CLOUDP-295785 - copy kubectl-mongodb plugin to ./bin/kubectl-mongodb for code snippets tests (#565)

# Summary

We need to make `kubectl-mongodb` available for Code Snippets tests.
Previously Code Snippets were expecting the binary in `./bin` directory,
but this logic was lost when the `kubectl-mongodb` build process was
changed.


https://github.com/mongodb/mongodb-kubernetes/blob/d40621c8126ea38cc38cfaec104fb7226430a941/scripts/evergreen/build_multi_cluster_kubeconfig_creator.sh#L38-L40

This PR brings back this copy procedure to make Code Snippets tests
work. Additionally changed the logic of `download_multi_cluster_binary`
evergreen function and now it only downloads single binary matching
platform provided - there is no need to download all platform variants.

## Proof of Work

Passing CI and run the test locally:

```
(venv) ➜  mongodb-kubernetes git:(maciejk/ar-fix-kubectl-plugin-location) ✗ scripts/dev/run_python.sh scripts/release/kubectl_mongodb/download_kubectl_plugin.py --build-scenario staging --version b478944 --platform linux/amd64
INFO     2025-10-31 13:05:44,644 [download_kubectl_plugin]  Downloading s3://mongodb-kubernetes-staging/kubectl-mongodb/b4789443/kubectl-mongodb_linux_amd64 to docker/mongodb-kubernetes-tests/multi-cluster-kube-config-creator_amd64
INFO     2025-10-31 13:05:46,472 [download_kubectl_plugin]  Successfully downloaded artifact to docker/mongodb-kubernetes-tests/multi-cluster-kube-config-creator_amd64 and bin/kubectl-mongodb
```

## Checklist

- [x] Have you linked a jira ticket and/or is the ticket in the title?
- [x] Have you checked whether your jira ticket required DOCSP changes?
- [x] Have you added changelog file?
    - use `skip-changelog` label if not needed
- refer to [Changelog files and Release
Notes](https://github.com/mongodb/mongodb-kubernetes/blob/master/CONTRIBUTING.md#changelog-files-and-release-notes)
section in CONTRIBUTING.md for more details

Author: MaciejKaras

.evergreen-functions.yml

@@ -525,6 +525,8 @@ functions:
       params:
         working_dir: src/github.com/mongodb/mongodb-kubernetes
         binary: scripts/release/kubectl_mongodb/download_kubectl_plugin.sh
+        env:
+          PLATFORM: ${platform}
 
   pipeline:
     - command: subprocess.exec

.evergreen-snippets.yml

@@ -7,7 +7,10 @@ variables:
       - func: setup_mongosh
       - func: download_kube_tools
       - func: switch_context
+      - func: python_venv
       - func: download_multi_cluster_binary
+        vars:
+          platform: linux/amd64
     teardown_task:
       - func: upload_e2e_logs
       - func: upload_code_snippets_logs

.evergreen.yml

@@ -358,6 +358,8 @@ tasks:
       - func: clone
       - func: setup_building_host
       - func: download_multi_cluster_binary
+        vars:
+          platform: linux/amd64
       - func: pipeline
         vars:
           image_name: meko-tests
@@ -367,6 +369,8 @@ tasks:
       - func: clone
       - func: setup_building_host
       - func: download_multi_cluster_binary
+        vars:
+          platform: linux/arm64
       - func: pipeline
         vars:
           image_name: meko-tests-arm64
@@ -379,6 +383,8 @@ tasks:
           skip_minikube_setup: true
           skip_install_python_requirements: false
       - func: download_multi_cluster_binary
+        vars:
+          platform: linux/s390x
       - func: pipeline
         vars:
           image_name: meko-tests-ibm-z
@@ -391,6 +397,8 @@ tasks:
           skip_minikube_setup: true
           skip_install_python_requirements: false
       - func: download_multi_cluster_binary
+        vars:
+          platform: linux/ppc64le
       - func: pipeline
         vars:
           image_name: meko-tests-ibm-power

scripts/release/kubectl_mongodb/download_kubectl_plugin.py

@@ -1,28 +1,34 @@
 import argparse
 import os
+import shutil
 
 from botocore.exceptions import ClientError
 
 from lib.base_logger import logger
-from scripts.release.argparse_utils import get_platforms_from_arg, get_scenario_from_arg
+from scripts.release.argparse_utils import get_scenario_from_arg
 from scripts.release.build.build_info import (
     KUBECTL_PLUGIN_BINARY,
     load_build_info,
 )
 from scripts.release.build.build_scenario import SUPPORTED_SCENARIOS, BuildScenario
+from scripts.release.build.image_build_configuration import SUPPORTED_PLATFORMS
 from scripts.release.kubectl_mongodb.build_kubectl_plugin import (
     kubectl_plugin_name,
     parse_platform,
     s3_path,
 )
 from scripts.release.kubectl_mongodb.utils import create_s3_client
 
+KUBECTL_MONGODB_PLUGIN_BIN_PATH = "bin/kubectl-mongodb"
+
 
 def local_tests_plugin_path(arch_name: str) -> str:
     return f"docker/mongodb-kubernetes-tests/multi-cluster-kube-config-creator_{arch_name}"
 
 
-def download_kubectl_plugin_from_s3(s3_bucket: str, s3_plugin_path: str, local_path: str):
+def download_kubectl_plugin_from_s3(
+    s3_bucket: str, s3_plugin_path: str, local_path: str, copy_to_bin_path: bool = False
+) -> None:
     """
     Downloads the plugin for provided platform and puts it in the path expected by the tests image
     """
@@ -35,7 +41,12 @@ def download_kubectl_plugin_from_s3(s3_bucket: str, s3_plugin_path: str, local_p
         # change the file's permissions to make file executable
         os.chmod(local_path, 0o755)
 
-        logger.info(f"Successfully downloaded artifact to {local_path}")
+        if copy_to_bin_path:
+            shutil.copyfile(local_path, KUBECTL_MONGODB_PLUGIN_BIN_PATH)
+
+        logger.info(
+            f"Successfully downloaded artifact to {local_path}{f" and {KUBECTL_MONGODB_PLUGIN_BIN_PATH}" if copy_to_bin_path else ""}"
+        )
     except ClientError as e:
         if e.response["Error"]["Code"] == "404":
             raise Exception(f"Artifact not found at s3://{s3_bucket}/{s3_plugin_path}: {e}")
@@ -74,28 +85,25 @@ def main():
         "--platform",
         metavar="",
         action="store",
+        required=True,
         type=str,
-        help="Override the platforms instead of resolving from build scenario. Multi-arch builds are comma-separated. Example: linux/amd64,linux/arm64",
+        choices=SUPPORTED_PLATFORMS,
+        help=f"Specify kubectl-mongodb plugin platform to download. Options: {", ".join(SUPPORTED_PLATFORMS)}.",
     )
     args = parser.parse_args()
 
     build_scenario = get_scenario_from_arg(args.build_scenario)
     build_info = load_build_info(build_scenario).binaries[KUBECTL_PLUGIN_BINARY]
 
-    platforms = get_platforms_from_arg(args.platform) or build_info.platforms
+    platform = args.platform
     version = args.version
 
-    for platform in platforms:
-        os_name, arch_name = parse_platform(platform)
-        if os_name != "linux":
-            logger.debug(f"Skipping non-linux platform {platform}, not used in e2e tests in Evergreen CI")
-            continue
-
-        filename = kubectl_plugin_name(os_name, arch_name)
-        s3_plugin_path = s3_path(filename, version)
-        local_path = local_tests_plugin_path(arch_name)
+    os_name, arch_name = parse_platform(platform)
+    filename = kubectl_plugin_name(os_name, arch_name)
+    s3_plugin_path = s3_path(filename, version)
+    local_path = local_tests_plugin_path(arch_name)
 
-        download_kubectl_plugin_from_s3(build_info.s3_store, s3_plugin_path, local_path)
+    download_kubectl_plugin_from_s3(build_info.s3_store, s3_plugin_path, local_path, copy_to_bin_path=True)
 
 
 if __name__ == "__main__":

scripts/release/kubectl_mongodb/download_kubectl_plugin.sh

@@ -4,4 +4,4 @@ set -Eeou pipefail
 
 source scripts/dev/set_env_context.sh
 
-scripts/dev/run_python.sh scripts/release/kubectl_mongodb/download_kubectl_plugin.py --build-scenario "${BUILD_SCENARIO}" --version "${OPERATOR_VERSION}"
+scripts/dev/run_python.sh scripts/release/kubectl_mongodb/download_kubectl_plugin.py --build-scenario "${BUILD_SCENARIO}" --version "${OPERATOR_VERSION}" --platform "${PLATFORM}"