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How to Mock a Kubeflow Pipeline in Python
Build a minimal in-memory mock of a Kubeflow pipeline DAG using dataclasses and OrderedDict to chain component functions.
from typing import Dict, Any
from dataclasses import dataclass, field
from collections import OrderedDict
@dataclass
class KubeflowPipelineMock:
"""A minimal mock of a Kubeflow pipeline DAG."""
name: str
components: OrderedDict[str, callable] = field(default_factory=OrderedDict)
def add_component(se…How to Stage ML Model Workflows with Python Classes
Defines a Stage class to model ML pipeline stages with variants and mocks, printing grammar for Model, Staging, and Production stages.
class Stage:
def __init__(self, name):
self.name = name
self.mocks = []
self.variants = []
def add_mock(self, mock_name):
self.mocks.append(mock_name)
def add_variant(self, variant_name, productions=()):
self.variants.append((variant_name, list(productions)))
…Mock a Flyte ML workflow in Python
Build a lightweight mock of a Flyte ML pipeline with dataclasses and a simple execution loop that passes outputs between tasks.
from dataclasses import dataclass, field
from typing import List, Dict, Optional
import time
@dataclass
class FlyteTask:
name: str
inputs: Dict = field(default_factory=dict)
outputs: Dict = field(default_factory=dict)
def run(self) -> Dict:
time.sleep(0.1) # simulate work
return sel…How to Mock Sequential Calls in Python with unittest.mock
Use Mock.side_effect to return a different result for each sequential call and verify the call order with assert_has_calls.
import unittest
from unittest.mock import Mock
class Service:
def fetch(self, item_id):
raise NotImplementedError
def process_items(service, ids):
results = []
for item_id in ids:
result = service.fetch(item_id)
results.append(result)
return results
if __name__ == "__main__":…Cross Shard Query Scatter Gather Mock in Python
Simulate a distributed database cross-shard query using a scatter-gather pattern with a mock Python implementation.
from dataclasses import dataclass
from typing import List, Dict
@dataclass
class NodeResponse:
node_id: int
data: Dict[str, float]
def mock_query_shard(shard_id: int, shard_data: Dict[str, float], query: str) -> NodeResponse:
"""Simulate querying a single shard, returning matches whose value > 50."""
…How to Replicate Data Across All Shards in Python
Mocks a global table that replicates a key-value pair to every shard, ensuring reads return the same value from any shard.
from dataclasses import dataclass
from typing import Dict, List
@dataclass
class Shard:
id: str
data: Dict[str, int]
class GlobalTable:
def __init__(self, shards: List[Shard]):
self._shards = {s.id: s for s in shards}
def set_value(self, key: str, value: int) -> None:
"""Replicate …How to Mock a Redis Session Store in Python
An in-memory RedisSessionStore class with TTL-based expiry, get/set/delete/exists methods, and JSON field support—perfect for testing and prototyping without a live Redis.
import time
import json
from collections import defaultdict
class RedisSessionStore:
"""In-memory mock of a Redis-backed session store."""
def __init__(self, ttl=3600):
self._data = defaultdict(dict)
self._expires = {}
self._ttl = ttl
def set(self, session_id, field, value):
…How to Build a GitOps Argo CD Sync Mock in Python
Simulate Argo CD-style GitOps deployment sync with Python dataclasses, random success rates, and force-sync retry logic.
import random
import time
from dataclasses import dataclass, field
from typing import List, Dict
@dataclass
class Application:
name: str
source_repo: str
target_revision: str
synced: bool = False
health_status: str = "Healthy"
history: List[Dict] = field(default_factory=list)
def sync(se…How to Mock Kubernetes Services with a ClusterIP Registry in Python
Simulate Kubernetes service discovery by assigning ClusterIP addresses to dataclass-defined services, with JSON export for inspection or testing.
import json
from dataclasses import dataclass, asdict
from typing import Dict, Optional
@dataclass
class Service:
name: str
namespace: str
cluster_ip: str
selector: Dict[str, str]
port: int
target_port: Optional[int] = None
class ClusterIPServiceRegistry:
_ip_counter = 0
def __init…How to Mock Multi-Stage Docker Builds in Python
Simulate a multi-stage Docker build in pure Python using classes and temp directories to understand how build stages copy artifacts into a final image.
# Simulate multi-stage Docker build with pure Python
from pathlib import Path
import tempfile
import shutil
class BuildContext:
"""Mimics a Docker build context with stages."""
def __init__(self, name):
self.name = name
self.files = {}
def add_file(self, dest, content):
s…How to Mock a CI Pipeline with Build, Test, and Deploy Stages in Python
Simulate a three-stage CI pipeline (build, test, deploy) in Python with random pass/fail logic, early exit on failure, and measured stage durations.
import time
import random
from dataclasses import dataclass
@dataclass
class StageResult:
name: str
status: str
duration: float
def run_stage(name: str, success_chance: float = 0.9) -> StageResult:
"""Simulate a pipeline stage with random success/failure."""
start = time.time()
time.sleep(r…How to Mock a Dockerfile Multi-Stage Build in Python
Simulate a Dockerfile multi-stage build process in Python using dataclasses to validate stage ordering and file availability before you write the real Dockerfile.
from dataclasses import dataclass
from pathlib import Path
@dataclass
class BuildStage:
name: str
base_image: str
files: list[str]
commands: list[str]
def run_build(stage: BuildStage, context_dir: Path):
print(f"=== Stage: {stage.name} (base: {stage.base_image}) ===")
for file in stage.file…How to Mock a Feature Flag Rollout Percentage in Python
Simulate a percentage-based feature flag rollout by hashing a user ID to deterministically enable features for a subset of users.
import random
from dataclasses import dataclass
@dataclass
class FeatureFlag:
name: str
rollout_percentage: int
def is_feature_enabled(feature_flag: FeatureFlag, user_id: str) -> bool:
hashed_id = hash(user_id) % 100
return hashed_id < feature_flag.rollout_percentage
if __name__ == "__main__":
…How to Mock a GitHub Actions Workflow in Python
Build a dataclass-based model of a GitHub Actions workflow and simulate its execution to validate steps and outputs before deployment.
import json
from dataclasses import dataclass, asdict
from typing import List, Dict, Any
@dataclass
class Step:
name: str
run: str
@dataclass
class Job:
name: str
steps: List[Step]
runs_on: str = "ubuntu-latest"
@dataclass
class Workflow:
name: str
jobs: List[Job]
def to_github_a…How to Replace Fields in an Immutable Dataclass in Python
Create a new copy of a frozen dataclass with selected fields changed, leaving the original unchanged.
from dataclasses import dataclass, replace
@dataclass(frozen=True)
class ServerConfig:
name: str
cpu: int = 2
ram: int = 4096
tags: tuple = ()
original = ServerConfig("web-01", cpu=4, tags=("env:prod",))
updated = replace(original, ram=8192, tags=("env:prod", "region:us-east"))
print("Original:", …Browse by section
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