Merge pull request #221 from dephell/improve-installer

install dephell from current branch on TravisCI

.travis.yml

@@ -9,7 +9,7 @@ before_install:
   # install DepHell
   # - curl https://raw.githubusercontent.com/dephell/dephell/master/install.py | /opt/python/3.6/bin/python
   # https://github.com/travis-ci/travis-ci/issues/8589
-  - /opt/python/3.7/bin/python install.py
+  - /opt/python/3.7/bin/python install.py --branch=$TRAVIS_PULL_REQUEST_BRANCH
   - dephell inspect self
 install:
   - dephell venv create --env=$ENV --python="/opt/python/$TRAVIS_PYTHON_VERSION/bin/python" --level=DEBUG --traceback

docs/installation.md

@@ -6,7 +6,7 @@ Recommend way:
 curl https://raw.githubusercontent.com/dephell/dephell/master/install.py | python3
 ```
 
-It will install DepHell into DepHell's jail ([WE NEED TO GO DEEPER](https://knowyourmeme.com/memes/we-need-to-go-deeper)). However, this script experimental. So, in the project's README presented other way:
+It will install DepHell into DepHell's jail ([WE NEED TO GO DEEPER](https://knowyourmeme.com/memes/we-need-to-go-deeper)). This link looks too long, so in the project's README represented another way:
 
 ```bash
 python3 -m pip install --user dephell[full]
@@ -20,6 +20,15 @@ python3 -m pip install --user dephell
 
 ## Get development version
 
+Install dev version inside of site-packages:
+
+```bash
+wget https://raw.githubusercontent.com/dephell/dephell/master/install.py
+python3 install.py --branch=master
+```
+
+Or get whole project and teach Python to use it:
+
 ```bash
 $ git clone https://github.com/dephell/dephell.git
 $ cd dephell

install.py

@@ -1,10 +1,18 @@
 # built-in
 import subprocess
+from argparse import ArgumentParser
 from os import environ, pathsep
 from pathlib import Path
 from venv import create
 
 
+# parse CLI arguments
+parser = ArgumentParser()
+parser.add_argument('--branch', help='install dephell from git from given branch')
+parser.add_argument('--version', help='install specified version')
+args = parser.parse_args()
+
+
 # install pip
 try:
     import pip  # noQA: F401
@@ -48,7 +56,14 @@ def get_data_dir() -> Path:
 
 
 print('install dephell')
-result = subprocess.run([str(python_path), '-m', 'pip', 'install', 'dephell[full]'])
+if args.branch:
+    name = 'git+https://github.com/dephell/dephell.git@{branch}#egg=dephell[full]'
+    name = name.format(branch=args.version or args.branch)
+elif args.version:
+    name = 'dephell[full]=={version}'.format(version=args.version)
+else:
+    name = 'dephell[full]'
+result = subprocess.run([str(python_path), '-m', 'pip', 'install', name])
 if result.returncode != 0:
     exit(result.returncode)