From ea6eb530593e5bfecfacfce1981ecf7ed1ad5bbd Mon Sep 17 00:00:00 2001
From: David Ames <david.ames@canonical.com>
Date: Wed, 8 Aug 2018 16:26:00 -0700
Subject: [PATCH] Series Upgrade

Implement the series-upgrade feature allowing to move between Ubuntu
series.

Change-Id: Idcc77b66e65633eb26e485e93ef7928b7f455ca8
---
 hooks/hooks.py            | 31 +++++++++++++++++++++++++++++++
 hooks/post-series-upgrade |  1 +
 hooks/pre-series-upgrade  |  1 +
 hooks/update-status       |  1 +
 hooks/utils.py            | 11 ++++++++++-
 5 files changed, 44 insertions(+), 1 deletion(-)
 create mode 120000 hooks/post-series-upgrade
 create mode 120000 hooks/pre-series-upgrade
 create mode 120000 hooks/update-status

diff --git a/hooks/hooks.py b/hooks/hooks.py
index e9abe69..54aef91 100755
--- a/hooks/hooks.py
+++ b/hooks/hooks.py
@@ -48,6 +48,13 @@ from charmhelpers.contrib.network.ip import (
     get_relation_ip,
 )
 
+from charmhelpers.contrib.openstack.utils import (
+    is_unit_paused_set,
+    set_unit_upgrading,
+    clear_unit_upgrading,
+    clear_unit_paused,
+)
+
 from charmhelpers.fetch import (
     apt_install,
     apt_purge,
@@ -83,6 +90,8 @@ from utils import (
     needs_maas_dns_migration,
     write_maas_dns_address,
     MAASConfigIncomplete,
+    pause_unit,
+    resume_unit,
 )
 
 from charmhelpers.contrib.charmsupport import nrpe
@@ -133,6 +142,12 @@ def get_transport():
 @hooks.hook('config-changed')
 def config_changed():
 
+    # if we are paused, delay doing any config changed hooks.
+    # It is forced on the resume.
+    if is_unit_paused_set():
+        log("Unit is pause or upgrading. Skipping config_changed", "WARN")
+        return
+
     setup_ocf_files()
 
     if config('prefer-ipv6'):
@@ -481,6 +496,22 @@ def update_nrpe_config():
     nrpe_setup.write()
 
 
+@hooks.hook('pre-series-upgrade')
+def series_upgrade_prepare():
+    set_unit_upgrading()
+    if not is_unit_paused_set():
+        pause_unit()
+
+
+@hooks.hook('post-series-upgrade')
+def series_upgrade_complete():
+    log("Running complete series upgrade hook", "INFO")
+    clear_unit_paused()
+    clear_unit_upgrading()
+    config_changed()
+    resume_unit()
+
+
 if __name__ == '__main__':
     try:
         hooks.execute(sys.argv)
diff --git a/hooks/post-series-upgrade b/hooks/post-series-upgrade
new file mode 120000
index 0000000..9416ca6
--- /dev/null
+++ b/hooks/post-series-upgrade
@@ -0,0 +1 @@
+hooks.py
\ No newline at end of file
diff --git a/hooks/pre-series-upgrade b/hooks/pre-series-upgrade
new file mode 120000
index 0000000..9416ca6
--- /dev/null
+++ b/hooks/pre-series-upgrade
@@ -0,0 +1 @@
+hooks.py
\ No newline at end of file
diff --git a/hooks/update-status b/hooks/update-status
new file mode 120000
index 0000000..9416ca6
--- /dev/null
+++ b/hooks/update-status
@@ -0,0 +1 @@
+hooks.py
\ No newline at end of file
diff --git a/hooks/utils.py b/hooks/utils.py
index cb9822b..c4d4cc7 100644
--- a/hooks/utils.py
+++ b/hooks/utils.py
@@ -47,6 +47,7 @@ from charmhelpers.contrib.openstack.utils import (
     set_unit_paused,
     clear_unit_paused,
     is_unit_paused_set,
+    is_unit_upgrading_set,
 )
 from charmhelpers.contrib.openstack.ha.utils import (
     assert_charm_supports_dns_ha
@@ -849,7 +850,7 @@ def pause_unit():
     status, message = assess_status_helper()
     if status != 'active':
         messages.append(message)
-    if messages:
+    if messages and not is_unit_upgrading_set():
         raise Exception("Couldn't pause: {}".format("; ".join(messages)))
     else:
         set_unit_paused()
@@ -863,6 +864,14 @@ def assess_status_helper():
     @returns status, message - status is workload status and message is any
                                corresponding messages
     """
+
+    if is_unit_upgrading_set():
+        return ("blocked",
+                "Ready for do-release-upgrde. Set complete when finished")
+    if is_unit_paused_set():
+        return ("maintenance",
+                "Paused. Use 'resume' action to resume normal service.")
+
     node_count = int(config('cluster_count'))
     status = 'active'
     message = 'Unit is ready and clustered'