Add Multi-version Capability

Adds support for having multiple evaluation python versions installed in
the docker container. A utility to automatically generate correct
dockerfile instructions and nsjail mounts based on the available
versions is also included.

Signed-off-by: Hassan Abouelela <[email protected]>

1 files changed, 54 insertions, 0 deletions

diff --git a/scripts/python_version.py b/scripts/python_version.py
new file mode 100644
index 0000000..6c8f25c
--- /dev/null
+++ b/scripts/python_version.py
@@ -0,0 +1,54 @@
+"""
+Parse and return python version information from the versions file.
+
+The version file is read from the environment variable VERSIONS_CONFIG,
+and defaults to config/versions.json otherwise.
+"""
+
+import json
+import os
+from dataclasses import dataclass
+from pathlib import Path
+
+VERSIONS_FILE = Path(os.getenv("VERSIONS_CONFIG", "config/versions.json"))
+
+
+@dataclass(frozen=True)
+class Version:
+    """A python image available for eval."""
+
+    image_tag: str
+    version_name: str
+    display_name: str
+    is_main: bool
+
+
+_ALL_VERSIONS = None
+_MAIN_VERSION = None
+
+
+def get_all_versions() -> tuple[list[Version], Version]:
+    """
+    Get a list of all available versions for this evaluation.
+
+    Returns a tuple of all versions, and the main version.
+    """
+    # Return a cached result
+    global _ALL_VERSIONS, _MAIN_VERSION
+    if _ALL_VERSIONS is not None:
+        return _ALL_VERSIONS, _MAIN_VERSION
+
+    versions = []
+    main_version: Version | None = None
+
+    for version_json in json.loads(VERSIONS_FILE.read_text("utf-8")):
+        version = Version(**version_json)
+        if version.is_main:
+            main_version = version
+        versions.append(version)
+
+    if main_version is None:
+        raise Exception("Exactly one version must be configured as the main version.")
+
+    _ALL_VERSIONS, _MAIN_VERSION = versions, main_version
+    return versions, main_version