Attempt to create k8s venv without constraints if constraint build fa…

…ils (#26407)

There is an issue with trying to install the k8s env where the
current requirements conflict with constraints. The k8s env
creation is failing in this case.

This PR will not fail hard when the constraint-build fails, instead
it will attempt to build the venv without constraints. This will work
in vast majority of cases.

(cherry picked from commit 6f390fa)

dev/breeze/src/airflow_breeze/utils/kubernetes_utils.py

@@ -305,6 +305,38 @@ def _requirements_changed() -> bool:
     return False
 
 
+def _install_packages_in_k8s_virtualenv(dry_run: bool, verbose: bool, with_constraints: bool):
+    install_command = [
+        str(PYTHON_BIN_PATH),
+        "-m",
+        "pip",
+        "install",
+        "-r",
+        str(K8S_REQUIREMENTS.resolve()),
+    ]
+    if with_constraints:
+        install_command.extend(
+            [
+                "--constraint",
+                f"https://raw.githubusercontent.com/apache/airflow/{DEFAULT_AIRFLOW_CONSTRAINTS_BRANCH}/"
+                f"constraints-{sys.version_info.major}.{sys.version_info.minor}.txt",
+            ]
+        )
+    install_packages_result = run_command(
+        install_command,
+        verbose=verbose,
+        dry_run=dry_run,
+        check=False,
+        capture_output=True,
+    )
+    if install_packages_result.returncode != 0:
+        get_console().print(
+            f'[error]Error when updating pip to {PIP_VERSION}:[/]\n'
+            f'{install_packages_result.stdout}\n{install_packages_result.stderr}'
+        )
+    return install_packages_result
+
+
 def create_virtualenv(force: bool, verbose: bool, dry_run: bool) -> RunCommandResult:
     K8S_CLUSTERS_PATH.mkdir(parents=True, exist_ok=True)
     if not force and not _requirements_changed():
@@ -354,29 +386,17 @@ def create_virtualenv(force: bool, verbose: bool, dry_run: bool) -> RunCommandRe
         )
         return pip_reinstall_result
     get_console().print(f'[info]Installing necessary packages in {K8S_ENV_PATH}')
-    install_packages_result = run_command(
-        [
-            str(PYTHON_BIN_PATH),
-            "-m",
-            "pip",
-            "install",
-            "-r",
-            str(K8S_REQUIREMENTS.resolve()),
-            "--constraint",
-            f"https://raw.githubusercontent.com/apache/airflow/{DEFAULT_AIRFLOW_CONSTRAINTS_BRANCH}/"
-            f"constraints-{sys.version_info.major}.{sys.version_info.minor}.txt",
-        ],
-        verbose=verbose,
-        dry_run=dry_run,
-        check=False,
-        capture_output=True,
+
+    install_packages_result = _install_packages_in_k8s_virtualenv(
+        dry_run=dry_run, verbose=verbose, with_constraints=True
     )
     if install_packages_result.returncode != 0:
-        get_console().print(
-            f'[error]Error when updating pip to {PIP_VERSION}:[/]\n'
-            f'{install_packages_result.stdout}\n{install_packages_result.stderr}'
+        # if the first installation fails, attempt to install it without constraints
+        install_packages_result = _install_packages_in_k8s_virtualenv(
+            dry_run=dry_run, verbose=verbose, with_constraints=False
         )
-    CACHED_K8S_REQUIREMENTS.write_text(K8S_REQUIREMENTS.read_text())
+    if install_packages_result.returncode == 0:
+        CACHED_K8S_REQUIREMENTS.write_text(K8S_REQUIREMENTS.read_text())
     return install_packages_result