server: tests: add health check and concurrent request example

examples/server/tests/features/server.feature

@@ -1,5 +1,13 @@
 Feature: llama.cpp server
 
+  Background: The server is started and ready to accept prompts
+    When wait for the server to be started
+    Then wait for the server to be healthy
+
+  Scenario: Health endpoint
+    Given an health liveness probe
+    Then the server must be healthy
+
   Scenario Outline: run a completion request
     Given a prompt <prompt>
     When we request a completion
@@ -18,6 +26,14 @@ Feature: llama.cpp server
     Then the oai response contains completion tokens
 
     Examples: Prompts
-      | model          | system_prompt                | user_prompt                            |
-      | tinyllama-2    | You are ChatGPT.             | Say hello                              |
-      | tinyllama-2    | You are a coding assistant.  | Write the fibonacci function in c++    |
+      | model       | system_prompt               | user_prompt                         |
+      | tinyllama-2 | You are ChatGPT.            | Say hello                           |
+      | tinyllama-2 | You are a coding assistant. | Write the fibonacci function in c++ |
+
+
+  Scenario: Health endpoint during processing with concurrent requests
+    Given 2 slow concurrent prompts
+    Then wait for all slots processing
+    Then the server is overloaded
+    When wait for all slots idle
+    Then all prompts must be predicted

examples/server/tests/features/steps/steps.py

@@ -1,19 +1,77 @@
+import socket
+import threading
+import time
+from contextlib import closing
+
 import openai
 import requests
-from behave import *
+from behave import step
+from behave.api.async_step import async_run_until_complete
+
+base_fqdn = 'localhost'
+base_port = 8080
+base_url = f"http://{base_fqdn}:{base_port}"
 
 openai.api_key = 'llama.cpp'
-openai.api_base = "http://localhost:8080/v1/chat"
+openai.api_base = f"{base_url}/v1/chat"
+
+slow_prompt = 'say hello ' * 10
+fast_prompt = 'Write a joke'
+
+n_slots = 2
 
 
-@given(u'a prompt {prompt}')
+@step(u'wait for the server to be started')
+def step_wait_for_the_server_to_be_started(context):
+    server_started = False
+    while not server_started:
+        with closing(socket.socket(socket.AF_INET, socket.SOCK_STREAM)) as sock:
+            result = sock.connect_ex((base_fqdn, base_port))
+            if result != 0:
+                print("server not ready: ", base_fqdn, base_port, result)
+                time.sleep(1)
+            else:
+                return 0
+
+
+@step(u'wait for the server to be healthy')
+def step_wait_for_the_server_to_be_healthy(context):
+    status_code = 500
+    while status_code != 200:
+        status_code = requests.get(f'{base_url}/health').status_code
+        if status_code != 200:
+            time.sleep(1)
+
+
+@step(u'an health liveness probe')
+def step_an_health_liveness_probe(context):
+    response = requests.get(f'{base_url}/health')
+    context.status_code = response.status_code
+    context.response_data = response.json()
+
+
+@step(u'the server must be healthy')
+def step_server_healthy(context):
+    assert context.status_code == 200
+    assert context.response_data['status'] == 'ok'
+
+
+@step(u'the server is overloaded')
+@async_run_until_complete()
+async def step_server_overloaded(context):
+    response = requests.get(f'{base_url}/health?fail_on_no_slot')
+    assert response.status_code == 503
+    assert response.json()['status'] == 'no slot available'
+
+
+@step(u'a prompt {prompt}')
 def step_prompt(context, prompt):
     context.prompt = prompt
 
 
-@when(u'we request a completion')
+@step(u'we request a completion')
 def step_request_completion(context):
-    response = requests.post('http://localhost:8080/completion', json={
+    response = requests.post(f'{base_url}/completion', json={
         "prompt": context.prompt
     })
     status_code = response.status_code
@@ -21,28 +79,27 @@ def step_request_completion(context):
     context.response_data = response.json()
 
 
-@then(u'tokens are predicted')
+@step(u'tokens are predicted')
 def step_request_completion(context):
-    assert len(context.response_data['content']) > 0
-    assert context.response_data['timings']['predicted_n'] > 0
+    prompt_predicted(context.response_data)
 
 
-@given(u'a user prompt {user_prompt}')
+@step(u'a user prompt {user_prompt}')
 def step_user_prompt(context, user_prompt):
     context.user_prompt = user_prompt
 
 
-@given(u'a system prompt {system_prompt}')
+@step(u'a system prompt {system_prompt}')
 def step_system_prompt(context, system_prompt):
     context.system_prompt = system_prompt
 
 
-@given(u'a model {model}')
+@step(u'a model {model}')
 def step_model(context, model):
     context.model = model
 
 
-@when(u'we request the oai completions endpoint')
+@step(u'we request the oai completions endpoint')
 def step_oai_completions(context):
     context.chat_completion = openai.Completion.create(
         messages=[
@@ -59,8 +116,67 @@ def step_oai_completions(context):
     )
 
 
-@then(u'the oai response contains completion tokens')
+@step(u'the oai response contains completion tokens')
 def step_oai_response_has_completion_tokens(context):
     assert len(context.chat_completion.choices) == 1
     assert len(context.chat_completion.choices[0].message) > 0
     assert context.chat_completion.usage.completion_tokens > 0
+
+
+def async_prompt(context, prompt):
+    response = requests.post(f'{base_url}/completion', json={
+        "prompt": prompt
+    })
+
+    context.async_responses.append(response)
+
+
+@step(u'{n_prompt} {prompt_type} concurrent prompts')
+def step_n_concurrent_prompts(context, n_prompt, prompt_type):
+    prompt = fast_prompt
+    if prompt_type == 'slow':
+        prompt = slow_prompt
+    context.async_responses = []
+    context.threads = []
+    for i in range(int(n_prompt)):
+        thread = threading.Thread(target=async_prompt, args=(context, prompt))
+        thread.start()
+        context.threads.append(thread)
+
+
+def wait_for_slots_processing(context, expected_slots_processing):
+    while True:
+        health = requests.get(f'{base_url}/health').json()
+        if 'slots_processing' in health:  # FIXME when #5594 is merged
+            slots_processing = health['slots_processing']
+        else:
+            slots_processing = 0
+        if slots_processing == expected_slots_processing:
+            break
+        else:
+            time.sleep(0.2)
+
+
+@step(u'wait for all slots processing')
+def step_wait_for_all_slots_processing(context):
+    wait_for_slots_processing(context, n_slots)
+
+
+@step(u'wait for all slots idle')
+def step_wait_for_all_slots_idle(context):
+    wait_for_slots_processing(context, 0)
+
+
+@step(u'all prompts must be predicted')
+def step_all_prompts_must_be_predicted(context):
+    for thread in context.threads:
+        thread.join()
+    for async_response in context.async_responses:
+        assert async_response.status_code == 200
+        response_data = async_response.json()
+        prompt_predicted(response_data)
+
+
+def prompt_predicted(response_data):
+    assert len(response_data['content']) > 0
+    assert response_data['timings']['predicted_n'] > 0

examples/server/tests/tests.sh

@@ -6,6 +6,7 @@ then
     exit 1
 fi
 
+# kill the server at the end
 cleanup() {
     pkill -P $$
 }
@@ -20,9 +21,9 @@ set -eu
 ../../../build/bin/server \
             --model "$model_path" \
             --alias tinyllama-2 \
-            --ctx-size 64 \
+            --ctx-size 1024 \
             --parallel 2 \
-            --n-predict 32 \
+            --n-predict 1024 \
             --batch-size 32 \
             --threads 4 \
             --threads-batch 4 \
@@ -30,16 +31,5 @@ set -eu
             --cont-batching \
             "$@" &
 
-# Wait for the server to start
-max_attempts=30
-attempts=${max_attempts}
-until curl --silent --fail "http://localhost:8080/health" | jq -r '.status' | grep ok; do
-  attempts=$(( attempts - 1));
-  [ "${attempts}" -eq 0 ] && { echo "Server did not startup" >&2; exit 1; }
-  sleep_time=$(( (max_attempts - attempts) * 2 ))
-  echo "waiting for server to be ready ${sleep_time}s..."
-  sleep ${sleep_time}
-done
-
 # Start tests
 behave