Observability & SRE
Structured logging, metrics, tracing, health checks, and SLO-friendly instrumentation.
How to Mock Database Query Duration in Python
Simulate realistic database query durations with random jitter for testing dashboards, alerts, and SLO calculations.
import random
import time
def mock_query_duration(db_name, avg_ms, jitter_ms=5, runs=3):
"""Simulate database query durations with realistic variation."""
durations = []
for _ in range(runs):
# Base duration plus random jitter (can be negative)
duration = avg_ms + random.uniform(-jitter_m…
How to Route Alerts by Severity in Python
Map alert severity levels to routing targets and simulate dispatching alerts to on-call pages, email, Slack, or logs.
def main():
# Severity levels with corresponding alert routing targets
routing_map = {
"critical": "call_page",
"high": "call_page",
"medium": "email_team",
"low": "slack_channel",
"info": "log_only"
}
# Simulated alerts with severity
alerts = [
{"na…
How to mock Prometheus alert rule thresholds in Python
Simulate a Prometheus alert rule with a configurable threshold and duration window, firing only when the metric exceeds the threshold long enough.
import time
import random
class MetricsStore:
def __init__(self):
self.metrics = {}
def set_metric(self, name, value, labels=None):
key = (name, tuple(sorted((labels or {}).items())))
self.metrics[key] = value
def get_metric(self, name, labels=None):
key = (name, tuple(s…
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Observability & SRE — Python code examples
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