cosabuild/build.py: Tweak variable names

Use `builds_dir` instead of `build_dir` to refer to `builds/`, and
`build_dir` instead of `build_root` to refer to `builds/$id/`. This
matches the convention used in the rest of the codebase.

src/cmd-koji-upload

@@ -128,8 +128,8 @@ class Build(_Build):
         """
         # locate all the build artifacts in the build directory.
         files = []
-        for ffile in os.listdir(self.build_root):
-            files.append(os.path.join(self.build_root, ffile))
+        for ffile in os.listdir(self.build_dir):
+            files.append(os.path.join(self.build_dir, ffile))
             if os.path.islink(ffile):
                 log.debug(" * EXCLUDING symlink '%s'", ffile)
                 log.debug(" *    target '%s'", os.path.realpath(ffile))

src/cosalib/build.py

@@ -55,6 +55,7 @@ def write_json(path, data):
     os.fchmod(f.file.fileno(), 0o644)
     os.rename(f.name, path)
 
+
 class _Build:
     """
     The Build Class handles the reading in and return of build JSON emitted
@@ -64,13 +65,13 @@ class _Build:
       - _build_artifacts(*args, **kwargs)
     """
 
-    def __init__(self, build_dir, build="latest", workdir=None):
+    def __init__(self, builds_dir, build="latest", workdir=None):
         """
         init loads the builds.json which lists the builds, loads the relevant
         meta-data from JSON and finally, locates the build artifacts.
 
-        :param build_dir: name of directory to find the builds
-        :type build_dir: str
+        :param builds_dir: name of directory to find the builds
+        :type builds_dir: str
         :param build: build id or "latest" to parse
         :type build: str
         :param workdir: Temporary directory to ensure exists and is clean
@@ -83,15 +84,15 @@ def __init__(self, build_dir, build="latest", workdir=None):
         If workdir is None then no temporary work directory is created.
         """
         log.info('Evaluating builds.json')
-        builds = load_json('%s/builds.json' % build_dir)
+        builds = load_json('%s/builds.json' % builds_dir)
         if build != "latest":
             if build not in builds['builds']:
                 raise BuildError("Build was not found in builds.json")
         else:
             build = builds['builds'][0]
 
         log.info("Targeting build: %s", build)
-        self._build_root = os.path.abspath("%s/%s" % (build_dir, build))
+        self._build_dir = os.path.abspath("%s/%s" % (builds_dir, build))
 
         self._build_json = {
             "commit": None,
@@ -155,9 +156,9 @@ def build_id(self):
         return self.get_meta_key("meta", "buildid")
 
     @property
-    def build_root(self):
+    def build_dir(self):
         """ return the actual path for the build root """
-        return self._build_root
+        return self._build_dir
 
     @property
     def build_name(self):
@@ -220,11 +221,10 @@ def __file(self, var):
         :raises: KeyError
         """
         lookup = {
-            "commit": "%s/commitmeta.json" % self.build_root,
-            "config": ("%s/coreos-assembler-config-git.json" %
-                       self.build_root),
+            "commit": "%s/commitmeta.json" % self.build_dir,
+            "config": ("%s/coreos-assembler-config-git.json" % self.build_dir),
             "image": "/cosa/coreos-assembler-git.json",
-            "meta": "%s/meta.json" % self.build_root,
+            "meta": "%s/meta.json" % self.build_dir,
         }
         return lookup[var]