Retrying after connection broken by NewConnectionError

现象：

pip install boto3

报错：

(RunningFast) ➜  stable pip install boto3
Collecting boto3
  Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by ‘NewConnectionError(‘<pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f30c47e8710>: Failed to establish a new connection: [Errno -2] Name or service not known’,)’: /simple/boto3/
...
  Retrying (Retry(total=0, connect=None, read=None, redirect=None)) after connection broken by ‘NewConnectionError(‘<pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f30c306b5d0>: Failed to establish a new connection: [Errno -2] Name or service not known’,)’: /simple/boto3/
  Could not find a version that satisfies the requirement boto3 (from versions: )
No matching distribution found for boto3

Failed to establish a new connection Errno -2  Name or service not known

Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by ‘NewConnectionError(‘<pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7f30c47e8710>: Failed to establish a new connection: [Errno -2] Name or service not known’,)’: /simple/boto3/

原因：当时网络不稳定，连不上pip的源，导致报网络相关的错误

解决办法：

• 换个时间（网络就正常了）
  • 此处当时就是这么做的：换了个时间，第二天早上，网络正常了，再去pip install boto3，就可以了
• 给pip加上代理
  • 确保可以正常访问pip的源
    • 如何操作，详见前面章节：给pip加代理