Larger hash space

openhands/runtime/utils/runtime_build.py

@@ -2,8 +2,10 @@
 import hashlib
 import os
 import shutil
+import string
 import tempfile
 from pathlib import Path
+from typing import List
 
 import docker
 from dirhash import dirhash
@@ -238,6 +240,19 @@ def prep_build_folder(
         file.write(dockerfile_content)  # type: ignore
 
 
+_ALPHABET = string.digits + string.ascii_lowercase
+
+
+def truncate_hash(hash: str) -> str:
+    """Convert the base16 hash to base36 and truncate at 16 characters."""
+    value = int(hash, 16)
+    result: List[str] = []
+    while value > 0 and len(result) < 16:
+        value, remainder = divmod(value, len(_ALPHABET))
+        result.append(_ALPHABET[remainder])
+    return ''.join(result)
+
+
 def get_hash_for_lock_files(base_image: str):
     openhands_source_dir = Path(openhands.__file__).parent
     md5 = hashlib.md5()

tests/unit/test_runtime_build.py

@@ -23,6 +23,7 @@
     get_runtime_image_repo,
     get_runtime_image_repo_and_tag,
     prep_build_folder,
+    truncate_hash,
 )
 
 OH_VERSION = f'oh_v{oh_version}'
@@ -522,3 +523,10 @@ def test_image_exists_not_found():
     mock_client.api.pull.assert_called_once_with(
         'nonexistent', tag='image', stream=True, decode=True
     )
+
+
+def test_truncate_hash():
+    truncated = truncate_hash('b08f254d76b1c6a7ad924708c0032251')
+    assert truncated == 'pma2wc71uq3c9a85'
+    truncated = truncate_hash('102aecc0cea025253c0278f54ebef078')
+    assert truncated == '4titk6gquia3taj5'