diff --git a/obal/data/modules/build_source.py b/obal/data/modules/build_source.py
new file mode 100644
index 00000000..8c084353
--- /dev/null
+++ b/obal/data/modules/build_source.py
@@ -0,0 +1,97 @@
+"""
+Build a source package
+"""
+
+import os
+import re
+from contextlib import contextmanager
+from glob import glob
+from subprocess import CalledProcessError, check_output
+
+from ansible.module_utils.basic import AnsibleModule
+
+
+@contextmanager
+def chdir(directory):
+    """
+    Change the directory in a context manager. Automatically switches back even if an exception
+    occurs.
+    """
+    old = os.getcwd()
+    os.chdir(directory)
+    try:
+        yield
+    finally:
+        os.chdir(old)
+
+
+def main():
+    """
+    Build a source package
+    """
+    module = AnsibleModule(
+        argument_spec=dict(
+            directory=dict(required=True),
+        )
+    )
+
+    directory = module.params['directory']
+    path = None
+
+    with chdir(directory):
+        if os.path.exists(os.path.join(directory, 'Rakefile.dist')):
+            try:
+                output = check_output(['rake', '-f', 'Rakefile.dist', 'pkg:generate_source'],
+                                      universal_newlines=True).rstrip()
+            except CalledProcessError as error:
+                module.fail_json(msg='Failed to build using Rakefile.dist',
+                                 stdout=error.stdout, stderr=error.stderr)
+            if not output:
+                module.fail_json(msg='Failed to determine the output file')
+            path = output.splitlines()[-1]
+        elif glob(os.path.join(directory, '*.gemspec')):
+            gemspecs = glob(os.path.join(directory, '*.gemspec'))
+            if len(gemspecs) != 1:
+                gemspec = os.path.join(directory, os.path.basename(directory) + '.gemspec')
+                if gemspec not in gemspecs:
+                    module.fail_json(msg='Multiple gemspecs found', gemspecs=gemspecs)
+            else:
+                gemspec = gemspecs[0]
+
+            try:
+                # TODO: use --output to set the path?
+                output = check_output(['gem', 'build', gemspec], universal_newlines=True)
+            except CalledProcessError as error:
+                module.fail_json(msg='Failed to build gemspec', gemspec=gemspec,
+                                 stdout=error.stdout, stderr=error.stderr)
+
+            match = re.search(r'File: (?P<path>.+\.gem)', output)
+            if not match:
+                module.fail_json(msg='Failed to determine gem file from output', output=output,
+                                 gemspec=gemspec)
+            path = match.group('path')
+        elif os.path.exists('Rakefile'):
+            # TODO: bundle install?
+            try:
+                output = check_output(['bundle', 'exec', 'rake', 'pkg:generate_source'],
+                                      universal_newlines=True).rstrip()
+            except CalledProcessError as error:
+                module.fail_json(msg='Failed to build using Rakefile.dist',
+                                 stdout=error.stdout, stderr=error.stderr)
+            if not output:
+                module.fail_json(msg='Failed to determine the output file')
+            path = output.splitlines()[-1]
+        else:
+            module.fail_json(msg='Unsupported package directory')
+
+    if not os.path.isabs(path):
+        path = os.path.join(directory, path)
+
+    if not os.path.exists(path):
+        module.fail_json(msg="Determined path doesn't exist", path=path)
+
+    module.exit_json(changed=path is not None, path=path)
+
+
+if __name__ == '__main__':
+    main()