Temporal Code

Time-Native Programming for Python

Temporal Code introduces a programming paradigm where function behavior evolves over time. Instead of deploying new code and flipping a switch, you define multiple variants of a function and let a strategy decide which one runs — gradually shifting traffic, running canary tests, A/B comparisons, or switching at a scheduled time.

Zero external dependencies. Pure Python 3.10+.

Features

• @evolving decorator — Make any function time-aware with a single line
• Variant registration — Add new implementations via @func.variant("v2")
• 4 built-in rollout strategies:
  • GradualStrategy — Linear traffic shift over N days
  • CanaryStrategy — Small % traffic with auto-promote/rollback
  • ABTestStrategy — Even split with comparison reporting
  • ScheduledStrategy — Hard switch at a specific timestamp
• Automatic fallback — If the new variant throws, falls back to v1
• Performance tracking — Latency, success rate, call count per variant
• EvolutionTracker — Persistent JSON Lines log of all evolution events
• CLI tool (tc) — Inspect evolution history from the terminal

Installation

pip install temporal-code

Quick Start

from temporal_code import evolving

@evolving(start="2026-06-01", duration_days=14)
def rank_results(items):
    """v1: Simple sort."""
    return sorted(items)

@rank_results.variant("v2")
def rank_results_v2(items):
    """v2: ML-powered ranking (gradually takes over in 14 days)."""
    return ml_sort(items)

# Just call it — the strategy picks the variant automatically
results = rank_results(["banana", "apple", "cherry"])

During the 14-day window starting June 1st, traffic gradually shifts from v1 to v2. If v2 raises an exception, v1 handles the request as a fallback.

Strategies

GradualStrategy

Linearly shifts traffic from the old variant to the new one over a configurable duration.

from temporal_code import evolving, GradualStrategy

@evolving(strategy=GradualStrategy(start="2026-06-01", duration_days=7))
def my_func(x):
    return old_logic(x)

@my_func.variant("v2")
def my_func_v2(x):
    return new_logic(x)

CanaryStrategy

Routes a small fixed percentage of traffic to the new variant. Automatically promotes after N successful calls, or rolls back if the success rate drops below a threshold.

from temporal_code import evolving, CanaryStrategy

strategy = CanaryStrategy(
    canary_weight=0.1,         # 10% traffic to new variant
    promote_after=100,         # Decide after 100 calls
    rollback_threshold=0.95,   # Roll back if success < 95%
)

@evolving(strategy=strategy)
def process_payment(amount):
    return legacy_processor(amount)

@process_payment.variant("v2")
def process_payment_v2(amount):
    return new_processor(amount)

# After 100 calls to v2:
# - If success_rate >= 95%: auto-promote v2 to 100%
# - If success_rate < 95%: auto-rollback to v1

ABTestStrategy

Splits traffic evenly (or with custom weights) and collects comparison metrics. Does not auto-promote — you decide based on the report.

from temporal_code import evolving, ABTestStrategy

ab = ABTestStrategy(split=[0.5, 0.5])

@evolving(strategy=ab, name="greeting")
def greet(user):
    return f"Dear {user}, welcome."

@greet.variant("casual")
def greet_casual(user):
    return f"Hey {user}!"

# Run for a while, then check results:
report = ab.report(greet.variants)
# {'variants': [...], 'recommendation': "Recommend 'casual': 100.0% success, 0ms avg"}

ScheduledStrategy

Hard switch at a specific point in time. Before the timestamp, v1 runs; after it, v2 runs.

from temporal_code import scheduled

@scheduled(switch_at="2026-07-01")
def get_pricing(product):
    return {"model": "flat", "price": 99}

@get_pricing.variant("v2")
def get_pricing_v2(product):
    return {"model": "tiered", "base": 49, "premium": 149}

For multi-phase schedules, use the @temporal decorator:

from temporal_code import temporal

@temporal(schedule=[
    ("2026-06-01", "v1"),
    ("2026-07-01", "v2"),
    ("2026-09-01", "v3"),
])
def pricing(item):
    return item.base_price  # v1

EvolutionTracker

Track all evolution events (calls, promotions, rollbacks) to a persistent JSON Lines file:

from pathlib import Path
from temporal_code import EvolutionTracker
from temporal_code.decorators import set_tracker

# Enable persistent tracking
tracker = EvolutionTracker(Path("./evolution_logs"))
set_tracker(tracker)

# All @evolving functions now log to ./evolution_logs/evolution.jsonl
# Query history:
history = tracker.get_history(func_name="rank_results", event_type="call", limit=50)
summary = tracker.summary("rank_results")

Each log entry is a JSON object:

{"event": "call", "function": "rank_results", "variant": "v2", "success": true, "latency_ms": 1.23, "timestamp": "2026-06-05T10:30:00+00:00"}

API Reference

License

MIT