Add additional debugging

packetnetworking/builder.py

@@ -66,6 +66,9 @@ def run(self, rootfs_path):
         builder.build()
         return builder.run(rootfs_path)
 
+    def as_dict(self):
+        return {"metadata": self.metadata, "network": self.network.as_dict()}
+
 
 class NetworkData(object):
     def __init__(self, default_resolvers=None, default_private_subnets=None):
@@ -117,3 +120,13 @@ def build_addresses(self):
 
     def build_resolvers(self):
         self.resolvers = utils.resolvers(self.resolvers)
+
+    def as_dict(self):
+        return {
+            "bonding": self.bonding,
+            "interfaces": self.interfaces,
+            "bonds": self.bonds,
+            "addresses": self.addresses,
+            "resolvers": self.resolvers,
+            "private_subnets": self.private_subnets,
+        }

packetnetworking/cli.py

@@ -36,7 +36,12 @@
         + "(otherwise uses ones from /etc/resolv.conf)"
     ),
 )
-@click.option("-n", "--max-attempts", default=10, help="retry up to N times on failure")
+@click.option(
+    "-n",
+    "--max-attempts",
+    default=10,
+    help="Retry up to N times on failure when downloading metadata from a url",
+)
 @click.option("-v", "--verbose", count=True, help="Provide more detailed output")
 @click.option("-q", "--quiet", is_flag=True, help="Silences all output")
 def cli(
@@ -91,6 +96,10 @@ def cli(
             )
             break
         except Exception as exc:
+            # If a metadata file has been passed, retrying won't result in a
+            # different outcome.
+            if metadata_file:
+                raise
             if attempt == max_attempts:
                 raise
             attempt += 1

packetnetworking/distros/distro_builder.py

@@ -1,9 +1,11 @@
 import os
 import sys
 import logging
+import json
 from textwrap import dedent
 
 from jinja2 import Template, StrictUndefined
+from jinja2.exceptions import UndefinedError
 
 from ..utils import Tasks, package_dir
 
@@ -107,6 +109,7 @@ def all_tasks(self):
                     tasks.update(builder.tasks)
         return tasks
 
+    # pylama:ignore=C901
     def render(self):
         """
         Render compiles each task template into the final content.
@@ -139,21 +142,35 @@ def render(self):
                 if fmt:
                     template = template.format(**fmt)
 
-            template = Template(
-                dedent(template),
+            template = dedent(template)
+            tmpl = Template(
+                template,
                 keep_trailing_newline=True,
                 lstrip_blocks=True,
                 trim_blocks=True,
                 undefined=StrictUndefined,
             )
-            if file_mode or mode:
-                rendered_tasks[path] = {
-                    "file_mode": file_mode,
-                    "mode": mode,
-                    "content": template.render(self.context()),
-                }
-            else:
-                rendered_tasks[path] = template.render(self.context())
+            try:
+                if file_mode or mode:
+                    rendered_tasks[path] = {
+                        "file_mode": file_mode,
+                        "mode": mode,
+                        "content": tmpl.render(self.context()),
+                    }
+                else:
+                    rendered_tasks[path] = tmpl.render(self.context())
+            except UndefinedError:
+                # having to use print as log.* isn't printing out the json
+                print(
+                    "==== METADATA ====\n"
+                    + json.dumps(self.metadata.as_dict(), indent=2),
+                    file=sys.stderr,
+                )
+                log.error(
+                    "An exception occured while processing task "
+                    + "'{}' with template:\n{}".format(path, template)
+                )
+                raise
         return rendered_tasks
 
     def run(self, rootfs_path):