Test Optimization Proposal (SC-736) (#1188)

Reduce template rendering test runtime

3 files changed, 84 insertions, 33 deletions

diff --git a/cloudinit/templater.py b/cloudinit/templater.py
index c215bbbb..1e147d4a 100644
--- a/cloudinit/templater.py
+++ b/cloudinit/templater.py
@@ -12,6 +12,7 @@
 
 import collections
 import re
+import sys
 
 try:
     from Cheetah.Template import Template as CTemplate
@@ -32,6 +33,7 @@ except (ImportError, AttributeError):
 from cloudinit import log as logging
 from cloudinit import type_utils as tu
 from cloudinit import util
+from cloudinit.atomic_helper import write_file
 
 LOG = logging.getLogger(__name__)
 TYPE_MATCHER = re.compile(r"##\s*template:(.*)", re.I)
@@ -180,4 +182,17 @@ def render_string(content, params):
     return renderer(content, params)
 
 
+def render_cloudcfg(variant, template, output):
+
+    with open(template, "r") as fh:
+        contents = fh.read()
+    tpl_params = {"variant": variant}
+    contents = (render_string(contents, tpl_params)).rstrip() + "\n"
+    util.load_yaml(contents)
+    if output == "-":
+        sys.stdout.write(contents)
+    else:
+        write_file(output, contents, omode="w")
+
+
 # vi: ts=4 expandtab
diff --git a/tests/unittests/test_render_cloudcfg.py b/tests/unittests/test_render_cloudcfg.py
index 81110e61..01a728da 100644
--- a/tests/unittests/test_render_cloudcfg.py
+++ b/tests/unittests/test_render_cloudcfg.py
@@ -4,7 +4,7 @@ import sys
 
 import pytest
 
-from cloudinit import subp, util
+from cloudinit import subp, templater, util
 from tests.unittests.helpers import cloud_init_project_dir
 
 # TODO(Look to align with tools.render-cloudcfg or cloudinit.distos.OSFAMILIES)
@@ -32,10 +32,22 @@ class TestRenderCloudCfg:
     cmd = [sys.executable, cloud_init_project_dir("tools/render-cloudcfg")]
     tmpl_path = cloud_init_project_dir("config/cloud.cfg.tmpl")
 
+    def test_variant_sets_distro_in_cloud_cfg_subp(self, tmpdir):
+        outfile = tmpdir.join("outcfg").strpath
+
+        subp.subp(self.cmd + ["--variant", "ubuntu", self.tmpl_path, outfile])
+        with open(outfile) as stream:
+            system_cfg = util.load_yaml(stream.read())
+        assert system_cfg["system_info"]["distro"] == "ubuntu"
+
     @pytest.mark.parametrize("variant", (DISTRO_VARIANTS))
     def test_variant_sets_distro_in_cloud_cfg(self, variant, tmpdir):
+        """Testing parametrized inputs with imported function saves ~0.5s per
+        call versus calling as subp
+        """
         outfile = tmpdir.join("outcfg").strpath
-        subp.subp(self.cmd + ["--variant", variant, self.tmpl_path, outfile])
+
+        templater.render_cloudcfg(variant, self.tmpl_path, outfile)
         with open(outfile) as stream:
             system_cfg = util.load_yaml(stream.read())
         if variant == "unknown":
@@ -44,8 +56,11 @@ class TestRenderCloudCfg:
 
     @pytest.mark.parametrize("variant", (DISTRO_VARIANTS))
     def test_variant_sets_default_user_in_cloud_cfg(self, variant, tmpdir):
+        """Testing parametrized inputs with imported function saves ~0.5s per
+        call versus calling as subp
+        """
         outfile = tmpdir.join("outcfg").strpath
-        subp.subp(self.cmd + ["--variant", variant, self.tmpl_path, outfile])
+        templater.render_cloudcfg(variant, self.tmpl_path, outfile)
         with open(outfile) as stream:
             system_cfg = util.load_yaml(stream.read())
 
@@ -69,8 +84,11 @@ class TestRenderCloudCfg:
     def test_variant_sets_network_renderer_priority_in_cloud_cfg(
         self, variant, renderers, tmpdir
     ):
+        """Testing parametrized inputs with imported function saves ~0.5s per
+        call versus calling as subp
+        """
         outfile = tmpdir.join("outcfg").strpath
-        subp.subp(self.cmd + ["--variant", variant, self.tmpl_path, outfile])
+        templater.render_cloudcfg(variant, self.tmpl_path, outfile)
         with open(outfile) as stream:
             system_cfg = util.load_yaml(stream.read())
 
diff --git a/tools/render-cloudcfg b/tools/render-cloudcfg
index 6642bd58..c14097b5 100755
--- a/tools/render-cloudcfg
+++ b/tools/render-cloudcfg
@@ -1,47 +1,65 @@
 #!/usr/bin/env python3
 
-import argparse
 import os
 import sys
-
-VARIANTS = ["almalinux", "alpine", "amazon", "arch", "centos", "cloudlinux", "debian",
-            "eurolinux", "fedora", "freebsd", "miraclelinux", "netbsd", "openbsd", "openEuler", "photon",
-            "rhel", "suse","rocky", "ubuntu", "unknown", "virtuozzo"]
+import argparse
 
 
-if "avoid-pep8-E402-import-not-top-of-file":
+def main():
     _tdir = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
     sys.path.insert(0, _tdir)
-    from cloudinit import templater
-    from cloudinit import util
-    from cloudinit.atomic_helper import write_file
-
+    from cloudinit import templater, util  # pylint: disable=E0401
 
-def main():
+    VARIANTS = [
+        "almalinux",
+        "alpine",
+        "amazon",
+        "arch",
+        "centos",
+        "cloudlinux",
+        "debian",
+        "eurolinux",
+        "fedora",
+        "freebsd",
+        "miraclelinux",
+        "netbsd",
+        "openbsd",
+        "openEuler",
+        "photon",
+        "rhel",
+        "suse",
+        "rocky",
+        "ubuntu",
+        "unknown",
+        "virtuozzo",
+    ]
     parser = argparse.ArgumentParser()
     platform = util.system_info()
     parser.add_argument(
-        "--variant", default=platform['variant'], action="store",
-        help="define the variant.", choices=VARIANTS)
+        "--variant",
+        default=platform["variant"],
+        action="store",
+        help="define the variant.",
+        choices=VARIANTS,
+    )
     parser.add_argument(
-        "template", nargs="?", action="store",
-        default='./config/cloud.cfg.tmpl',
-        help="Path to the cloud.cfg template")
+        "template",
+        nargs="?",
+        action="store",
+        default="./config/cloud.cfg.tmpl",
+        help="Path to the cloud.cfg template",
+    )
     parser.add_argument(
-        "output", nargs="?", action="store", default="-",
-        help="Output file.  Use '-' to write to stdout")
+        "output",
+        nargs="?",
+        action="store",
+        default="-",
+        help="Output file.  Use '-' to write to stdout",
+    )
 
-    args = parser.parse_args()
+    args = parser.parse_args(sys.argv[1:])
+    templater.render_cloudcfg(args.variant, args.template, args.output)
 
-    with open(args.template, 'r') as fh:
-        contents = fh.read()
-    tpl_params = {'variant': args.variant}
-    contents = (templater.render_string(contents, tpl_params)).rstrip() + "\n"
-    util.load_yaml(contents)
-    if args.output == "-":
-        sys.stdout.write(contents)
-    else:
-        write_file(args.output, contents, omode="w")
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()