download: add shared feature

slapos/recipe/download.py

@@ -28,6 +28,8 @@ import errno
 import os
 import shutil
 import zc.buildout
+import logging
+from hashlib import md5
 
 class Recipe(object):
   _parts = None
@@ -38,17 +40,45 @@ class Recipe(object):
       hash_name=True)
     self._url = options['url']
     self._md5sum = options.get('md5sum')
+    self._name = name
     mode = options.get('mode')
+    log = logging.getLogger(name)
     if mode is not None:
       mode = int(mode, 8)
     self._mode = mode
     if 'filename' in options and 'destination' in options:
       raise zc.buildout.UserError('Parameters filename and destination are '
         'exclusive.')
+
     destination = options.get('destination', None)
     if destination is None:
+      shared = options.get('shared')
+      self._shared = shared
+      if shared:
+        shared_part = buildout['buildout'].get('shared-part', None)
+        if not shared_part:
+          raise ValueError(
+            " Set ${buildout:shared-part} for shared feature")
+
+        shared = os.path.join(shared_part.strip().rstrip('/'), name)
+        if not os.path.exists(shared):
+          os.makedirs(shared)
+        self._debug_signature_text = []
+        m = md5()
+        profile_base_location = options.get('_profile_base_location_', '')
+        for k, v in sorted(options.items()):
+          if profile_base_location:
+            v = v.replace(profile_base_location, '${:_profile_base_location_}')
+          option_signature = ('%r: %r' % (k, v)).encode()
+          self._debug_signature_text.append(option_signature)
+          m.update(option_signature)
+        shared = os.path.join(shared, m.hexdigest())
+        self._parts = parts = shared
+        log.info('shared directory  %s set for %s' % (shared, name))
+      else:
         self._parts = parts = os.path.join(buildout_section['parts-directory'],
           name)
+
       destination = os.path.join(parts, options.get('filename', name))
       # Compatibility with other recipes: expose location
       options['location'] = parts
@@ -58,6 +88,13 @@ class Recipe(object):
     destination = self._destination
     result = [destination]
     parts = self._parts
+    log = logging.getLogger(self._name)
+    if self._shared:
+      log.info('Checking whether package is installed at shared path: %s' % destination)
+      if os.path.exists(destination):
+        log.info('This shared package has been installed by other package')
+        return []
+
     if parts is not None and not os.path.isdir(parts):
       os.mkdir(parts)
       result.append(parts)
@@ -74,6 +111,10 @@ class Recipe(object):
         if self._mode is not None:
           os.fchmod(fdst.fileno(), self._mode)
         shutil.copyfileobj(fsrc, fdst)
+
+    if self._shared:
+      with open(os.path.join(parts, ".slapos.recipe.build.signature"), 'w') as f:
+        f.write('\n'.join(self._debug_signature_text))
     return result
 
   def update(self):