当前位置：首页 > news >正文

vllm -- 源码学习1(寻找源码入口) (小白级教程)

news 2026/5/25 5:59:16

vllm服务的启动命令，通过启动命令去寻找源代码的入口。

source .venv/bin/activate vllm serve facebook/opt-125m --dtype=bfloat16

来看第一条命令source .venv/bin/activate(注: 一定要替换成自己的目录哟)。

这条命令用于激活本地用uv创建的虚拟环境。

因为vllm是通过uv进行安装的，所以要激活虚拟环境，才能直接使用vllm命令。

看下activate的源码。

if ! [ -z "${SCRIPT_PATH+_}" ] ; then _OLD_SCRIPT_PATH="$SCRIPT_PATH" fi # Get script path (only used if environment is relocatable). if [ -n "${BASH_VERSION:+x}" ] ; then SCRIPT_PATH="${BASH_SOURCE[0]}" if [ "$SCRIPT_PATH" = "$0" ]; then # Only bash has a reasonably robust check for source'dness. echo "You must source this script: \$ source $0" >&2 exit 33 fi elif [ -n "${ZSH_VERSION:+x}" ] ; then SCRIPT_PATH="${(%):-%x}" elif [ -n "${KSH_VERSION:+x}" ] ; then SCRIPT_PATH="${.sh.file}" fi deactivate () { unset -f pydoc >/dev/null 2>&1 || true # reset old environment variables # ! [ -z ${VAR+_} ] returns true if VAR is declared at all if ! [ -z "${_OLD_VIRTUAL_PATH:+_}" ] ; then PATH="$_OLD_VIRTUAL_PATH" export PATH unset _OLD_VIRTUAL_PATH fi if ! [ -z "${_OLD_VIRTUAL_PYTHONHOME+_}" ] ; then PYTHONHOME="$_OLD_VIRTUAL_PYTHONHOME" export PYTHONHOME unset _OLD_VIRTUAL_PYTHONHOME fi # The hash command must be called to get it to forget past # commands. Without forgetting past commands the $PATH changes # we made may not be respected hash -r 2>/dev/null if ! [ -z "${_OLD_VIRTUAL_PS1+_}" ] ; then PS1="$_OLD_VIRTUAL_PS1" export PS1 unset _OLD_VIRTUAL_PS1 fi unset VIRTUAL_ENV unset VIRTUAL_ENV_PROMPT if [ ! "${1-}" = "nondestructive" ] ; then # Self destruct! unset -f deactivate fi } # unset irrelevant variables deactivate nondestructive VIRTUAL_ENV='/home/src/.venv' if ([ "$OSTYPE" = "cygwin" ] || [ "$OSTYPE" = "msys" ]) && $(command -v cygpath &> /dev/null) ; then VIRTUAL_ENV=$(cygpath -u "$VIRTUAL_ENV") fi export VIRTUAL_ENV # Unset the `SCRIPT_PATH` variable, now that the `VIRTUAL_ENV` variable # has been set. This is important for relocatable environments. if ! [ -z "${_OLD_SCRIPT_PATH+_}" ] ; then SCRIPT_PATH="$_OLD_SCRIPT_PATH" export SCRIPT_PATH unset _OLD_SCRIPT_PATH else unset SCRIPT_PATH fi _OLD_VIRTUAL_PATH="$PATH" PATH="$VIRTUAL_ENV/bin:$PATH" export PATH if [ "xsrc" != x ] ; then VIRTUAL_ENV_PROMPT="src" else VIRTUAL_ENV_PROMPT=$(basename "$VIRTUAL_ENV") fi export VIRTUAL_ENV_PROMPT # unset PYTHONHOME if set if ! [ -z "${PYTHONHOME+_}" ] ; then _OLD_VIRTUAL_PYTHONHOME="$PYTHONHOME" unset PYTHONHOME fi if [ -z "${VIRTUAL_ENV_DISABLE_PROMPT-}" ] ; then _OLD_VIRTUAL_PS1="${PS1-}" PS1="(${VIRTUAL_ENV_PROMPT}) ${PS1-}" export PS1 fi # Make sure to unalias pydoc if it's already there alias pydoc 2>/dev/null >/dev/null && unalias pydoc || true pydoc () { python -m pydoc "$@" } # The hash command must be called to get it to forget past # commands. Without forgetting past commands the $PATH changes # we made may not be respected hash -r 2>/dev/null || true

看起来这个文件很多很复杂，如果简单理解，这个文件的核心目的就是修改PATH环境变量。

把虚拟环境的系统目录放到PATH的最前面。

所以在你激活虚拟环境后，执行python、vllm这些命令时，系统会先从.venv/bin/目录下查找这些命令。

理解了第一个命令，再来看第二个命令vllm serve facebook/opt-125m --dtype=bfloat16。

自然而然就知道这个命令存放在.venv/bin/目录下。

也可以用which命令验证下，如下图。

来看下vllm文件中写了什么

#!/home/src/.venv/bin/python3 # -*- coding: utf-8 -*- import sys from vllm.entrypoints.cli.main import main if __name__ == "__main__": if sys.argv[0].endswith("-script.pyw"): sys.argv[0] = sys.argv[0][:-11] elif sys.argv[0].endswith(".exe"): sys.argv[0] = sys.argv[0][:-4] sys.exit(main())

逐行解释代码的含义。

import sys

导入 Python 系统模块，用来获取命令行参数、退出程序等。

from vllm.entrypoints.cli.main import main

从 vLLM 源码里，导入真正的主函数 main ()，对应的源码vllm/entrypoints/cli/main.py。

if __name__ == "__main__":

用于判断是否直接运行了这段代码，如果别人import导入则不会执行后续逻辑。

if sys.argv[0].endswith("-script.pyw"):
sys.argv[0] = sys.argv[0][:-11]

elif sys.argv[0].endswith(".exe"):
sys.argv[0] = sys.argv[0][:-4]

对字符串进行截取

sys.exit(main())

最后一句，真正开始调用vllm的源码。