litellm/tests/local_testing/test_least_busy_routing.py
mateo-berri 48cc4efca3 fix(least-busy): share in-flight request counts across proxy workers
Least-busy kept one dict of in-flight counts per model group in the
router cache, which reads in-memory first, so every worker and replica
routed on its own stale copy and each write overwrote the shared value.

Counts now live in one key per deployment, incremented and read through
Redis when the router has a Redis cache, and in the process-local cache
otherwise.
2026-09-05 20:39:22 -07:00

278 lines
8.4 KiB
Python

#### What this tests ####
# This tests the router's ability to identify the least busy deployment
import asyncio
import random
import time
import traceback
from dotenv import load_dotenv
load_dotenv()
import pytest
import litellm
from litellm import Router
from litellm.caching.caching import DualCache
from litellm.router_strategy.least_busy import LeastBusyLoggingHandler
### UNIT TESTS FOR LEAST BUSY LOGGING ###
def test_model_added():
test_cache = DualCache()
least_busy_logger = LeastBusyLoggingHandler(router_cache=test_cache)
kwargs = {
"litellm_params": {
"metadata": {
"model_group": "gpt-3.5-turbo",
"deployment": "azure/gpt-4.1-mini",
},
"model_info": {"id": "1234"},
}
}
least_busy_logger.log_pre_api_call(model="test", messages=[], kwargs=kwargs)
request_count_api_key = "gpt-3.5-turbo_request_count:1234"
assert test_cache.get_cache(key=request_count_api_key) == 1
def test_get_available_deployments():
test_cache = DualCache()
least_busy_logger = LeastBusyLoggingHandler(router_cache=test_cache)
model_group = "gpt-3.5-turbo"
deployment = "azure/gpt-4.1-mini"
kwargs = {
"litellm_params": {
"metadata": {
"model_group": model_group,
"deployment": deployment,
},
"model_info": {"id": "1234"},
}
}
least_busy_logger.log_pre_api_call(model="test", messages=[], kwargs=kwargs)
request_count_api_key = f"{model_group}_request_count:1234"
assert test_cache.get_cache(key=request_count_api_key) == 1
# test_get_available_deployments()
@pytest.mark.parametrize("async_test", [True, False])
@pytest.mark.asyncio
async def test_router_get_available_deployments(async_test):
"""
Tests if 'get_available_deployments' returns the least busy deployment
"""
model_list = [
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 1440,
},
"model_info": {"id": 1},
},
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 6,
},
"model_info": {"id": 2},
},
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 6,
},
"model_info": {"id": 3},
},
]
router = Router(
model_list=model_list,
routing_strategy="least-busy",
set_verbose=False,
num_retries=3,
) # type: ignore
router.leastbusy_logger.test_flag = True
model_group = "azure-model"
request_count_dict = {"1": 10, "2": 54, "3": 100}
cache_keys = {
deployment_id: f"{model_group}_request_count:{deployment_id}"
for deployment_id in request_count_dict
}
if async_test is True:
for deployment_id, count in request_count_dict.items():
await router.cache.async_set_cache(key=cache_keys[deployment_id], value=count)
deployment = await router.async_get_available_deployment(
model=model_group, messages=None, request_kwargs={}
)
else:
for deployment_id, count in request_count_dict.items():
router.cache.set_cache(key=cache_keys[deployment_id], value=count)
deployment = router.get_available_deployment(model=model_group, messages=None)
print(f"deployment: {deployment}")
assert deployment["model_info"]["id"] == "1"
## run router completion - assert completion event, no change in 'busy'ness once calls are complete
router.completion(
model=model_group,
messages=[{"role": "user", "content": "Hey, how's it going?"}],
)
# wait 2 seconds
time.sleep(2)
return_dict = {
deployment_id: router.cache.get_cache(key=cache_key)
for deployment_id, cache_key in cache_keys.items()
}
assert router.leastbusy_logger.logged_success == 1
assert return_dict["1"] == 10
assert return_dict["2"] == 54
assert return_dict["3"] == 100
## Test with Real calls ##
@pytest.mark.asyncio
async def test_router_atext_completion_streaming():
prompt = "Hello, can you generate a 500 words poem?"
model = "azure-model"
model_list = [
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 1440,
},
"model_info": {"id": 1},
},
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 6,
},
"model_info": {"id": 2},
},
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 6,
},
"model_info": {"id": 3},
},
]
router = Router(
model_list=model_list,
routing_strategy="least-busy",
set_verbose=False,
num_retries=3,
) # type: ignore
### Call the async calls in sequence, so we start 1 call before going to the next.
## CALL 1
await asyncio.sleep(random.uniform(0, 2))
await router.atext_completion(model=model, prompt=prompt, stream=True)
## CALL 2
await asyncio.sleep(random.uniform(0, 2))
await router.atext_completion(model=model, prompt=prompt, stream=True)
## CALL 3
await asyncio.sleep(random.uniform(0, 2))
await router.atext_completion(model=model, prompt=prompt, stream=True)
## check if calls equally distributed
cache_dict = {
deployment_id: router.cache.get_cache(key=f"{model}_request_count:{deployment_id}")
for deployment_id in ("1", "2", "3")
}
for k, v in cache_dict.items():
assert v == 1, f"Failed. K={k} called v={v} times, cache_dict={cache_dict}"
# asyncio.run(test_router_atext_completion_streaming())
@pytest.mark.asyncio
async def test_router_completion_streaming():
litellm.set_verbose = True
messages = [
{"role": "user", "content": "Hello, can you generate a 500 words poem?"}
]
model = "azure-model"
model_list = [
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 1440,
},
"model_info": {"id": 1},
},
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 6,
},
"model_info": {"id": 2},
},
{
"model_name": "azure-model",
"litellm_params": {
"model": "openai/gpt-4.1-mini",
"api_key": "os.environ/OPENAI_API_KEY",
"rpm": 6,
},
"model_info": {"id": 3},
},
]
router = Router(
model_list=model_list,
routing_strategy="least-busy",
set_verbose=False,
num_retries=3,
) # type: ignore
### Call the async calls in sequence, so we start 1 call before going to the next.
## CALL 1
await asyncio.sleep(random.uniform(0, 2))
await router.acompletion(model=model, messages=messages, stream=True)
## CALL 2
await asyncio.sleep(random.uniform(0, 2))
await router.acompletion(model=model, messages=messages, stream=True)
## CALL 3
await asyncio.sleep(random.uniform(0, 2))
await router.acompletion(model=model, messages=messages, stream=True)
## check if calls equally distributed
cache_dict = {
deployment_id: router.cache.get_cache(key=f"{model}_request_count:{deployment_id}")
for deployment_id in ("1", "2", "3")
}
for k, v in cache_dict.items():
assert v == 1, f"Failed. K={k} called v={v} times, cache_dict={cache_dict}"