Cloud + Python
Cloud SDK patterns — storage, serverless handlers, secrets, and deployment helpers.
Generate a Mock Presigned URL in Python with HMAC
Build a mock AWS S3 presigned URL using an HMAC-SHA256 signature, mimicking the core SigV4 pattern without cloud SDK dependencies.
import hashlib
import hmac
import time
import base64
def generate_presigned_url_mock(secret_key, bucket, object_key, expires_in=3600):
# Build the canonical request string (simplified AWS SigV4 style)
timestamp = str(int(time.time()))
expiry = str(int(time.time()) + expires_in)
payload = f"GET\n/{buck…How to Calculate Cloud Cost Estimates with a Python Dictionary
Mocks a cloud pricing calculator using a dictionary of service rates and computes total estimated cost for given service hours.
def estimate_cost(service, hours, rate_table=None):
if rate_table is None:
rate_table = {
"basic": 50,
"standard": 75,
"premium": 100
}
if service not in rate_table:
raise ValueError(f"Unknown service: {service}")
return rate_table[service] * hour…How to Calculate VPC Subnet CIDR Details in Python
Compute network address, broadcast address, address count, prefix length, and netmask for any IPv4 CIDR using the Python standard library's ipaddress module.
import ipaddress
def subnet_details(cidr: str) -> dict:
network = ipaddress.ip_network(cidr, strict=False)
return {
"network_address": str(network.network_address),
"broadcast_address": str(network.broadcast_address),
"num_addresses": network.num_addresses,
"prefix_length": ne…How to Check an SCP Deny List in Python
Load a JSON SCP policy file, extract the deny_list, and check if a target ARN is denied.
import json
from pathlib import Path
def evaluate_scp_deny_list(policy_path: Path, target_path: str) -> bool:
policy = json.loads(policy_path.read_text())
deny_list = policy.get("deny_list", [])
return target_path in deny_list
if __name__ == "__main__":
policy_file = Path("scp_policy.json")
pol…How to Enforce Tag Policies on AWS Resources in Python
Build a reusable Python class that checks AWS resources against a required-tag policy and reports compliance with missing tags.
import json
from dataclasses import dataclass, field
from typing import Dict, List
@dataclass
class Resource:
arn: str
tags: Dict[str, str] = field(default_factory=dict)
class TagPolicyEnforcer:
def __init__(self, required_tags: List[str]):
self.required_tags = set(required_tags)
def enfor…How to Evaluate IAM Policy Allow vs Deny in Python
Evaluate an AWS-style IAM policy dict with explicit deny overriding allow and default deny.
import json
def evaluate_policy(action, resource, policy):
"""Evaluate an IAM-like policy dict.
Explicit deny wins over allow. Default is deny.
"""
for statement in policy.get("Statement", []):
effect = statement.get("Effect")
actions = statement.get("Action", [])
resources = …How to Mock AWS Secrets Manager in Python
Create a lightweight mock of AWS Secrets Manager's get_secret_value API to test secret retrieval without cloud dependencies.
import json
from typing import Optional
class MockSecretsManager:
"""A simple mock of AWS Secrets Manager's get_secret_value API."""
def __init__(self):
self._secrets: dict[str, str] = {}
def create_secret(self, secret_id: str, secret_value: str) -> None:
"""Store a secret value under a…How to Mock Auto Scaling Policy Scale Out in Python
Define a mock auto-scaling function that scales out capacity by a factor up to a max, simulating AWS-like events.
def mock_scale_out(current_capacity: int, max_capacity: int, scale_factor: int = 1) -> tuple:
"""
Mock auto-scaling policy: scales out by the specified factor
if capacity allows, capped at max_capacity.
"""
if current_capacity >= max_capacity:
return current_capacity, False
new_cap…How to Mock Azure Service Bus Queue in Python
A lightweight in-memory mock of the Azure Service Bus queue API for local testing without cloud dependencies.
import json
import time
from collections import deque
class ServiceBusQueueMock:
def __init__(self, queue_name):
self.queue_name = queue_name
self._messages = deque()
self._dead_letter_queue = deque()
self._message_counter = 0
def send_message(self, body, message_id=None, prop…How to Mock CloudFront Invalidation Paths in Python
Build a sorted, deduplicated list of CloudFront invalidation paths from a set of file paths, adding implicit index.html entries.
import argparse
def build_invalidation_paths(files, include_index=True):
"""
Create CloudFront invalidation paths from a list of files.
Converts file names to root-relative paths and optionally adds /index.html.
"""
paths = []
for f in files:
f = f.strip()
if not f:
…How to Validate AWS Security Group Ingress Rules in Python
Validates AWS security group ingress rules (protocol, port ranges, CIDR, description) and returns a list of errors or OK.
from dataclasses import dataclass
from typing import List, Optional
@dataclass
class SecurityGroupRule:
protocol: str
port_range: tuple
cidr: str
description: str = ""
def validate_ingress_rule(rule: SecurityGroupRule) -> List[str]:
"""Validate a security group ingress rule against common AWS pat…How to plan reserved capacity from a CSV in Python
Read a CSV of workloads with csv.DictReader and compute a mock reserved capacity plan with headroom per service.
import csv
import io
def plan_reserved_capacity(workloads_csv: str) -> list[dict]:
"""Read a CSV of workloads and return a plan for reserved capacity per service."""
reader = csv.DictReader(io.StringIO(workloads_csv))
plan = []
for row in reader:
service = row["service"]
avg_load = fl…Mock S3, GCS, and Azure storage with a Python abstract interface
Define an abstract Storage interface and implement a local, filesystem-backed mock so S3, GCS, and Azure code can be tested without cloud dependencies.
from abc import ABC, abstractmethod
from pathlib import Path
class Storage(ABC):
@abstractmethod
def put(self, name: str, data: bytes) -> None:
pass
@abstractmethod
def get(self, name: str) -> bytes:
pass
class LocalStorage(Storage):
def __init__(self, base_dir: str = "mock_sto…Browse by section
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Cloud + Python — Python code examples
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