How to Generate a Mock Rollbar Error Report in Python

Create a realistic fake Rollbar error report with random timestamps, levels, messages, and counts for testing and demos.

Easy Python 3.8+ Aug 9, 2026 Modern tooling 13 views 0 copies

rollbar mock-data error-reporting testing

Python code

34 lines
Python 3.8+
Run it 
import json
import random
import time
from datetime import datetime, timedelta


def mock_rollbar_report(n_errors=5):
    messages = [
        "TypeError: unsupported operand type(s) for +: 'int' and 'str'",
        "KeyError: 'user_id'",
        "ValueError: invalid literal for int() with base 10: 'abc'",
        "AttributeError: 'NoneType' object has no attribute 'split'",
        "IndexError: list index out of range",
        "FileNotFoundError: [Errno 2] No such file or directory: 'data.csv'",
        "ZeroDivisionError: division by zero",
        "ImportError: No module named 'requests'",
    ]
    report = []
    now = datetime.utcnow()
    for i in range(n_errors):
        report.append({
            "timestamp": (now - timedelta(minutes=random.randint(0, 120))).isoformat() + "Z",
            "level": random.choice(["error", "critical", "warning"]),
            "message": random.choice(messages),
            "code": random.choice(["E001", "E002", "E003"]),
            "count": random.randint(1, 100),
            "environment": random.choice(["production", "staging", "development"]),
        })
    return report


if __name__ == "__main__":
    report = mock_rollbar_report(3)
    print(json.dumps(report, indent=2))

Output

stdout 
[
  {
    "timestamp": "2024-01-15T10:23:45.123456Z",
    "level": "error",
    "message": "KeyError: 'user_id'",
    "code": "E002",
    "count": 42,
    "environment": "production"
  },
  {
    "timestamp": "2024-01-15T09:15:30.654321Z",
    "level": "warning",
    "message": "FileNotFoundError: [Errno 2] No such file or directory: 'data.csv'",
    "code": "E001",
    "count": 7,
    "environment": "staging"
  },
  {
    "timestamp": "2024-01-15T08:30:10.987654Z",
    "level": "critical",
    "message": "ZeroDivisionError: division by zero",
    "code": "E003",
    "count": 89,
    "environment": "development"
  }
]

How it works

This function builds a list of dictionaries that mimic a Rollbar error report. It uses datetime.utcnow() as the reference point and subtracts random minutes to create realistic timestamps in ISO 8601 format with a 'Z' suffix for UTC. Random selection from predefined messages, levels, codes, counts, and environments adds variety while keeping the output plausible. The json.dumps call with indent=2 produces a readable, formatted JSON array that matches the structure of real Rollbar API responses.

Common mistakes

  • Forgetting the 'Z' suffix when generating ISO timestamps for UTC time
  • Using `random.choice` without importing `random` explicitly
  • Hardcoding timestamps instead of generating them relative to now

Variations

  1. Use `datetime.now(timezone.utc)` with `isoformat(timespec='milliseconds')` for higher precision
  2. Accept a `seed` parameter and call `random.seed(seed)` for reproducible outputs

Real-world use cases

  • Testing error-reporting dashboards without polluting production Rollbar with real errors.
  • Generating demo data for engineering blog posts or internal tooling walkthroughs.
  • Feeding mock error streams into alerting systems to verify notification pipelines and Slack integrations.

Sponsored

Run this sample

Open the browser IDE to tweak the example and see results without installing anything.

Open editor

More from Modern tooling

Keep learning

Related tutorials and quizzes for this topic.

Tutorials

Quizzes