title: WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available
body: <p>I would like to use Python3.8.x on Google Cloud Compute Engine.</p>
  <p>First, I created an instance with <code>gcloud</code> command.</p>
  <pre><code>gcloud compute instances create \
    pegasus-test \
    --zone=asia-northeast1-b \
    --machine-type=n1-highmem-8 \
    --boot-disk-size=500GB \
    --image-project=ml-images \
    --image-family=tf-1-15 \
    --maintenance-policy TERMINATE --restart-on-failure
  </code></pre>
  <p>In default, Python version is 3.5.3.</p>
  <pre><code>python3 -V
  Python 3.5.3
  </code></pre>
  <p>Therefore, I upgraded Python. I followed this instruction. (<a href="https://stackoverflow.com/questions/47273260/google-cloud-compute-engine-change-to-python-3-6">google cloud compute engine change to python 3.6</a>)</p>
  <pre><code>cd /tmp
  wget https://www.python.org/ftp/python/3.8.3/Python-3.8.3.tgz
  tar -xvf Python-3.8.3.tgz
  cd Python-3.8.3
  ./configure
  sudo apt-get install zlib1g-dev
  sudo make
  sudo make install
  </code></pre>
  <p>I got no error message.
  Now, I have Python3.8.3.</p>
  <pre><code>python3 -V
  Python 3.8.3
  </code></pre>
  <p>Next, I would like to use PEGASUS. (<a href="https://github.com/google-research/pegasus" rel="noreferrer">https://github.com/google-research/pegasus</a>)</p>
  <pre><code>git clone https://github.com/google-research/pegasus
  cd pegasus
  export PYTHONPATH=.
  pip3 install -r requirements.txt
  </code></pre>
  <p>Then, I got an error message.</p>
  <pre><code>WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
  Collecting absl-py (from -r requirements.txt (line 1))
    WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;
  Can't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/absl-py/
    WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;
  Can't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/absl-py/
    WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;
  Can't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/absl-py/
    WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;
  Can't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/absl-py/
    WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;
  Can't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/absl-py/
    Could not fetch URL https://pypi.org/simple/absl-py/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(
  host='pypi.org', port=443): Max retries exceeded with url: /simple/absl-py/ (Caused by SSLError(&quot;Can't connect to HTTPS URL beca
  use the SSL module is not available.&quot;)) - skipping
    ERROR: Could not find a version that satisfies the requirement absl-py (from -r requirements.txt (line 1)) (from versions: non
  e)
  ERROR: No matching distribution found for absl-py (from -r requirements.txt (line 1))
  WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
  Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='
  pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError(&quot;Can't connect to HTTPS URL because the SS
  L module is not available.&quot;)) - skipping
  </code></pre>
  <p>I checked pip's version.</p>
  <pre><code>pip3 -V
  pip 19.2.3 from /usr/local/lib/python3.8/site-packages/pip (python 3.8)
  </code></pre>
  <p>So, I tried to upgrade pip. <code>pip3 install --upgrade pip</code> Then, I got this error message.</p>
  <pre><code>WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
  WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;Ca
  n't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/pip/
  WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;Ca
  n't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/pip/
  WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;Ca
  n't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/pip/
  WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;Ca
  n't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/pip/
  WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(&quot;Ca
  n't connect to HTTPS URL because the SSL module is not available.&quot;)': /simple/pip/
  Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='
  pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError(&quot;Can't connect to HTTPS URL because the SS
  L module is not available.&quot;)) - skipping
  Requirement already up-to-date: pip in /usr/local/lib/python3.8/site-packages (19.2.3)
  WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
  Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='
  pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError(&quot;Can't connect to HTTPS URL because the SS
  L module is not available.&quot;)) - skipping
  </code></pre>
  <p>So, next I used <code>pip</code> instead of <code>pip3</code>. I input <code>pip install -r requirements.txt</code></p>
  <p>This is the result.</p>
  <pre><code>Defaulting to user installation because normal site-packages is not writeable
  Requirement already satisfied: absl-py in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 1)) (0.9.0)
  Requirement already satisfied: mock in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 2)) (3.0.5)
  Requirement already satisfied: numpy in /usr/local/lib/python2.7/dist-packages (from -r requirements.txt (line 3)) (1.16.6)
  Collecting rouge-score
    Downloading rouge_score-0.0.4-py2.py3-none-any.whl (22 kB)
  Collecting sacrebleu
    Downloading sacrebleu-1.3.7.tar.gz (26 kB)
      ERROR: Command errored out with exit status 1:
       command: /usr/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '&quot;'&quot;'/tmp/pip-install-HCHhuX/sacrebleu/setup.p
  y'&quot;'&quot;'; __file__='&quot;'&quot;'/tmp/pip-install-HCHhuX/sacrebleu/setup.py'&quot;'&quot;';f=getattr(tokenize, '&quot;'&quot;'open'&quot;'&quot;', open)(__file__);code=f
  .read().replace('&quot;'&quot;'\r\n'&quot;'&quot;', '&quot;'&quot;'\n'&quot;'&quot;');f.close();exec(compile(code, __file__, '&quot;'&quot;'exec'&quot;'&quot;'))' egg_info --egg-base /tmp/
  pip-install-HCHhuX/sacrebleu/pip-egg-info
           cwd: /tmp/pip-install-HCHhuX/sacrebleu/
      Complete output (7 lines):
      Traceback (most recent call last):
        File &quot;&lt;string&gt;&quot;, line 1, in &lt;module&gt;
        File &quot;/tmp/pip-install-HCHhuX/sacrebleu/setup.py&quot;, line 65, in &lt;module&gt;
          version = get_version(),
        File &quot;/tmp/pip-install-HCHhuX/sacrebleu/setup.py&quot;, line 56, in get_version
          with open(os.path.join(os.path.dirname(__file__), 'sacrebleu.py'), encoding='utf-8') as fin:
      TypeError: 'encoding' is an invalid keyword argument for this function
      ----------------------------------------
  ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
  WARNING: You are using pip version 20.0.2; however, version 20.1.1 is available.
  You should consider upgrading via the '/usr/bin/python -m pip install --upgrade pip' command.
  </code></pre>
  <p>How can I realize <code>pip3 install -r requirements.txt</code>? Could you give me any advice, please?</p>