common : reimplement logging (#9418)

https://github.com/ggerganov/llama.cpp/pull/9418

examples/server/tests/.gitignore

@@ -0,0 +1 @@
+.venv

examples/server/tests/README.md

@@ -40,7 +40,6 @@ 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/llama-server`                         |
 | `DEBUG`                  | "ON" to enable steps and server verbose mode `--verbose`                                       |
-| `SERVER_LOG_FORMAT_JSON` | if set switch server logs to json format                                                       |
 | `N_GPU_LAYERS`           | number of model layers to offload to VRAM `-ngl --n-gpu-layers`                                |
 
 ### Run @bug, @wip or @wrong_usage annotated scenario

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

@@ -1372,8 +1372,6 @@ def start_server_background(context):
         server_args.append('--verbose')
     if context.lora_file:
         server_args.extend(['--lora', context.lora_file])
-    if 'SERVER_LOG_FORMAT_JSON' not in os.environ:
-        server_args.extend(['--log-format', "text"])
 
     args = [str(arg) for arg in [context.server_path, *server_args]]
     print(f"bench: starting server with: {' '.join(args)}")