Fixes #175: Dump environment provenance as well as build log.

lib/spack/spack/directory_layout.py

@@ -173,7 +173,9 @@ def __init__(self, root, **kwargs):
 
         self.spec_file_name      = 'spec.yaml'
         self.extension_file_name = 'extensions.yaml'
-        self.build_log_name      = 'build.out' # TODO: use config file.
+        self.build_log_name      = 'build.out'  # build log.
+        self.build_env_name      = 'build.env'  # build environment
+        self.packages_dir        = 'repos'      # archive of package.py files
 
         # Cache of already written/read extension maps.
         self._extension_maps = {}
@@ -231,6 +233,16 @@ def build_log_path(self, spec):
                          self.build_log_name)
 
 
+    def build_env_path(self, spec):
+        return join_path(self.path_for_spec(spec), self.metadata_dir,
+                         self.build_env_name)
+
+
+    def build_packages_path(self, spec):
+        return join_path(self.path_for_spec(spec), self.metadata_dir,
+                         self.packages_dir)
+
+
     def create_install_directory(self, spec):
         _check_concrete(spec)
 

lib/spack/spack/package.py

@@ -66,6 +66,7 @@
 from spack.stage import Stage, ResourceStage, StageComposite
 from spack.util.compression import allowed_archive, extension
 from spack.util.executable import ProcessError
+from spack.util.environment import dump_environment
 
 """Allowed URL schemes for spack packages."""
 _ALLOWED_URL_SCHEMES = ["http", "https", "ftp", "file", "git"]
@@ -884,10 +885,14 @@ def real_work():
                     # Do the real install in the source directory.
                     self.stage.chdir_to_source()
 
+                    # Save the build environment in a file before building.
+                    env_path = join_path(os.getcwd(), 'spack-build.env')
+
                     # This redirects I/O to a build log (and optionally to the terminal)
                     log_path = join_path(os.getcwd(), 'spack-build.out')
                     log_file = open(log_path, 'w')
                     with log_output(log_file, verbose, sys.stdout.isatty(), True):
+                        dump_environment(env_path)
                         self.install(self.spec, self.prefix)
 
                 # Ensure that something was actually installed.
@@ -896,7 +901,9 @@ def real_work():
                 # Move build log into install directory on success
                 if not fake:
                     log_install_path = spack.install_layout.build_log_path(self.spec)
+                    env_install_path = spack.install_layout.build_env_path(self.spec)
                     install(log_path, log_install_path)
+                    install(env_path, env_install_path)
 
                 # On successful install, remove the stage.
                 if not keep_stage:

lib/spack/spack/util/environment.py

@@ -63,3 +63,10 @@ def pop_keys(dictionary, *keys):
     for key in keys:
         if key in dictionary:
             dictionary.pop(key)
+
+
+def dump_environment(path):
+    """Dump the current environment out to a file."""
+    with open(path, 'w') as env_file:
+        for key,val in sorted(os.environ.items()):
+            env_file.write("%s=%s\n" % (key, val))