IO同步

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">req_a</span><span class="hljs-params">()</span>:</span>
    <span class="hljs-string">"""模拟请求a"""</span>
    print(<span class="hljs-string">'开始处理请求req_a'</span>)
    print(<span class="hljs-string">'完成处理请求req_a'</span>)

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">req_b</span><span class="hljs-params">()</span>:</span>
    <span class="hljs-string">"""模拟请求b"""</span>
    print(<span class="hljs-string">'开始处理请求req_b'</span>)
    print(<span class="hljs-string">'完成处理请求req_b'</span>)

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">main</span><span class="hljs-params">()</span>:</span>
    <span class="hljs-string">"""模拟tornado框架，处理两个请求"""</span>
    req_a()
    req_b()

<span class="hljs-keyword">if</span> __name__ == <span class="hljs-string">"__main__"</span>:
    main()

开始处理请求req_a
完成处理请求req_a
开始处理请求req_b
完成处理请求req_b

<span class="hljs-keyword">import</span> time

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">long_io</span><span class="hljs-params">()</span>:</span>
    <span class="hljs-string">"""模拟耗时IO操作"""</span>
    print(<span class="hljs-string">"开始执行IO操作"</span>)
    time.sleep(<span class="hljs-number">5</span>)
    print(<span class="hljs-string">"完成IO操作"</span>)
    <span class="hljs-keyword">return</span> <span class="hljs-string">"io result"</span>

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">req_a</span><span class="hljs-params">()</span>:</span>
    print(<span class="hljs-string">"开始处理请求req_a"</span>)
    ret = long_io()
    print(<span class="hljs-string">"ret: %s"</span> % ret)
    print(<span class="hljs-string">"完成处理请求req_a"</span>)

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">req_b</span><span class="hljs-params">()</span>:</span>
    print(<span class="hljs-string">"开始处理请求req_b"</span>)
    print(<span class="hljs-string">"完成处理请求req_b"</span>)

<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">main</span><span class="hljs-params">()</span>:</span>
    req_a()
    req_b()

<span class="hljs-keyword">if</span> __name__==<span class="hljs-string">"__main__"</span>:
    main()

开始处理请求req_a
开始执行IO操作
完成IO操作
ret: io result
完成处理请求req_a
开始处理请求req_b
完成处理请求req_b

  说明：耗时的操作会将代码执行阻塞住，即req_a未处理完req_b是无法执行的