Make Python3.7 default and upgrade conda

bootstrap/bootstrap.py

@@ -113,7 +113,11 @@ def main():
     logger.setLevel(logging.DEBUG)
 
     logger.info('Checking if TLJH is already installed...')
+    python3_version = "python3"
     if os.path.exists(os.path.join(hub_prefix, 'bin', 'python3')):
+        # Check if the existing install is under Python3.7
+        if os.path.exists(os.path.join(hub_prefix, 'bin', 'python3.7')):
+            python3_version = "python3.7"
         logger.info('TLJH already installed, upgrading...')
         initial_setup = False
     else:
@@ -130,14 +134,15 @@ def main():
 
         run_subprocess(['apt-get', 'update', '--yes'])
         run_subprocess(['apt-get', 'install', '--yes', 
-            'python3',
-            'python3-venv',
+            'python3.7',
+            'python3.7-venv',
+            'python3.7-dev',
             'python3-pip',
             'git'
         ])
         logger.info('Installed python & virtual environment')
         os.makedirs(hub_prefix, exist_ok=True)
-        run_subprocess(['python3', '-m', 'venv', hub_prefix])
+        run_subprocess(['python3.7', '-m', 'venv', hub_prefix])
         logger.info('Set up hub virtual environment')
 
     if initial_setup:
@@ -161,9 +166,9 @@ def main():
 
     logger.info('Starting TLJH installer...')
     os.execv(
-        os.path.join(hub_prefix, 'bin', 'python3'),
+        os.path.join(hub_prefix, 'bin', python3_version),
         [
-            os.path.join(hub_prefix, 'bin', 'python3'),
+            os.path.join(hub_prefix, 'bin', python3_version),
             '-m',
             'tljh.installer',
         ] + sys.argv[1:]

tljh/installer.py

@@ -237,8 +237,14 @@ def ensure_user_environment(user_requirements_txt_file):
     Set up user conda environment with required packages
     """
     logger.info("Setting up user environment...")
-    miniconda_version = '4.5.4'
-    miniconda_installer_md5 = "a946ea1d0c4a642ddf0c3a26a18bb16d"
+    if "python3.7" in sys.executable:
+        conda_version = '4.7.5'
+        miniconda_version = '4.7.5'
+        miniconda_installer_md5 = "fc3595e7a66cf159a9d288a212834127"
+    else:
+        conda_version = '4.5.8'
+        miniconda_version = '4.5.4'
+        miniconda_installer_md5 = "a946ea1d0c4a642ddf0c3a26a18bb16d"
 
     if not conda.check_miniconda_version(USER_ENV_PREFIX, miniconda_version):
         logger.info('Downloading & setting up user environment...')
@@ -247,7 +253,7 @@ def ensure_user_environment(user_requirements_txt_file):
 
     conda.ensure_conda_packages(USER_ENV_PREFIX, [
         # Conda's latest version is on conda much more so than on PyPI.
-        'conda==4.5.8'
+        'conda==' + conda_version
     ])
 
     conda.ensure_pip_packages(USER_ENV_PREFIX, [