schema cli: Add schema subcommand to cloud-init cli and cc_runcmd schema

This branch does a few things:
  - Add 'schema' subcommand to cloud-init CLI for validating
    cloud-config files against strict module jsonschema definitions
  - Add --annotate parameter to 'cloud-init schema' to annotate
    existing cloud-config file content with validation errors
  - Add jsonschema definition to cc_runcmd
  - Add unit test coverage for cc_runcmd
  - Update CLI capabilities documentation

This branch only imports development (and analyze) subparsers when the
specific subcommand is provided on the CLI to avoid adding costly unused
file imports during cloud-init system boot.

The schema command allows a person to quickly validate a cloud-config text
file against cloud-init's known module schemas to avoid costly roundtrips
deploying instances in their cloud of choice. As of this branch, only
cc_ntp and cc_runcmd cloud-config modules define schemas. Schema
validation will ignore all undefined config keys until all modules define
a strict schema.

To perform validation of runcmd and ntp sections of a cloud-config file:
$ cat > cloud.cfg <<EOF
runcmd: bogus
EOF
$ python -m cloudinit.cmd.main schema --config-file cloud.cfg

$ python -m cloudinit.cmd.main schema --config-file cloud.cfg \
  --annotate

Once jsonschema is defined for all ~55 cc modules, we will move this
schema subcommand up as a proper subcommand of the cloud-init CLI.

3 files changed, 40 insertions, 7 deletions

diff --git a/cloudinit/cmd/devel/__init__.py b/cloudinit/cmd/devel/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/cloudinit/cmd/devel/__init__.py
diff --git a/cloudinit/cmd/devel/parser.py b/cloudinit/cmd/devel/parser.py
new file mode 100644
index 00000000..acacc4ed
--- /dev/null
+++ b/cloudinit/cmd/devel/parser.py
@@ -0,0 +1,26 @@
+# Copyright (C) 2017 Canonical Ltd.
+#
+# This file is part of cloud-init. See LICENSE file for license information.
+
+"""Define 'devel' subcommand argument parsers to include in cloud-init cmd."""
+
+import argparse
+from cloudinit.config.schema import (
+    get_parser as schema_parser, handle_schema_args)
+
+
+def get_parser(parser=None):
+    if not parser:
+        parser = argparse.ArgumentParser(
+            prog='cloudinit-devel',
+            description='Run development cloud-init tools')
+    subparsers = parser.add_subparsers(title='Subcommands', dest='subcommand')
+    subparsers.required = True
+
+    parser_schema = subparsers.add_parser(
+        'schema', help='Validate cloud-config files or document schema')
+    # Construct schema subcommand parser
+    schema_parser(parser_schema)
+    parser_schema.set_defaults(action=('schema', handle_schema_args))
+
+    return parser
diff --git a/cloudinit/cmd/main.py b/cloudinit/cmd/main.py
index 9c0ac864..5b467979 100644
--- a/cloudinit/cmd/main.py
+++ b/cloudinit/cmd/main.py
@@ -705,7 +705,6 @@ def main(sysv_args=None):
     subparsers.required = True
 
     # Each action and its sub-options (if any)
-
     parser_init = subparsers.add_parser('init',
                                         help=('initializes cloud-init and'
                                               ' performs initial modules'))
@@ -762,12 +761,20 @@ def main(sysv_args=None):
 
     parser_analyze = subparsers.add_parser(
         'analyze', help='Devel tool: Analyze cloud-init logs and data')
-    if sysv_args and sysv_args[0] == 'analyze':
-        # Only load this parser if analyze is specified to avoid file load cost
-        # FIXME put this under 'devel' subcommand (coming in next branch)
-        from cloudinit.analyze.__main__ import get_parser as analyze_parser
-        # Construct analyze subcommand parser
-        analyze_parser(parser_analyze)
+
+    parser_devel = subparsers.add_parser(
+        'devel', help='Run development tools')
+
+    if sysv_args:
+        # Only load subparsers if subcommand is specified to avoid load cost
+        if sysv_args[0] == 'analyze':
+            from cloudinit.analyze.__main__ import get_parser as analyze_parser
+            # Construct analyze subcommand parser
+            analyze_parser(parser_analyze)
+        if sysv_args[0] == 'devel':
+            from cloudinit.cmd.devel.parser import get_parser as devel_parser
+            # Construct devel subcommand parser
+            devel_parser(parser_devel)
 
     args = parser.parse_args(args=sysv_args)