Add a "build-single" command to build a blob without its dependencies.

...while at the same time making sure that all dependencies are marked
for staging prior to building the blob itself.

1 files changed, 35 insertions, 2 deletions

diff --git a/morphlib/builder.py b/morphlib/builder.py
index 038ec564..53127223 100644
--- a/morphlib/builder.py
+++ b/morphlib/builder.py
@@ -546,8 +546,8 @@ class Builder(object):
                 
                 for parent in blob.parents:
                     for item, filename in built_items:
-                        self.msg('Marking %s to be staged for %s'
-                                 % (item, parent))
+                        self.msg('Marking %s to be staged for %s' %
+                                 (item, parent))
 
                     parent_builder = builders[parent]
                     parent_builder.stage_items += built_items
@@ -558,6 +558,39 @@ class Builder(object):
 
         return ret
 
+    def build_single(self, blob, blobs, build_order):
+        self.indent_more()
+
+        # first pass: create builders for all blobs
+        builders = {}
+        for group in build_order:
+            for blob in group:
+                builder = self.create_blob_builder(blob)
+                builders[blob] = builder
+
+        # second pass: walk the build order blob by blob, mark blobs
+        # to be staged for their parents, but do not build them
+        ret = []
+        for group in build_order:
+            for blob in group:
+                built_items = builders[blob].builds()
+                for parent in blob.parents:
+                    stage_items = []
+                    for name, filename in built_items.items():
+                        self.msg('Marking %s to be staged for %s' %
+                                 (name, parent))
+                        stage_items.append((name, filename))
+
+                    parent_builder = builders[parent]
+                    parent_builder.stage_items.extend(stage_items)
+
+        # build the single blob now
+        ret.append(builders[blob].build())
+
+        self.indent_less()
+
+        return ret
+
     def create_blob_builder(self, blob):
         if isinstance(blob, morphlib.blobs.Stratum):
             builder = StratumBuilder(blob)