From 18598b671bc67542e14bab8aadfcb9f806fd0e14 Mon Sep 17 00:00:00 2001
From: Felipe Monteiro <felipe.monteiro@att.com>
Date: Sat, 6 Oct 2018 22:16:12 -0400
Subject: [PATCH] fix: Stop adding unwanted newlines in multiline strings

This patch set fixes a `pegleg site render` issue in which pyyaml
is adding unwanted (multiple) newlines in multiline strings in the
output. In other words, currently, `pegleg site render` keeps injecting
additional newline characters in multiline certificates, such that
each newline is rendered, in effect, as two newlines.

For example:

  -----BEGIN CERTIFICATE-----
  MIIDSDCCAjCgAwIBAgIUegkh/antB1XyDVHdP5dv+0MZyBcwDQYJKoZIhvcNAQEL
  BQAwKjETMBEGA1UEChMKS3ViZXJuZXRlczETMBEGA1UEAxMKa3ViZXJuZXRlczAe
  <snip>

Currently renders as:

  -----BEGIN CERTIFICATE-----

  MIIDSDCCAjCgAwIBAgIUegkh/antB1XyDVHdP5dv+0MZyBcwDQYJKoZIhvcNAQEL

  BQAwKjETMBEGA1UEChMKS3ViZXJuZXRlczETMBEGA1UEAxMKa3ViZXJuZXRlczAe
  <snip>

This patch set adds code to pegleg.engine.__init__ to use the
solution prescribed in [0] to force pyyaml to ensure that the
rendered output for such multiline strings matches the original
input.

Note that this requires using safe_dump(_all) which should be
used in Pegleg ubiquitously for the same reason as [1]. Using
safe_dump(_all) for all CLI actions will be done in a follow up
change.

[0] https://stackoverflow.com/questions/45004464/yaml-dump-adding-unwanted-newlines-in-multiline-strings
[1] https://review.openstack.org/#/c/578240/

Change-Id: I3d53b310869e5eacf3d7a17b51ff9ae462d64736
---
 pegleg/engine/__init__.py | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/pegleg/engine/__init__.py b/pegleg/engine/__init__.py
index 1be97f21..f4c42b72 100644
--- a/pegleg/engine/__init__.py
+++ b/pegleg/engine/__init__.py
@@ -12,8 +12,30 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import yaml
+
 # flake8: noqa
-from . import lint
-from . import repository
-from . import site
-from . import type
+from pegleg.engine import lint
+from pegleg.engine import repository
+from pegleg.engine import site
+from pegleg.engine import type
+
+
+def __represent_multiline_yaml_str():
+    """Compel ``yaml`` library to use block style literals for multi-line
+    strings to prevent unwanted multiple newlines.
+
+    """
+
+    yaml.SafeDumper.org_represent_str = yaml.SafeDumper.represent_str
+
+    def repr_str(dumper, data):
+        if '\n' in data:
+            return dumper.represent_scalar(
+                'tag:yaml.org,2002:str', data, style='|')
+        return dumper.org_represent_str(data)
+
+    yaml.add_representer(str, repr_str, Dumper=yaml.SafeDumper)
+
+
+__represent_multiline_yaml_str()