cli: add cloud-init query subcommand to query instance metadata

Cloud-init caches any cloud metadata crawled during boot in the file
/run/cloud-init/instance-data.json. Cloud-init also standardizes some of
that metadata across all clouds. The command 'cloud-init query' surfaces a
simple CLI to query or format any cached instance metadata so that scripts
or end-users do not have to write tools to crawl metadata themselves.

Since 'cloud-init query' is runnable by non-root users, redact any
sensitive data from instance-data.json and provide a root-readable
unredacted instance-data-sensitive.json. Datasources can now define a
sensitive_metadata_keys tuple which will redact any matching keys
which could contain passwords or credentials from instance-data.json.

Also add the following standardized 'v1' instance-data.json keys:
  - user_data: The base64encoded user-data provided at instance launch
  - vendor_data: Any vendor_data provided to the instance at launch
  - underscore_delimited versions of existing hyphenated keys:
    instance_id, local_hostname, availability_zone, cloud_name

1 files changed, 1 insertions, 6 deletions

diff --git a/cloudinit/cmd/devel/render.py b/cloudinit/cmd/devel/render.py
index e85933db..2ba6b681 100755
--- a/cloudinit/cmd/devel/render.py
+++ b/cloudinit/cmd/devel/render.py
@@ -9,7 +9,6 @@ import sys
 from cloudinit.handlers.jinja_template import render_jinja_payload_from_file
 from cloudinit import log
 from cloudinit.sources import INSTANCE_JSON_FILE
-from cloudinit import util
 from . import addLogHandlerCLI, read_cfg_paths
 
 NAME = 'render'
@@ -54,11 +53,7 @@ def handle_args(name, args):
             paths.run_dir, INSTANCE_JSON_FILE)
     else:
         instance_data_fn = args.instance_data
-    try:
-        with open(instance_data_fn) as stream:
-            instance_data = stream.read()
-        instance_data = util.load_json(instance_data)
-    except IOError:
+    if not os.path.exists(instance_data_fn):
         LOG.error('Missing instance-data.json file: %s', instance_data_fn)
         return 1
     try: