import subprocess
+import sys
+
+from ansible.module_utils.six.moves import configparser
+from ansible.plugins.vars import BaseVarsPlugin
+
+
+DOCUMENTATION = """
+    module: pass
+    vars: vault
+    version_added: 2.9
+    short_description: Load vault passwords from pass
+    description:
+        - Works exactly as a vault, loading variables from pass.
+        - Decrypts the YAML file `ansible_vault` from cranspasswords.
+        - Loads the secret variables.
+        - Makes use of data caching in order to avoid calling cranspasswords multiple times.
+        - Uses the local gpg key from the user running ansible on the Control node.
+"""
+
+
+
+class VarsModule(BaseVarsPlugin):
+    @staticmethod
+    @lru_cache
+    def decrypt_password(name, crans_submodule=False):
+        """
+        Passwords are decrypted from the local password store, then are cached.
+        By that way, we don't decrypt these passwords everytime.
+        """
+        # Load config
+        config = configparser.ConfigParser()
+        config.read(os.path.join(os.path.dirname(os.path.realpath(__file__)), 'pass.ini'))
+
+        password_store = Path(config.get('pass', 'password_store_dir',
+            fallback=os.getenv('PASSWORD_STORE_DIR', Path.home() / '.password-store')))
+
+        if crans_submodule:
+            password_store /= config.get('pass', 'crans_password_store_submodule',
+                    fallback=os.getenv('CRANS_PASSWORD_STORE_SUBMODULE', 'crans'))
+        full_command = ['gpg', '-d', password_store / f'{name}.gpg']
+        proc = subprocess.run(full_command, capture_output=True, close_fds=True)
+        clear_text = proc.stdout.decode('UTF-8')
+        sys.stderr.write(proc.stderr.decode('UTF-8'))
+        return clear_text
+
+    @staticmethod
+    @lru_cache
+    def become_password(entity):
+        """
+        Query the become password that should be used for the given entity.
+        If entity is the whole group that has no default password,
+        the become password will be prompted.
+        The configuration should be given in pass.ini, in the `pass_become`
+        group. You have only to write `group=pass-filename`.
+        """
+        # Load config
+        config = configparser.ConfigParser()
+        config.read(os.path.join(os.path.dirname(os.path.realpath(__file__)), 'pass.ini'))
+        if config.has_option('pass_become', entity.get_name()):
+            return VarsModule.decrypt_password(
+                    config.get('pass_become', entity.get_name())).split('\n')[0]
+        if entity.get_name() == "all":
+            return getpass("BECOME password: ", stream=None)
+        return None
+
+    def get_vars(self, loader, path, entities):
+        """
+        Get all vars for entities, called by Ansible.
+
+        loader: Ansible's DataLoader.
+        path: Current play's playbook directory.
+        entities: Host or group names pertinent to the variables needed.
+        """
+        # VarsModule objects are called every time you need host vars, per host,
+        # and per group the host is part of.
+        # It is about 6 times per host per task in current state
+        # of Ansible Crans configuration.
+
+        # It is way to much.
+        # So we cache the data into the DataLoader (see parsing/DataLoader).
+
+        passwords = {}
+
+        for entity in entities:
+            # Load vault passwords
+            if entity.get_name() == 'all':
+                passwords['vault'] = loader.load(
+                        VarsModule.decrypt_password('ansible_vault', True))
+
+            # Load become password
+            become_password = VarsModule.become_password(entity)
+            if become_password is not None:
+                passwords['ansible_become_password'] = become_password
+
+        return passwords