Command args to generate build file without building the package (#85)

#### Command args to generate build file without building the package

This addition supports a common pattern: generating a build file for a
collection of sources then editing that build file (e.g. to specify
package format or per-source transforms) before building a package.

Making generate (a build-file from source) a separate command instead
of making it an option for quilt build. Generate doesn’t actually build
a package so it doesn’t need a package name.

Also renaming the directory (-d) option in quilt build to auto (-a).

quilt/test/test_command.py

@@ -4,9 +4,10 @@
 
 import json
 import os
+import time
+
 import pytest
 import responses
-import time
 
 from six import assertRaisesRegex
 
@@ -145,3 +146,14 @@ def _mock_logs_list(self, owner, package, pkg_hash):
             author=owner)])
         print("MOCKING URL=%s" % logs_url)
         self.requests_mock.add(responses.GET, logs_url, json.dumps(resp))
+
+    def test_generate_buildfile_wo_building(self):
+        mydir = os.path.dirname(__file__)
+        path = os.path.join(mydir, 'data')
+        buildfilepath = os.path.join(path, 'build.yml')
+        assert not os.path.exists(buildfilepath), "%s already exists" % buildfilepath
+        try:
+            command.generate(path)
+            assert os.path.exists(buildfilepath), "failed to create %s" % buildfilepath
+        finally:
+            os.remove(buildfilepath)

quilt/tools/build.py

@@ -50,7 +50,8 @@ def _build_node(build_dir, package, name, node, target='pandas'):
         ID = 'id'
         if transform:
             if (transform not in TARGET[target]) and (transform != ID):
-                raise BuildException("Unknown transform '%s' for %s @ %s" % (transform, rel_path, target))
+                raise BuildException("Unknown transform '%s' for %s @ %s" %
+                                     (transform, rel_path, target))
         else: # guess transform if user doesn't provide one
             ignore, ext = splitext_no_dot(rel_path)
             ext = ext.lower()
@@ -179,7 +180,7 @@ def _generate_contents(dir_path):
         contents = {}
 
         for name in os.listdir(dir_path):
-            if name.startswith('.') or name == PACKAGE_DIR_NAME:
+            if name.startswith('.') or name == PACKAGE_DIR_NAME or name == outfilename:
                 continue
 
             path = os.path.join(dir_path, name)
@@ -207,10 +208,14 @@ def _generate_contents(dir_path):
 
         return contents
 
+    buildfilepath = os.path.join(startpath, outfilename)
+    if os.path.exists(buildfilepath):
+        raise BuildException("Build file %s already exists." % buildfilepath)
+
     contents = dict(
         contents=_generate_contents(startpath)
     )
-    buildfilepath = os.path.join(startpath, outfilename)
+
     with open(buildfilepath, 'w') as outfile:
         yaml.dump(contents, outfile, default_flow_style=False)
     return buildfilepath

quilt/tools/command.py

@@ -181,14 +181,29 @@ def logout():
     else:
         print("Already logged out.")
 
-def build(package, path, directory=None):
+def generate(directory):
+    """
+    Generate a build-file for quilt build from a directory of
+    source files.
+    """
+    try:
+        buildfilepath = generate_build_file(directory)
+    except BuildException as builderror:
+        raise CommandException(str(builderror))
+
+    print("Generated build-file %s." % (buildfilepath))
+
+def build(package, path, auto=None):
     """
     Compile a Quilt data package
     """
     owner, pkg = _parse_package(package)
+    directory = auto
     if directory:
-        buildfilepath = generate_build_file(directory)
-        buildpath = buildfilepath
+        try:
+            buildpath = generate_build_file(directory)
+        except BuildException as builderror:
+            raise CommandException(str(builderror))
     else:
         buildpath = path
 

quilt/tools/main.py

@@ -29,10 +29,14 @@ def main():
     log_p.add_argument("package", type=str, help="Owner/Package Name")
     log_p.set_defaults(func=command.log)
 
+    generate_p = subparsers.add_parser("generate")
+    generate_p.add_argument("directory", help="Source file directory")
+    generate_p.set_defaults(func=command.generate)
+
     build_p = subparsers.add_parser("build")
     build_p.add_argument("package", type=str, help="Owner/Package Name")
     buildpath_group = build_p.add_mutually_exclusive_group(required=True)
-    buildpath_group.add_argument("-d", "--directory", type=str, help="Source file directory")
+    buildpath_group.add_argument("-a", "--auto", type=str, help="Source file directory")
     buildpath_group.add_argument("path", type=str, nargs='?', help="Path to the Yaml build file")
     build_p.set_defaults(func=command.build)