Fix fallback logic

doozer/doozerlib/metadata.py

@@ -1,5 +1,6 @@
 import datetime
 import io
+import os
 import pathlib
 import re
 import fnmatch
@@ -17,7 +18,7 @@
 
 import artcommonlib
 import doozerlib
-from artcommonlib import logutil, exectools
+from artcommonlib import logutil, exectools, assertion
 from artcommonlib.assembly import assembly_basis_event, assembly_metadata_config
 from artcommonlib.pushd import Dir
 from artcommonlib.model import Missing, Model
@@ -285,6 +286,22 @@ def hotfix_brew_tags(self):
         """
         return [self.hotfix_brew_tag()]
 
+    def source_path(self):
+        """
+        :return: Returns the directory containing the source which should be used to populate distgit. This includes
+                the source.path subdirectory if the metadata includes one.
+        """
+
+        source_root = self.runtime.resolve_source(self)
+        sub_path = self.config.content.source.path
+
+        path = source_root
+        if sub_path is not Missing:
+            path = os.path.join(source_root, sub_path)
+
+        assertion.isdir(path, "Unable to find path for source [%s] for config: %s" % (path, self.config_filename))
+        return path
+
     def get_arches(self):
         """
         :return: Returns the list of architecture this image/rpm should build for. This is an intersection
@@ -676,17 +693,27 @@ def get_component_name(self) -> str:
     def resolve_dockerfile_name(self) -> str:
         """
         :return: Upstream Dockerfile name
-        If content.source.dockerfile is not specified, use content.source.dockerfile_fallback
-        If content.source.dockerfile_fallback is not specified, use "Dockerfile"
+        Resolve the Dockerfile name of upstream. If file specified in content.source.dockerfile doesn't exist,
+        try looking at the one specified in content.source.dockerfile_fallback as well.
         """
-        dockerfile_name = "Dockerfile"
         if self.config.content.source.dockerfile is not Missing:
-            # Be aware that this attribute sometimes contains path elements
+            # Be aware that this attribute sometimes contains path elements too.
             dockerfile_name = self.config.content.source.dockerfile
-        elif self.config.content.source.dockerfile_fallback is not Missing:
-            dockerfile_name = self.config.content.source.dockerfile_fallback
-            self.logger.info(f"source.dockerfile not found, using source.dockerfile_fallback {dockerfile_name}")
-        return dockerfile_name
+
+            source_dockerfile_path = os.path.join(self.source_path(), dockerfile_name)
+
+            if not os.path.isfile(source_dockerfile_path):
+                dockerfile_name_fallback = self.config.content.source.dockerfile_fallback
+                if dockerfile_name_fallback is not Missing:
+                    self.logger.info(
+                        f"Could not find source dockerfile at {dockerfile_name}, using fallback {dockerfile_name_fallback}")
+                    return dockerfile_name_fallback
+                raise IOError(
+                    f"Fallback dockerfile {dockerfile_name_fallback} is Missing and source dockerfile {source_dockerfile_path} doesn't exist")
+            else:
+                return dockerfile_name
+        else:
+            return "Dockerfile"
 
     def needs_rebuild(self):
         if self.config.targets: