Trade-offs in AWS S3

tensor9 explain \
  -origin aws::1.0.0::s3 \
  -target google::1.0.0::gcs \
  -fmt Human

tensor9 adapt svc run \
  --origin aws::1.0.0::s3 \
  --backend google::1.0.0::gcs

export AWS_ENDPOINT_URL_S3="<endpoint printed by tensor9>"
export AWS_PROFILE="adapter-test"
export AWS_REGION="us-east-1"
export AWS_REQUEST_CHECKSUM_CALCULATION="WHEN_REQUIRED"
python3 -m venv .venv-s3-tradeoffs
source .venv-s3-tradeoffs/bin/activate
python -m pip install boto3

import json
import sys
from pathlib import Path
import boto3
from botocore.exceptions import ClientError

s3 = boto3.client("s3", endpoint_url="<endpoint printed by tensor9>",
                  region_name="us-east-1")
bucket = "tradeoffs-media"
key = "version-check/report.txt"
record = Path("s3-version-check.json")
mode = sys.argv[1]

if mode == "write":
    if record.exists():
        raise RuntimeError("An earlier test record exists; inspect it first")
    existing = s3.list_object_versions(Bucket=bucket, Prefix=key)
    if any(v["Key"] == key for v in
           existing.get("Versions", []) + existing.get("DeleteMarkers", [])):
        raise RuntimeError("The test key already has history; use an empty test bucket")
    state = {"bucket": bucket, "key": key, "versions": []}
    record.write_text(json.dumps(state))
    for body in (b"report A\n", b"report B\n"):
        result = s3.put_object(Bucket=bucket, Key=key, Body=body)
        version = result.get("VersionId")
        if not version or version == "null":
            raise RuntimeError("No version identity; inspect bucket configuration")
        state["versions"].append(version)
        record.write_text(json.dumps(state))
    deleted = s3.delete_object(Bucket=bucket, Key=key)
    state["marker"] = deleted.get("VersionId")
    record.write_text(json.dumps(state))
    assert deleted.get("DeleteMarker") is True and state["marker"]
elif mode not in ("verify", "cleanup"):
    raise ValueError("Choose write, verify or cleanup")

state = json.loads(record.read_text())
assert state["bucket"] == bucket and state["key"] == key
if mode == "cleanup":
    for version in state["versions"] + [state.get("marker")]:
        if version:
            s3.delete_object(Bucket=bucket, Key=key, VersionId=version)
    print("Removed only the recorded versions and marker; retain the record")
else:
    assert len(state["versions"]) == len(set(state["versions"])) == 2
    for version, expected in zip(state["versions"], (b"report A\n", b"report B\n")):
        response = s3.get_object(Bucket=bucket, Key=key, VersionId=version)
        try:
            assert response["Body"].read() == expected
        finally:
            response["Body"].close()
    try:
        s3.get_object(Bucket=bucket, Key=key)
    except ClientError as error:
        assert error.response["ResponseMetadata"]["HTTPStatusCode"] == 404
    else:
        raise AssertionError("Current key is visible after its delete marker")
    print("Both named versions match; the current key is deleted")