Add a script to migrate releases from helm2 to helm3

This commit introduces a custom script that will help
migrating helm releases/installs from helm2 to helm3.

The procedure is:

# install the /helm-2to3 plugin

$ mkdir plugin
$ wget https://github.com/helm/helm-2to3/releases/download/v0.9.0/helm-2to3_0.9.0_linux_amd64.tar.gz
$ pushd plugin/
$ tar -xvzf ../helm-2to3_0.9.0_linux_amd64.tar.gz
$ mkdir bin
$ cp 2to3 bin
$ popd
$ export HELM_LINTER_PLUGIN_NO_INSTALL_HOOK=true
$ helm plugin install ./plugin

# move the helm2 config to helm3

$ helm 2to3 move config

# chose a helmv2 release to migrate:

$ helmv2-cli -- helm list -a

# migrate a helm2 release e.g deployment manager

$ ./migrate_helm_release.py deployment-manager

# check if it migrated successfully:

$ helm list -A -a

# it should not be present anymore in helm2:

helmv2-cli -- helm list -a

Change-Id: I9a3370ddc10a307ba87d72837f8e284fbe2594bd
Signed-off-by: Mihnea Saracin <Mihnea.Saracin@windriver.com>
Closes-Bug: 1943834

controllerconfig/centos/controllerconfig.spec

@@ -61,6 +61,7 @@ install -d -m 755 %{buildroot}%{local_bindir}
 install -p -D -m 700 scripts/openstack_update_admin_password %{buildroot}%{local_bindir}/openstack_update_admin_password
 install -p -D -m 700 scripts/upgrade_swact_migration.py %{buildroot}%{local_bindir}/upgrade_swact_migration.py
 install -p -D -m 755 scripts/image-backup.sh %{buildroot}%{local_bindir}/image-backup.sh
+install -p -D -m 755 scripts/migrate_helm_release.py %{buildroot}%{local_bindir}/migrate_helm_release.py
 
 install -d -m 755 %{buildroot}%{local_goenabledd}
 install -p -D -m 700 scripts/config_goenabled_check.sh %{buildroot}%{local_goenabledd}/config_goenabled_check.sh

controllerconfig/controllerconfig/scripts/migrate_helm_release.py

@@ -0,0 +1,118 @@
+#!/usr/bin/env python
+
+
+import keyring
+import psycopg2
+import subprocess
+import sys
+import os
+
+from psycopg2.extras import RealDictCursor
+
+
+def main():
+    if len(sys.argv) != 2:
+        raise Exception("Release name should be specified")
+    release = sys.argv[1]
+    print("Starting to migrate release {}".format(release))
+    conn = init_connection()
+    migrate_release(conn, release)
+
+
+def init_connection():
+    helmv2_db_pw = keyring.get_password("helmv2", "database")
+    if not helmv2_db_pw:
+        raise Exception("Unable to get password to access helmv2 database.")
+
+    return psycopg2.connect(user="admin-helmv2",
+                            password=helmv2_db_pw,
+                            host="localhost",
+                            database="helmv2")
+
+
+def migrate_release(conn, release):
+    release_info = get_release_info(conn, release)
+    release_name = release_info["name"]
+    create_configmap(release_info)
+    helm2to3_migrate(release_name)
+    cleanup_release(conn, release_name)
+
+
+def get_release_info(conn, release):
+    release_info = None
+    with conn:
+        with conn.cursor(cursor_factory=RealDictCursor) as cur:
+            cur.execute("select * from releases where name = %s", (release,))
+            release_info = cur.fetchone()
+            if not release_info:
+                raise Exception("Release name is not present in the DB")
+    return release_info
+
+
+def create_configmap(release_info):
+    configmap_label_name = release_info["name"]
+    configmap = """
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {key}
+  namespace: kube-system
+  labels:
+    NAME: {name}
+    STATUS: {status}
+    OWNER: {owner}
+    VERSION: "{version}"
+data:
+  release: {release}
+""".format(key=release_info["key"],
+           name=configmap_label_name,
+           status=release_info["status"],
+           owner=release_info["owner"],
+           version=release_info["version"],
+           release=release_info["body"])
+
+    configmap_path = os.path.join("/tmp", configmap_label_name + ".yaml")
+    with open(configmap_path, "w") as f:
+        f.write(configmap)
+
+    cmd = "kubectl --kubeconfig=/etc/kubernetes/admin.conf apply -f {}" \
+        .format(configmap_path)
+    execute_command(cmd)
+    print("Configmap {} created".format(configmap_label_name))
+    os.remove(configmap_path)
+
+
+def helm2to3_migrate(release_name):
+    cmd = "helm 2to3 convert --kubeconfig=/etc/kubernetes/admin.conf \
+          --tiller-out-cluster -s configmaps {}" \
+        .format(release_name)
+    execute_command(cmd)
+    print("Migrated {} to helm3".format(release_name))
+
+
+def cleanup_release(conn, release_name):
+    cmd = "helm 2to3 cleanup --kubeconfig=/etc/kubernetes/admin.conf --release-cleanup \
+          --tiller-out-cluster -s configmaps --skip-confirmation --name {}" \
+        .format(release_name)
+    execute_command(cmd)
+    with conn:
+        with conn.cursor() as cur:
+            cur.execute("delete from releases where name = %s",
+                        (release_name,))
+
+    print("Cleaned up helm2 data for {}".format(release_name))
+
+
+def execute_command(cmd):
+    sub = subprocess.Popen(cmd, shell=True,
+                           stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+    stdout, stderr = sub.communicate()
+    if sub.returncode != 0:
+        print("Command failed:\n %s\n%s\n%s" % (cmd, stdout, stderr))
+        raise Exception("Failed to execute command: %s" % cmd)
+    return stdout
+
+
+if __name__ == "__main__":
+    main()