From 52a8840d31eaf25ecc3d00e9921c9bda71640e5f Mon Sep 17 00:00:00 2001
From: Tomas Tomecek <ttomecek@redhat.com>
Date: Feb 13 2018 18:50:36 +0000
Subject: [PATCH 1/2] inventory,qcow2: remove noop


Signed-off-by: Tomas Tomecek <ttomecek@redhat.com>

---

diff --git a/inventory/standard-inventory-qcow2 b/inventory/standard-inventory-qcow2
index 7a6feea..0a571ac 100755
--- a/inventory/standard-inventory-qcow2
+++ b/inventory/standard-inventory-qcow2
@@ -119,7 +119,6 @@ def host(image):
         os.dup2(tty, 2)
     except OSError:
         tty = None
-        pass
 
     # A directory for temporary stuff
     directory = tempfile.mkdtemp(prefix="inventory-cloud")

From 8e0be63ff5ed7edef0d436365f03376117c96ea9 Mon Sep 17 00:00:00 2001
From: Tomas Tomecek <ttomecek@redhat.com>
Date: Feb 15 2018 08:30:27 +0000
Subject: [PATCH 2/2] inventory,qcow2: add a way to lock on a file


I am using the inventory script directly from a playbook. The thing is
that Ansible creates a long chain of processes and if the VM's parent
process waits on its parent process, the VM is terminated sometime
during a playbook run.

This commit adds a way to lock on a presence of a file, not just a
process.

Signed-off-by: Tomas Tomecek <ttomecek@redhat.com>

---

diff --git a/README.md b/README.md
index 364df0e..f27d712 100644
--- a/README.md
+++ b/README.md
@@ -10,3 +10,52 @@ a QCow2 image into a virtual machine, or installing an RPM.
 
 Tests are not required to use these scripts but they provide useful, usable
 defaults for this task.
+
+
+## `standard-inventory-qcow2`
+
+This inventory script launches a virtual machine via qemu. The VM image should
+be specified via command line or an environment variable `TEST_SUBJECTS`.
+
+By default, the virtual machine is killed when the process (your shell) it
+invoked the script, is gone. This behavior may not be desirable when invoking
+the inventory script from an Ansible playbook (since Ansible spawns a long
+hierarchy of processes). For that purpose you can use environment variable `LOCK_ON_FILE`: the VM will be killed once the file specified by this variable is missing. Let's look at an example:
+
+```yaml
+---
+- hosts: localhost
+  vars:
+    # path to the VM image to use
+    vm_image: "./Fedora-Cloud-Base-27-1.6.x86_64.qcow2"
+    # inventory name of the VM
+    vm_name: "awesome-vm"
+    # which python interpreter should be used by ansible (e.g. Fedora doesn't have /usr/bin/python)
+    vm_python_interpreter: "/usr/bin/python3"
+    # path to the script which will provision the VM
+    vm_provisioning_script: /usr/share/ansible/inventory/standard-inventory-qcow2
+  tasks:
+  - name: create lock file to synchronize on the VM
+    tempfile:
+      prefix: inventory-cloud
+      suffix: .lock
+      state: file
+    register: tmp_lock_file
+  - name: provision the VM
+    command: "{{ vm_provisioning_script }} {{ vm_image }}"
+    register: vm_provision_data
+    environment:
+      LOCK_ON_FILE: "{{ tmp_lock_file.path }}"
+  - name: prepare inventory data for add_host
+    set_fact:
+      inventory_data: '{{ (vm_provision_data.stdout | from_json)._meta.hostvars[vm_image] }}'
+  - add_host:
+      name: "{{ vm_name }}"
+      ansible_ssh_common_args: "{{ inventory_data.ansible_ssh_common_args }}"
+      ansible_ssh_host: "{{ inventory_data.ansible_ssh_host }}"
+      ansible_ssh_pass: "{{ inventory_data.ansible_ssh_pass }}"
+      ansible_ssh_port: "{{ inventory_data.ansible_ssh_port }}"
+      ansible_ssh_private_key_file: "{{ inventory_data.ansible_ssh_private_key_file }}"
+      ansible_ssh_user: "{{ inventory_data.ansible_ssh_user }}"
+      ansible_python_interpreter: "{% if vm_python_interpreter != '' %}{{ vm_python_interpreter }}{% else %}/usr/bin/python2{% endif %}"
+```
diff --git a/inventory/standard-inventory-qcow2 b/inventory/standard-inventory-qcow2
index 0a571ac..ab8c8bc 100755
--- a/inventory/standard-inventory-qcow2
+++ b/inventory/standard-inventory-qcow2
@@ -234,15 +234,23 @@ def host(image):
     os.dup2(tty, 1)
     os.dup2(tty, 2)
 
-    # Now wait for the parent process to go away, then kill the VM
+    # alternatively, lock on a file
+    lock_file = os.environ.get("LOCK_ON_FILE", None)
     while True:
         time.sleep(3)
 
-        try:
-            os.kill(ppid, 0)
-            os.kill(proc.pid, 0)
-        except OSError:
-            break # Either of the processes no longer exist
+        if lock_file:
+            if not os.path.exists(lock_file):
+                sys.stderr.write("Lock file is gone.")
+                break
+        else:
+            # Now wait for the parent process to go away, then kill the VM
+            try:
+                os.kill(ppid, 0)
+                os.kill(proc.pid, 0)
+            except OSError:
+                sys.stderr.write("Either parent process or VM process is gone.")
+                break # Either of the processes no longer exist
 
     if diagnose:
         sys.stderr.write("\n")