Allow for flytekit version to be specified in default image builder

flytekit/image_spec/default_builder.py

@@ -1,5 +1,6 @@
 import json
 import os
+import re
 import shutil
 import subprocess
 import sys
@@ -98,11 +99,25 @@
         return f"flytekit=={__version__}"
 
 
+_PACKAGE_NAME_RE = re.compile(r"^[\w-]+")
+
+
+def _is_flytekit(package: str) -> bool:
+    """Return True if `package` is flytekit. `package` is expected to be a valid version
+    spec. i.e. `flytekit==1.12.3`, `flytekit`, `flytekit~=1.12.3`.
+    """
+    m = _PACKAGE_NAME_RE.match(package)
+    if not m:
+        return False
+    name = m.group()
+    return name == "flytekit"
+
+
 def create_docker_context(image_spec: ImageSpec, tmp_dir: Path):
     """Populate tmp_dir with Dockerfile as specified by the `image_spec`."""
     base_image = image_spec.base_image or "debian:bookworm-slim"
 
-    requirements = [get_flytekit_for_pypi()]
+    requirements = []
 
     if image_spec.cuda is not None or image_spec.cudnn is not None:
         msg = (
@@ -124,6 +139,10 @@
     if image_spec.packages:
         requirements.extend(image_spec.packages)
 
+    # Adds flytekit if it is not specified
+    if not any(_is_flytekit(package) for package in requirements):
+        requirements.append(get_flytekit_for_pypi())
+
     uv_requirements = []
 
     # uv does not support git + subdirectory, so we use pip to install them instead

tests/flytekit/unit/core/image_spec/test_default_builder.py

@@ -2,6 +2,7 @@
 
 import pytest
 
+import flytekit
 from flytekit.image_spec import ImageSpec
 from flytekit.image_spec.default_builder import DefaultImageBuilder, create_docker_context
 
@@ -99,6 +100,41 @@ def test_create_docker_context_with_null_entrypoint(tmp_path):
     assert "ENTRYPOINT []" in dockerfile_content
 
 
+@pytest.mark.parametrize("flytekit_spec", [None, "flytekit>=1.12.3", "flytekit==1.12.3"])
+def test_create_docker_context_with_flytekit(tmp_path, flytekit_spec, monkeypatch):
+
+    # pretend version is 1.13.0
+    mock_version = "1.13.0"
+    monkeypatch.setattr(flytekit, "__version__", mock_version)
+
+    docker_context_path = tmp_path / "builder_root"
+    docker_context_path.mkdir()
+
+    if flytekit_spec:
+        packages = [flytekit_spec]
+    else:
+        packages = []
+
+    image_spec = ImageSpec(
+        name="FLYTEKIT", packages=packages
+    )
+
+    create_docker_context(image_spec, docker_context_path)
+
+    dockerfile_path = docker_context_path / "Dockerfile"
+    assert dockerfile_path.exists()
+
+    requirements_path = docker_context_path / "requirements_uv.txt"
+    assert requirements_path.exists()
+
+    requirements_content = requirements_path.read_text()
+    if flytekit_spec:
+        flytekit_spec in requirements_content
+        assert f"flytekit=={mock_version}" not in requirements_content
+    else:
+        assert f"flytekit=={mock_version}" in requirements_content
+
+
 def test_create_docker_context_cuda(tmp_path):
     docker_context_path = tmp_path / "builder_root"
     docker_context_path.mkdir()