server: logs - unified format and --log-format option (#5700)

* server: logs - always use JSON logger, add add thread_id in message, log task_id and slot_id

* server : skip GH copilot requests from logging

* server : change message format of server_log()

* server : no need to repeat log in comment

* server : log style consistency

* server : fix compile warning

* server : fix tests regex patterns on M2 Ultra

* server: logs: PR feedback on log level

* server: logs: allow to choose log format in json or plain text

* server: tests: output server logs in text

* server: logs switch init logs to server logs macro

* server: logs ensure value json value does not raised error

* server: logs reduce level VERBOSE to VERB to max 4 chars

* server: logs lower case as other log messages

* server: logs avoid static in general

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

* server: logs PR feedback: change text log format to: LEVEL [function_name] message | additional=data

---------

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

examples/server/tests/README.md

@@ -32,6 +32,7 @@ It's possible to override some scenario steps values with environment variables:
  - `PORT` -> `context.server_port` to set the listening port of the server during scenario, default: `8080`
  - `LLAMA_SERVER_BIN_PATH` -> to change the server binary path, default: `../../../build/bin/server`
  - `DEBUG` -> "ON" to enable steps and server verbose mode `--verbose`
+ - `SERVER_LOG_FORMAT_JSON` -> if set switch server logs to json format
 
 ### Run @bug, @wip or @wrong_usage annotated scenario
 

examples/server/tests/features/server.feature

@@ -29,9 +29,9 @@ Feature: llama.cpp server
     And   prometheus metrics are exposed
 
     Examples: Prompts
-      | prompt                           | n_predict | re_content                   | n_predicted |
-      | I believe the meaning of life is | 8         | read                         | 8           |
-      | Write a joke about AI            | 64        | (park<or>friends<or>scared)+ | 32          |
+      | prompt                           | n_predict | re_content                             | n_predicted |
+      | I believe the meaning of life is | 8         | (read<or>going)+                       | 8           |
+      | Write a joke about AI            | 64        | (park<or>friends<or>scared<or>always)+ | 32          |
 
   Scenario Outline: OAI Compatibility
     Given a model <model>

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

@@ -792,6 +792,8 @@ def start_server_background(context):
         server_args.extend(['--api-key', context.server_api_key])
     if context.debug:
         server_args.append('--verbose')
+    if 'SERVER_LOG_FORMAT_JSON' not in os.environ:
+        server_args.extend(['--log-format', "text"])
     print(f"starting server with: {context.server_path}", *server_args)
     context.server_process = subprocess.Popen(
         [str(arg) for arg in [context.server_path, *server_args]],