feat: GoCD agent config from templates ISRE-2015

scripts/gocd_configure_elastic_agents.py

@@ -0,0 +1,104 @@
+#! /usr/bin/env python3
+
+"""
+Command-line script used to update the tag of the legacy gocd agent that is currently being used
+"""
+
+import difflib
+import logging
+import os
+import re
+import requests
+import sys
+import traceback
+
+import click
+import jinja2
+
+sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from tubular.gocd_api import (  # pylint: disable=wrong-import-position
+    get_elastic_profile,
+    put_elastic_profile,
+)
+
+logging.basicConfig(stream=sys.stdout, level=logging.INFO)
+LOG = logging.getLogger(__name__)
+
+def is_pod_configuration(ep_property):
+    """
+    Returns true if the key is a pod configuration in
+    a GoCD elastic profile ep_property list
+    """
+    return ep_property['key'] == 'PodConfiguration'
+
+
+def print_diff(a, b, a_title, b_title):
+    """
+    Prints a unified diff similar to linux command diff -u
+    """
+
+    lines_a = a.splitlines(keepends=True)
+    lines_b = b.splitlines(keepends=True)
+
+
+    print(''.join(difflib.unified_diff(lines_a, lines_b, fromfile=a_title, tofile=b_title)))
+
+
+
+def update_image_in_elastic_profile(host, token, profile_id, new_pod_config, apply=False):
+    """
+    Upload the new_pod_config to the specified profile_id
+    """
+
+    assert isinstance(apply, bool)
+
+    response = get_elastic_profile(host, token, profile_id)
+    etag = response.headers['etag']
+    elastic_profile = response.json()
+    pod_configuration_index = next(i for i, v in enumerate(elastic_profile['properties']) if is_pod_configuration(v))
+    pod_configuration = elastic_profile['properties'][pod_configuration_index]
+    pod_configuration_value = pod_configuration['value']
+
+    logging.info("Diff of old and new pod configuration")
+    print_diff(pod_configuration_value, new_pod_config, 'existing_pod_configuration', 'new_pod_configuration')
+
+    if apply:
+      # Now modify the original list since it is copy by value
+      logging.info(f"Applying new agent profile {profile_id}")
+      elastic_profile['properties'][pod_configuration_index]['value'] = new_pod_config
+      put_elastic_profile(host, token, profile_id, etag, elastic_profile)
+    else:
+      logging.info(f"Not applying new agent profile {profile_id} due to missing --apply flag")
+
+
+@click.command()
+@click.option('--host', help='gocd hostname without protocol eg gocd.tools.edx.org', required=True)
+@click.option('--token', help='gocd auth token', required=True)
+@click.option('--agent-image', help='image to change the tag on eg: myregistry/myapp', required=True)
+@click.option('--agent-tag', help='new tag of the image to replace', required=True)
+@click.option('--profile-id', help='new tag of the image to replace', required=True)
+@click.option('--templates-dir', help='Directory holding Jinja2 template files for pod configuration', required=True)
+@click.option('--apply', is_flag=True, default=False,
+              help='Must be present to actually apply chagnes, otherwise we will only print a diff and exit', required=True)
+def update_gocd_legacy_agents(token, host, agent_image, agent_tag, profile_id, templates_dir, apply):
+    """
+    For the specified profile get the pod yaml and replace the tag of any images that
+    match with the new tag for a given profile
+    """
+    j2_environment = jinja2.Environment(
+      loader=jinja2.FileSystemLoader(templates_dir)
+    )
+    j2_template = j2_environment.get_template(f"{profile_id}.yaml.j2")
+    #print(j2_template.render(image=image, tag=tag))
+    new_pod_config = j2_template.render(agent_image=agent_image, agent_tag=agent_tag)
+    try:
+        logging.info(f"Updating agent profile {profile_id} with agent image {agent_image}:{agent_tag}")
+        update_image_in_elastic_profile(host, token, profile_id, new_pod_config, apply)
+    except Exception as err:  # pylint: disable=broad-except
+        traceback.print_exc()
+        click.secho('{}'.format(err), fg='red')
+        sys.exit(1)
+
+if __name__ == "__main__":
+    update_gocd_legacy_agents()  # pylint: disable=no-value-for-parameter