Create chunks, strata in cache via temporary files

This avoids problems with files with the right names but partial
content, if morph is killed in the middle of writing the file.

1 files changed, 13 insertions, 5 deletions

diff --git a/morphlib/builder.py b/morphlib/builder.py
index f08ae259..3a46cf54 100644
--- a/morphlib/builder.py
+++ b/morphlib/builder.py
@@ -66,6 +66,8 @@ class BlobBuilder(object):
         self.staging = None
         self.settings = None
         self.real_msg = None
+        self.cachedir = None
+        self.cache_basename = None
         self.cache_prefix = None
         self.tempdir = None
         self.logfile = None
@@ -168,8 +170,7 @@ class BlobBuilder(object):
 
     def write_cache_metadata(self, meta):
         self.msg('Writing metadata to the cache')
-        filename = '%s.meta' % self.cache_prefix
-        with open(filename, 'w') as f:
+        with self.cachedir.open(self.cache_basename + '.meta') as f:
             json.dump(meta, f, indent=4)
             f.write('\n')
 
@@ -432,9 +433,12 @@ class ChunkBuilder(BlobBuilder):
                 patterns = self.blob.chunks[chunk_name]
                 patterns += [r'baserock/%s\.' % chunk_name]
                 filename = self.filename(chunk_name)
+                basename = os.path.basename(filename)
                 self.msg('Creating binary for %s' % chunk_name)
-                morphlib.bins.create_chunk(self.destdir, filename, patterns,
-                                           self.ex, self.dump_memory_profile)
+                with self.cachedir.open(filename) as f:
+                    morphlib.bins.create_chunk(self.destdir, f, patterns,
+                                               self.ex, 
+                                               self.dump_memory_profile)
                 chunks.append((chunk_name, filename))
 
         files = os.listdir(self.destdir)
@@ -461,7 +465,9 @@ class StratumBuilder(BlobBuilder):
             self.prepare_binary_metadata(self.blob.morph.name)
             self.msg('Creating binary for %s' % self.blob.morph.name)
             filename = self.filename(self.blob.morph.name)
-            morphlib.bins.create_stratum(self.destdir, filename, ex)
+            basename = os.path.basename(filename)
+            with self.cachedir.open(basename) as f:
+                morphlib.bins.create_stratum(self.destdir, f, ex)
         return { self.blob.morph.name: filename }
 
 
@@ -712,7 +718,9 @@ class Builder(object):
         builder.destdir = os.path.join(s, '%s.inst' % blob.morph.name)
         builder.settings = self.settings
         builder.real_msg = self.msg
+        builder.cachedir = self.cachedir
         builder.cache_prefix = self.cachedir.name(cache_id)
+        builder.cache_basename = os.path.basename(builder.cache_prefix)
         builder.tempdir = self.tempdir
         builder.dump_memory_profile = self.dump_memory_profile