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authorRobert Collins <rbtcollins@hp.com>2014-01-28 19:20:40 +1300
committerRobert Collins <rbtcollins@hp.com>2014-01-29 01:39:27 +1300
commitc071255ad6bf1fb2c9db6799e96b509295f53fc9 (patch)
treecaf081f072674cbb9861308f2e5a617157370f3d /tripleo_heat_merge
parent23c8aac2bacfee96e0faedb84d0b72893f13c6ec (diff)
Make scaling out a feature for merge.py.
This is a simple implementation designed to work with our current non-HOT approach. We need to adjust our templates a little to support this - though future work could make that better, it's orthogonal to this effort. Change-Id: I555617e5f24a5882de915f057dc02e008c81e753
Diffstat (limited to 'tripleo_heat_merge')
-rw-r--r--tripleo_heat_merge/merge.py106
1 files changed, 104 insertions, 2 deletions
diff --git a/tripleo_heat_merge/merge.py b/tripleo_heat_merge/merge.py
index 2975bd02..7b5951a3 100644
--- a/tripleo_heat_merge/merge.py
+++ b/tripleo_heat_merge/merge.py
@@ -4,6 +4,97 @@ import yaml
import argparse
+def apply_scaling(template, scaling, in_copies=None):
+ """Apply a set of scaling operations to template.
+
+ This is a single pass recursive function: for each call we process one
+ dict or list and recurse to handle children containers.
+
+ Values are handled via scale_value.
+
+ Keys in dicts are always copied per the scaling rule.
+ Values are either replaced or copied depending on whether the given
+ scaling rule is in in_copies.
+ """
+ in_copies = dict(in_copies or {})
+ # Shouldn't be needed but to avoid unexpected side effects/bugs we short
+ # circuit no-ops.
+ if not scaling:
+ return template
+ if isinstance(template, dict):
+ new_template = {}
+ for key, value in template.items():
+ for prefix, copy_num, new_key in scale_value(
+ key, scaling, in_copies):
+ if prefix:
+ # e.g. Compute0, 1, Compute1Foo
+ in_copies[prefix] = prefix[:-1] + str(copy_num)
+ if isinstance(value, (dict, list)):
+ new_value = apply_scaling(value, scaling, in_copies)
+ new_template[new_key] = new_value
+ else:
+ new_values = list(scale_value(value, scaling, in_copies))
+ # We have nowhere to multiply a non-container value of a
+ # dict, so it may be copied or unchanged but not scaled.
+ assert len(new_values) == 1
+ new_template[new_key] = new_values[0][2]
+ if prefix:
+ del in_copies[prefix]
+ return new_template
+ elif isinstance(template, list):
+ new_template = []
+ for value in template:
+ if isinstance(value, (dict, list)):
+ new_template.append(apply_scaling(value, scaling, in_copies))
+ else:
+ for _, _, new_value in scale_value(value, scaling, in_copies):
+ new_template.append(new_value)
+ return new_template
+ else:
+ raise Exception("apply_scaling called with non-container %r" % template)
+
+
+def scale_value(value, scaling, in_copies):
+ """Scale out a value.
+
+ :param value: The value to scale (not a container).
+ :param scaling: The scaling map to use.
+ :param in_copies: What containers we're currently copying.
+ :return: An iterator of the new values for the value as tuples:
+ (prefix, copy_num, value). E.g. Compute0, 1, Compute1Foo
+ prefix and copy_num are only set when:
+ - a prefix in scaling matches value
+ - and that prefix is not in in_copies
+ """
+ if isinstance(value, (str, unicode)):
+ for prefix, copies in scaling.items():
+ if not value.startswith(prefix):
+ continue
+ suffix = value[len(prefix):]
+ if prefix in in_copies:
+ # Adjust to the copy number we're on
+ yield None, None, in_copies[prefix] + suffix
+ return
+ else:
+ for n in range(copies):
+ yield prefix, n, prefix[:-1] + str(n) + suffix
+ return
+ yield None, None, value
+ else:
+ yield None, None, value
+
+
+def parse_scaling(scaling_args):
+ """Translate a list of scaling requests to a dict prefix:count."""
+ scaling_args = scaling_args or []
+ result = {}
+ for item in scaling_args:
+ key, value = item.split('=')
+ value = int(value)
+ result[key + '0'] = value
+ return result
+
+
def _translate_role(role, master_role, slave_roles):
if not master_role:
return role
@@ -92,18 +183,27 @@ def main(argv=None):
parser.add_argument('--output',
help='File to write output to. - for stdout',
default='-')
+ parser.add_argument('--scale', action="append",
+ help="Names to scale out. Pass Prefix=1 to cause a key Prefix0Foo to "
+ "be copied to Prefix1Foo in the output, and value Prefix0Bar to be"
+ "renamed to Prefix1Bar inside that copy, or copied to Prefix1Bar "
+ "outside of any copy.")
args = parser.parse_args(argv)
templates = args.templates
+ scaling = parse_scaling(args.scale)
merged_template = merge(templates, args.master_role, args.slave_roles,
- args.included_template_dir)
+ args.included_template_dir, scaling=scaling)
if args.output == '-':
out_file = sys.stdout
else:
out_file = file(args.output, 'wt')
out_file.write(merged_template)
+
def merge(templates, master_role=None, slave_roles=None,
- included_template_dir=INCLUDED_TEMPLATE_DIR):
+ included_template_dir=INCLUDED_TEMPLATE_DIR,
+ scaling=None):
+ scaling = scaling or {}
errors = []
end_template={'HeatTemplateFormatVersion': '2012-12-12',
'Description': []}
@@ -192,6 +292,8 @@ def merge(templates, master_role=None, slave_roles=None,
end_template['Resources'] = {}
end_template['Resources'][r] = rbody
+ end_template = apply_scaling(end_template, scaling)
+
def fix_ref(item, old, new):
if isinstance(item, dict):
copy_item = dict(item)