Python: Copy Python extractor to codeql repo

python/extractor/buildtools/discover.py

@@ -0,0 +1,65 @@
+import sys
+import os
+
+from buildtools import version
+
+DEFAULT_VERSION = 3
+
+def get_relative_root(root_identifiers):
+    if any([os.path.exists(identifier) for identifier in root_identifiers]):
+        print("Source root appears to be the real root.")
+        return "."
+
+    found = set()
+    for directory in next(os.walk("."))[1]:
+        if any([os.path.exists(os.path.join(directory, identifier)) for identifier in root_identifiers]):
+            found.add(directory)
+    if not found:
+        print("No directories containing root identifiers were found. Returning working directory as root.")
+        return "."
+    if len(found) > 1:
+        print("Multiple possible root directories found. Returning working directory as root.")
+        return "."
+
+    root = found.pop()
+    print("'%s' appears to be the root." % root)
+    return root
+
+def get_root(*root_identifiers):
+    return os.path.abspath(get_relative_root(root_identifiers))
+
+REQUIREMENTS_TAG = "LGTM_PYTHON_SETUP_REQUIREMENTS_FILES"
+
+def find_requirements(dir):
+    if REQUIREMENTS_TAG in os.environ:
+        val = os.environ[REQUIREMENTS_TAG]
+        if val == "false":
+            return []
+        paths = [ os.path.join(dir, line.strip()) for line in val.splitlines() ]
+        for p in paths:
+            if not os.path.exists(p):
+                raise IOError(p + " not found")
+        return paths
+    candidates = ["requirements.txt", "test-requirements.txt"]
+    return [ path if os.path.exists(path) else "" for path in [ os.path.join(dir, file) for file in  candidates] ]
+
+def discover(default_version=DEFAULT_VERSION):
+    """Discover things about the Python checkout and return a version, root, requirement-files triple."""
+    root = get_root("requirements.txt", "setup.py")
+    v = version.best_version(root, default_version)
+    # Unify the requirements or just get path to requirements...
+    requirement_files = find_requirements(root)
+    return v, root, requirement_files
+
+def get_version(default_version=DEFAULT_VERSION):
+    root = get_root("requirements.txt", "setup.py")
+    return version.best_version(root, default_version)
+
+def main():
+    if len(sys.argv) > 1:
+        print(discover(int(sys.argv[1])))
+    else:
+        print(discover())
+
+if __name__ == "__main__":
+    main()