⚡️ Speed up method S3DataSource.generate_presigned_url by 6%

[codeflash-ai]

📄 6% (0.06x) speedup for S3DataSource.generate_presigned_url in backend/python/app/sources/external/s3/s3.py

⏱️ Runtime : 2.25 milliseconds → 2.11 milliseconds (best of 227 runs)

📝 Explanation and details

The optimized code achieves a 6% runtime improvement and 0.9% throughput improvement through a session caching optimization in the generate_presigned_url method.

Key Optimization:

• Session lookup shortcut: Changed session = await self._get_aioboto3_session() to session = self._session or await self._get_aioboto3_session()
• This avoids the async function call overhead when the session is already cached (which is the common case after the first invocation)

Performance Impact:
The line profiler shows the dramatic improvement - _get_aioboto3_session calls dropped from 1,098 hits to just 26 hits, reducing total time in that function from 451,726ns to 59,241ns (87% reduction). The session acquisition line in generate_presigned_url improved from 3.13ms to 0.416ms per hit.

Why This Works:
After the initial session creation, self._session is cached. The optimization uses Python's short-circuit evaluation (or) to return the cached session directly without the async function call overhead. This eliminates unnecessary async context switches and function call overhead for the majority of requests.

Best for:

• High-throughput scenarios with repeated calls (as shown in throughput tests with 100-250 concurrent requests)
• Applications where the same S3DataSource instance handles multiple presigned URL requests
• Production workloads where the session is established early and reused frequently

The optimization maintains all original functionality and error handling while providing consistent performance gains across all test scenarios.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 1126 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	83.3%

🌀 Generated Regression Tests and Runtime

import asyncio  # used to run async functions
from typing import Any, Dict, Optional

import pytest  # used for our unit tests
from app.sources.external.s3.s3 import S3DataSource


class S3RESTClientViaAccessKey:
    """Mock for S3RESTClientViaAccessKey, returns a session."""
    def get_session(self):
        return MockAioBoto3Session()

class S3Client:
    """Mock S3Client for testing."""
    def __init__(self, client):
        self.client = client

    def get_session(self):
        return self.client.get_session()

class MockAioBoto3Session:
    """Mock aioboto3.Session for testing."""
    def client(self, service_name):
        return MockS3Client()

class MockS3Client:
    """Mock async context manager for S3 client."""
    async def __aenter__(self):
        return self

    async def __aexit__(self, exc_type, exc, tb):
        pass

    async def generate_presigned_url(self, **kwargs):
        # Simulate valid presigned URL generation for basic cases
        # For edge cases, we can inject behaviors via kwargs for tests
        method = kwargs.get('ClientMethod')
        params = kwargs.get('Params')
        expires_in = kwargs.get('ExpiresIn')
        http_method = kwargs.get('HttpMethod')

        # Simulate error for specific test cases
        if method == "invalid_method":
            raise MockClientError({"Error": {"Code": "InvalidMethod", "Message": "Method not supported"}})
        if params == {"cause_error": True}:
            raise MockClientError({"Error": {"Code": "BadParams", "Message": "Params error"}})
        if expires_in == -1:
            raise Exception("Negative expiration not allowed")
        # Simulate a large response for large scale tests
        if params and params.get("large_test"):
            return {"url": "https://example.com/large", "extra": "x" * 500}

        # Default: return a mock URL string
        return "https://example.com/presigned-url"

class MockClientError(Exception):
    """Mock ClientError for testing."""
    def __init__(self, response):
        self.response = response


# --- Unit Tests ---

@pytest.fixture
def s3_data_source():
    """Fixture to provide a S3DataSource instance with mock client."""
    client = S3RESTClientViaAccessKey()
    s3_client = S3Client(client)
    return S3DataSource(s3_client)

# 1. Basic Test Cases

@pytest.mark.asyncio
async def test_generate_presigned_url_basic_success(s3_data_source):
    """Test basic successful presigned URL generation."""
    response = await s3_data_source.generate_presigned_url(
        ClientMethod="get_object",
        Params={"Bucket": "my-bucket", "Key": "my-key"},
        ExpiresIn=3600,
        HttpMethod="GET"
    )

@pytest.mark.asyncio
async def test_generate_presigned_url_basic_minimal_params(s3_data_source):
    """Test presigned URL generation with only required parameter."""
    response = await s3_data_source.generate_presigned_url(ClientMethod="get_object")

@pytest.mark.asyncio
async def test_generate_presigned_url_basic_optional_params_none(s3_data_source):
    """Test presigned URL generation with all optional params as None."""
    response = await s3_data_source.generate_presigned_url(
        ClientMethod="get_object",
        Params=None,
        ExpiresIn=None,
        HttpMethod=None
    )

# 2. Edge Test Cases

@pytest.mark.asyncio
async def test_generate_presigned_url_invalid_method_error(s3_data_source):
    """Test error handling for invalid ClientMethod."""
    response = await s3_data_source.generate_presigned_url(ClientMethod="invalid_method")

@pytest.mark.asyncio
async def test_generate_presigned_url_params_error(s3_data_source):
    """Test error handling for bad Params."""
    response = await s3_data_source.generate_presigned_url(
        ClientMethod="get_object",
        Params={"cause_error": True}
    )

@pytest.mark.asyncio
async def test_generate_presigned_url_negative_expires_in(s3_data_source):
    """Test error handling for negative ExpiresIn."""
    response = await s3_data_source.generate_presigned_url(
        ClientMethod="get_object",
        ExpiresIn=-1
    )

@pytest.mark.asyncio
async def test_generate_presigned_url_none_response_handling(s3_data_source, monkeypatch):
    """Test handling of None response from S3 client."""
    async def mock_generate_presigned_url(**kwargs):
        return None
    # Patch the S3 client's generate_presigned_url to return None
    monkeypatch.setattr(MockS3Client, "generate_presigned_url", mock_generate_presigned_url)
    response = await s3_data_source.generate_presigned_url(ClientMethod="get_object")

@pytest.mark.asyncio
async def test_generate_presigned_url_concurrent_execution(s3_data_source):
    """Test concurrent execution of multiple presigned URL generations."""
    # Run 10 concurrent requests
    tasks = [
        s3_data_source.generate_presigned_url(
            ClientMethod="get_object",
            Params={"Bucket": f"bucket{i}", "Key": f"key{i}"},
            ExpiresIn=3600 + i
        )
        for i in range(10)
    ]
    results = await asyncio.gather(*tasks)
    for res in results:
        pass

# 3. Large Scale Test Cases

@pytest.mark.asyncio
async def test_generate_presigned_url_large_scale_many_concurrent(s3_data_source):
    """Test large scale concurrent execution with 100 requests."""
    tasks = [
        s3_data_source.generate_presigned_url(
            ClientMethod="get_object",
            Params={"Bucket": f"bucket{i}", "Key": f"key{i}", "large_test": True},
            ExpiresIn=3600
        )
        for i in range(100)
    ]
    results = await asyncio.gather(*tasks)
    for res in results:
        pass

@pytest.mark.asyncio
async def test_generate_presigned_url_large_scale_mixed_success_and_error(s3_data_source):
    """Test large scale concurrent execution with mixed success and error."""
    tasks = []
    for i in range(50):
        # Success
        tasks.append(s3_data_source.generate_presigned_url(
            ClientMethod="get_object",
            Params={"Bucket": f"bucket{i}", "Key": f"key{i}"}
        ))
        # Error
        tasks.append(s3_data_source.generate_presigned_url(
            ClientMethod="invalid_method"
        ))
    results = await asyncio.gather(*tasks)
    success_count = sum(1 for r in results if r.success)
    error_count = sum(1 for r in results if not r.success)
    for r in results:
        if r.success:
            pass
        else:
            pass

# 4. Throughput Test Cases

@pytest.mark.asyncio
async def test_generate_presigned_url_throughput_small_load(s3_data_source):
    """Throughput test: small load (10 requests)."""
    tasks = [
        s3_data_source.generate_presigned_url(ClientMethod="get_object", Params={"Bucket": "b", "Key": str(i)})
        for i in range(10)
    ]
    results = await asyncio.gather(*tasks)
    for res in results:
        pass

@pytest.mark.asyncio
async def test_generate_presigned_url_throughput_medium_load(s3_data_source):
    """Throughput test: medium load (100 requests)."""
    tasks = [
        s3_data_source.generate_presigned_url(ClientMethod="get_object", Params={"Bucket": "b", "Key": str(i)})
        for i in range(100)
    ]
    results = await asyncio.gather(*tasks)
    for res in results:
        pass

@pytest.mark.asyncio
async def test_generate_presigned_url_throughput_high_volume(s3_data_source):
    """Throughput test: high volume (250 requests)."""
    tasks = [
        s3_data_source.generate_presigned_url(ClientMethod="get_object", Params={"Bucket": "b", "Key": str(i)})
        for i in range(250)
    ]
    results = await asyncio.gather(*tasks)
    # Validate all responses are successful and URLs are correct
    for res in results:
        pass

@pytest.mark.asyncio
async def test_generate_presigned_url_throughput_mixed_load(s3_data_source):
    """Throughput test: mixed load of success and error (100 requests)."""
    tasks = [
        s3_data_source.generate_presigned_url(ClientMethod="get_object", Params={"Bucket": "b", "Key": str(i)})
        if i % 2 == 0 else
        s3_data_source.generate_presigned_url(ClientMethod="invalid_method")
        for i in range(100)
    ]
    results = await asyncio.gather(*tasks)
    for i, res in enumerate(results):
        if i % 2 == 0:
            pass
        else:
            pass
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
import asyncio  # used to run async functions
from typing import Any, Dict, Optional

import pytest  # used for our unit tests
from app.sources.external.s3.s3 import S3DataSource


class ClientError(Exception):
    """Mock ClientError exception."""
    def __init__(self, response):
        self.response = response

# --- Mock aioboto3 session and client for async context manager ---

class MockS3Client:
    """Mock S3 client with async generate_presigned_url method."""
    async def generate_presigned_url(self, **kwargs):
        # Simulate correct URL generation based on input
        # For testing, return a dict with the input for validation
        if kwargs.get('ClientMethod') == 'bad_method':
            # Simulate botocore ClientError
            raise ClientError({
                'Error': {
                    'Code': 'InvalidClientMethod',
                    'Message': 'The client method is invalid.'
                }
            })
        # Simulate an edge case: Params missing required keys
        if kwargs.get('Params') == {'invalid': True}:
            raise ClientError({
                'Error': {
                    'Code': 'InvalidParams',
                    'Message': 'Params are invalid.'
                }
            })
        # Simulate normal response: return a presigned URL string
        url = f"https://mock-s3/{kwargs.get('ClientMethod')}"
        if 'Params' in kwargs:
            url += f"?params={kwargs['Params']}"
        if 'ExpiresIn' in kwargs:
            url += f"&expires={kwargs['ExpiresIn']}"
        if 'HttpMethod' in kwargs:
            url += f"&http={kwargs['HttpMethod']}"
        return url

    async def __aenter__(self):
        return self

    async def __aexit__(self, exc_type, exc, tb):
        pass

class MockSession:
    """Mock aioboto3 Session."""
    def client(self, service_name):
        return MockS3Client()

class S3Client:
    """Mock S3Client for dependency injection."""
    def get_session(self):
        return MockSession()

# --- Unit Tests for generate_presigned_url ---

@pytest.mark.asyncio
async def test_generate_presigned_url_basic_success():
    """Basic test: valid ClientMethod, no optional params, should succeed."""
    s3ds = S3DataSource(S3Client())
    resp = await s3ds.generate_presigned_url(ClientMethod='get_object')

@pytest.mark.asyncio
async def test_generate_presigned_url_with_all_params():
    """Basic test: all parameters provided, should succeed."""
    s3ds = S3DataSource(S3Client())
    params = {'Bucket': 'mybucket', 'Key': 'mykey'}
    resp = await s3ds.generate_presigned_url(
        ClientMethod='put_object',
        Params=params,
        ExpiresIn=1234,
        HttpMethod='PUT'
    )

@pytest.mark.asyncio
async def test_generate_presigned_url_params_none():
    """Edge case: Params explicitly None, should succeed."""
    s3ds = S3DataSource(S3Client())
    resp = await s3ds.generate_presigned_url(ClientMethod='get_object', Params=None)

@pytest.mark.asyncio
async def test_generate_presigned_url_invalid_client_method():
    """Edge case: Invalid ClientMethod triggers ClientError."""
    s3ds = S3DataSource(S3Client())
    resp = await s3ds.generate_presigned_url(ClientMethod='bad_method')

@pytest.mark.asyncio
async def test_generate_presigned_url_invalid_params():
    """Edge case: Invalid Params triggers ClientError."""
    s3ds = S3DataSource(S3Client())
    resp = await s3ds.generate_presigned_url(ClientMethod='get_object', Params={'invalid': True})

@pytest.mark.asyncio
async def test_generate_presigned_url_none_response_handling():
    """Edge case: _handle_s3_response with None returns error."""
    s3ds = S3DataSource(S3Client())
    # Directly test _handle_s3_response for None
    resp = s3ds._handle_s3_response(None)

@pytest.mark.asyncio
async def test_generate_presigned_url_dict_error_response_handling():
    """Edge case: _handle_s3_response with dict containing Error."""
    s3ds = S3DataSource(S3Client())
    error_dict = {'Error': {'Code': 'TestError', 'Message': 'Testing'}}
    resp = s3ds._handle_s3_response(error_dict)

@pytest.mark.asyncio
async def test_generate_presigned_url_concurrent_execution():
    """Test concurrent execution with asyncio.gather()."""
    s3ds = S3DataSource(S3Client())
    # Run several concurrent requests with different ClientMethods
    methods = ['get_object', 'put_object', 'delete_object']
    coros = [s3ds.generate_presigned_url(ClientMethod=m) for m in methods]
    results = await asyncio.gather(*coros)
    for resp, method in zip(results, methods):
        pass

@pytest.mark.asyncio
async def test_generate_presigned_url_concurrent_errors():
    """Test concurrent execution with some errors."""
    s3ds = S3DataSource(S3Client())
    coros = [
        s3ds.generate_presigned_url(ClientMethod='get_object'),
        s3ds.generate_presigned_url(ClientMethod='bad_method'),
        s3ds.generate_presigned_url(ClientMethod='get_object', Params={'invalid': True}),
    ]
    results = await asyncio.gather(*coros)

@pytest.mark.asyncio
async def test_generate_presigned_url_large_scale_concurrent():
    """Large scale test: 50 concurrent requests."""
    s3ds = S3DataSource(S3Client())
    coros = [
        s3ds.generate_presigned_url(ClientMethod='get_object', Params={'Bucket': f'b{i}', 'Key': f'k{i}'})
        for i in range(50)
    ]
    results = await asyncio.gather(*coros)
    for i, resp in enumerate(results):
        pass

@pytest.mark.asyncio
async def test_generate_presigned_url_large_scale_mixed():
    """Large scale test: 30 success, 20 error requests concurrently."""
    s3ds = S3DataSource(S3Client())
    coros = []
    # 30 valid
    for i in range(30):
        coros.append(s3ds.generate_presigned_url(ClientMethod='get_object', Params={'Bucket': f'b{i}', 'Key': f'k{i}'}))
    # 20 invalid
    for i in range(20):
        coros.append(s3ds.generate_presigned_url(ClientMethod='bad_method'))
    results = await asyncio.gather(*coros)
    for i in range(30):
        pass
    for i in range(30, 50):
        pass

@pytest.mark.asyncio
async def test_generate_presigned_url_throughput_small_load():
    """Throughput test: small load (10 requests)."""
    s3ds = S3DataSource(S3Client())
    coros = [s3ds.generate_presigned_url(ClientMethod='get_object', Params={'Bucket': 'b', 'Key': str(i)}) for i in range(10)]
    results = await asyncio.gather(*coros)

@pytest.mark.asyncio
async def test_generate_presigned_url_throughput_medium_load():
    """Throughput test: medium load (100 requests)."""
    s3ds = S3DataSource(S3Client())
    coros = [s3ds.generate_presigned_url(ClientMethod='get_object', Params={'Bucket': 'b', 'Key': str(i)}) for i in range(100)]
    results = await asyncio.gather(*coros)

@pytest.mark.asyncio
async def test_generate_presigned_url_throughput_high_volume():
    """Throughput test: high volume (200 requests)."""
    s3ds = S3DataSource(S3Client())
    coros = [s3ds.generate_presigned_url(ClientMethod='get_object', Params={'Bucket': 'b', 'Key': str(i)}) for i in range(200)]
    results = await asyncio.gather(*coros)
# codeflash_output is used to check that the output of the original code is the same as that of the optimized code.
#------------------------------------------------
from app.sources.external.s3.s3 import S3DataSource

To edit these changes git checkout codeflash/optimize-S3DataSource.generate_presigned_url-mhcyx9gg and push.