Install prerequisites

Oppia relies on a number of programs and third-party libraries. Many of these libraries are downloaded automatically for you when you first run the start.py script provided with Oppia (see step 1 in the next section). However, there are some things that you will need to do beforehand:

Update your package list to the latest version by running:

sudo apt-get update

Make sure you have curl (used to download third-party libraries), setuptools (needed for installing coverage, which checks test coverage for the Python code), git (which allows you to store the source in version control), python-dev (which is used for the numpy installation), python-pip (which is also used for the numpy installation), pyyaml (which is used to parse YAML files) and libbz2-dev (used by Apache Beam):

sudo apt-get install python3-pip python3-setuptools curl openjdk-8-jre git python3-dev python3-yaml python3-matplotlib unzip libbz2-dev

Alternatively, if you are on Debian/Ubuntu, you can use the install_prerequisites.sh script to install these. From the oppia directory:

bash scripts/install_prerequisites.sh

Make sure that you have Python 2 installed, it is needed for the dev server to run. On Ubuntu 20 you can install it using sudo apt install python2.
Install Chrome from Google's website. You'll need this to run tests.

Clone Oppia

Create a new, empty folder that will hold your Oppia work. Here, we call the folder opensource.
Navigate to the folder (cd opensource/). Next, we'll fork and clone the Oppia repository.
Navigate to https://github.com/oppia/oppia and click on the fork button. It is placed on the right corner opposite the repository name oppia/oppia.

You should now see Oppia under your repositories. It will be marked as forked from oppia/oppia.

Clone the repository to your local computer (replacing the values in {{}}):

$ git clone https://github.com/{{GITHUB USERNAME}}/oppia.git
Cloning into 'oppia'...
remote: Enumerating objects: 203313, done.
remote: Total 203313 (delta 0), reused 0 (delta 0), pack-reused 203313
Receiving objects: 100% (203313/203313), 179.26 MiB | 3.12 MiB/s, done.
Resolving deltas: 100% (155851/155851), done.
Updating files: 100% (4199/4199), done.

Note that you will see slightly different output because the numbers change as Oppia grows.

Now your origin remote is pointing to your fork ({{GITHUB USERNAME}}/oppia). To stay up to date with the main oppia/oppia repository, add it as a remote called upstream. You'll first need to move into the oppia directory that was created by the clone operation.
```
$ cd oppia
$ git remote add upstream https://github.com/oppia/oppia.git
$ git remote -v
origin     https://github.com/{{GITHUB USERNAME}}/oppia.git (fetch)
origin     https://github.com/{{GITHUB USERNAME}}/oppia.git (push)
upstream   https://github.com/oppia/oppia.git (fetch)
upstream   https://github.com/oppia/oppia.git (push)
```
The git remote -v command at the end shows all your current remotes.

Now you can pull in changes from oppia/oppia by running git pull upstream {{branch}} and push your changes to your fork by running git push origin {{branch}}.

We have established a clean setup now. We can make any changes we like and push it to this forked repository, and then make a pull request for getting the changes merged into the original repository. Here's a nice picture explaining the process (image source).

For making any changes to original repository, we first sync our cloned repository with original repository. We merge develop with upstream/develop to do this. Now we make a new branch, do the changes on the branch, push the branch to forked repository, and make a PR from Github interface. We use a different branch to make changes so that we can work on multiple issues while still having a clean version in develop branch.

Setup a virtual environment

For your virtual environment, we recommend you use pyenv. Here are some instructions for doing so, but you can use another virtual environment tool if you wish:

Make sure you install the Python build dependencies for your operating system. These are specified here. If you don't do this it might lead to problems further on. The build dependencies for Ubuntu/Debian are

sudo apt-get install make build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev wget llvm libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev

Install pyenv:

$ curl pyenv.run | bash
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   270  100   270    0     0    630      0 --:--:-- --:--:-- --:--:--   632
Cloning into '/home/user/.pyenv'...
...
WARNING: seems you still have not added 'pyenv' to the load path.
...

If you see the warning at the end, add the following lines to your ~/.bashrc (if you are using bash) or ~/.zshrc (if you are using zsh).

export PYENV_ROOT="$HOME/.pyenv"
export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init --path)"

eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"

Warning Be careful with using graphical editors like Notepad in Windows. These can add carriage returns (\r) that confuse our Linux-based development tools. Instead, we recommend using editors designed for programming or command-line text editors.

Reload your shell or open a new terminal window to load your updated ~/.bashrc or ~/.zshrc.

Now you can install Python 3.8.15 and the associated pip like this:

$ pyenv install 3.8.15
installing python-3.8.15...
patching file misc/news.d/next/build/2021-10-11-16-27-38.bpo-45405.isfdw5.rst
patching file configure
patching file configure.ac
installed python-3.8.15 to /home/user/.pyenv/versions/3.8.15

Install direnv
```
$ sudo apt install direnv
```
Setup direnv into your shell.
If you are using bash, add following lines to the end of ~/.bashrc.
```
eval "$(direnv hook bash)"
```
If you are using zsh, add following lines to the end of ~/.zshrc.
```
eval "$(direnv hook zsh)"
```
Warning Be careful with using graphical editors like Notepad in Windows. These can add carriage returns (\r) that confuse our Linux-based development tools. Instead, we recommend using editors designed for programming or command-line text editors.
Add new file called .direnvrc into your home (~) folder with this content:
```
use_python() {
  local python_root=$(pyenv root)/versions/$1
  load_prefix "$python_root"
  if [[ -x "$python_root/bin/python" ]]; then
    layout python "$python_root/bin/python"
  else
    echo "Error: $python_root/bin/python can't be executed."
    exit
  fi
}
```
Warning Be careful with using graphical editors like Notepad in Windows. These can add carriage returns (\r) that confuse our Linux-based development tools. Instead, we recommend using editors designed for programming or command-line text editors.
Create a virtual environment for oppia by adding file named .envrc into the parent folder of the oppia repository with this content:
```
use python 3.8.15
```
Then run this command in the same folder:
```
$ direnv allow
```
Now whenever you are within the oppia folder, the virtual environment will be active.

Install the Python dependencies:

$ pip install pyyaml setuptools
Requirement already satisfied: setuptools in /home/user/.pyenv/versions/2.7.18/envs/oppia-tmp/lib/python2.7/site-packages (44.1.1)
Collecting pyyaml
  Downloading PyYAML-5.4.1-cp27-cp27mu-manylinux1_x86_64.whl (574 kB)
     |████████████████████████████████| 574 kB 2.3 MB/s
Installing collected packages: pyyaml
Successfully installed pyyaml-5.4.1

Note that you don't need to install pyyaml if you were able to install python-yaml with your package manager earlier.

If you want to run backend tests and check coverage, please install these 2 pip libraries:
```
pip install coverage configparser
```

Running Oppia on a development server

In a terminal, navigate to oppia/ and run:
```
python -m scripts.start
```
Note If you are using Windows, you will need to run python -m scripts.start --no_browser instead. This is because Windows does not support the xdg-open command that the script uses to open a browser window.

The first time you run this script, it will take a while -- about 5 - 10 minutes when we last tested it in Sep 2020, though this depends on your Internet connection. (It might also hang after "Checking if pip is installed on the local machine" due to the grpcio build being slow -- just give it some time, and it should finish.) Subsequent runs should be much faster. The start.py script downloads and installs the required dependencies (such as Google App Engine) if they are not already present, and sets up a development server for you to play with. The development server logs are then output to this terminal, so you will not be able to enter further commands in it until you disconnect the server.

Note Please don't use sudo while installing. It's not required, and using it may cause problems later. If you face permissions issues, ensure that you have the necessary permissions for the directory in which you're trying to set up Oppia. If you run into any other installation problems, please read these notes.

Note The script will create two folders that are siblings of the oppia/ root directory: oppia_tools and node_modules. This is done so that these two folders will not be uploaded to App Engine when the application is deployed to the web.

Note If you run into errors while installing Oppia, please try running python -m scripts.clean and running start.py again.

Note Oppia uses the npm tool to install some packages. This tool accesses both ~/tmp and ~/.npm, and has been known to occasionally encounter permissions issues with those directories. You may need to either delete these directories and all their contents (if they do not contain anything else that needs to be preserved), or change their permissions so that they are owned by you, which you can do by running
```
sudo chown -R {{YOUR_USERNAME}} ~/tmp
sudo chown -R {{YOUR_USERNAME}} ~/.npm
```
where {{YOUR_USERNAME}} should be replaced by your username.
The start.py script will start a development server at http://localhost:8181. It should look something like this:

You can also view the App Engine admin console at http://localhost:8000.

Note: There may be a few warnings that appear after running start.py. Don’t worry about these so long as you see the page above once you go to http://localhost:8181. The script should continue to run so long as the development server is on (you’ll see a lot of lines that start with "INFO") and you’re able to navigate to the page.

When you're done, you can shut down the development server by typing Ctrl+C into the terminal. Then wait for a command prompt to appear. Oppia has to shut down all the services it's started, and if you abort the graceful shutdown steps (e.g. by typing Ctrl+C many times), you may have trouble re-starting the server.

Example shutdown output

^CINFO     2021-07-19 00:31:32,627 shutdown.py:50] Shutting down.
INFO     2021-07-19 00:31:32,627 stub_util.py:377] Applying all pending transactions and saving the datastore
INFO     2021-07-19 00:31:32,628 stub_util.py:380] Saving search indexes

i  emulators: Received SIGINT (Ctrl-C) for the first time. Starting a clean shutdown.
i  emulators: Please wait for a clean shutdown or send the SIGINT (Ctrl-C) signal again to stop right now.
i  Automatically exporting data using --export-on-exit "/opensource/oppia/../firebase_emulator_cache" please wait for the export to finish...


Servers are shutting down, please wait for them to end gracefully!


i  Found running emulator hub for project dev-project-id at http://localhost:4400
i  Creating export directory /opensource/firebase_emulator_cache
i  Exporting data to: /opensource/firebase_emulator_cache
i  emulators: Received export request. Exporting data to /opensource/firebase_emulator_cache.
✔  emulators: Export complete.
✔  Export complete
i  emulators: Shutting down emulators.
i  ui: Stopping Emulator UI
⚠  Emulator UI has exited upon receiving signal: SIGINT
i  auth: Stopping Authentication Emulator
i  hub: Stopping emulator hub
i  logging: Stopping Logging Emulator
Stopping Web Browser(name="xdg-open", pid=14416)...
Stopping GAE Development Server(name="sh", pid=14405)...
Stopping Webpack Compiler(name="sh", pid=14338)...
Stopping Firebase Emulator(name="sh", pid=14311)...
Stopping ElasticSearch Server(name="sh", pid=14060)...
Stopping Redis Server(name="sh", pid=14045)...


Done! Thank you for waiting.


Traceback (most recent call last):
  File "/home/user/.pyenv/versions/2.7.18/lib/python2.7/runpy.py", line 174, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/home/user/.pyenv/versions/2.7.18/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/opensource/oppia/scripts/start.py", line 202, in <module>
    main()
  File "/opensource/oppia/scripts/start.py", line 198, in main
    dev_appserver.wait()
  File "/opensource/oppia/../oppia_tools/psutil-5.7.3/psutil/__init__.py", line 1350, in wait
    ret = super(Popen, self).wait(timeout)
  File "/opensource/oppia/../oppia_tools/psutil-5.7.3/psutil/__init__.py", line 1259, in wait
    self._exitcode = self._proc.wait(timeout)
  File "/opensource/oppia/../oppia_tools/psutil-5.7.3/psutil/_pslinux.py", line 1517, in wrapper
    return fun(self, *args, **kwargs)
  File "/opensource/oppia/../oppia_tools/psutil-5.7.3/psutil/_pslinux.py", line 1725, in wait
    return _psposix.wait_pid(self.pid, timeout, self._name)
  File "/opensource/oppia/../oppia_tools/psutil-5.7.3/psutil/_psposix.py", line 115, in wait_pid
    retpid, status = os.waitpid(pid, flags)
KeyboardInterrupt

Tips and tricks

To preserve the contents of the local datastore between consecutive runs, use the --save_datastore argument when starting up the dev server:
```
python -m scripts.start --save_datastore
```
The default Oppia installation comes with a set of demo explorations. On startup, none of these are loaded. To load them, log in to your server as an admin, then click your username in the top-right corner and choose 'Admin Page'. This will open the admin page, from which you can load the demo explorations.

Notes on installation on Arch Linux systems

The following notes are thanks to @ashish-patwal. They come with no guarantees, and may change some settings on your local machine, so please make sure you fully understand their ramifications before following them!

Changes to installation prerequisites

Arch uses pacman as its package manager, so the install_prerequisites.sh script is not going to work. Instead, all of the prerequisites have to be installed manually using pacman. Just type the following command in the shell (notation: # denotes sudo access while $ denotes normal user access):

# pacman -Sy curl jre8-openjdk python-setuptools git python-pip python-yaml unzip python-matplotlib

Also, note that pacman doesn't support Google Chrome (which is needed to run frontend and end-to-end tests) in the default package manager. However, you can use the chromium package instead; chromium is the open-source core of Google Chrome. Install the chromium browser and then create a soft link from the google-chrome command to chromium:

# pacman -Sy chromium
# cd /usr/bin
# ln -sf chromium google-chrome

Changes to the virtual environment setup

On Arch Linux, you should follow these instructions to set up your virtual environment:

Make sure you install the Python build dependencies for your operating system. These are specified here. If you don't do this it might lead to problems further on.

Install pyenv (notation: # denotes sudo access while $ denotes normal user access):

# pacman -S pyenv

Install pyenv-virtualenv either with yay or pacaur:

$ yay -S pyenv-virtualenv

$ pacaur -S pyenv-virtualenv

Bash / Zsh

Add the following lines to your ~/.bashrc or .zshrc

export PYENV_ROOT="$HOME/.pyenv"
export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init --path)"

eval "$(pyenv init -)"
eval "$(pyenv virtualenv-init -)"

Fish

Execute this interactively :

set -Ux PYENV_ROOT $HOME/.pyenv
set -U fish_user_paths $PYENV_ROOT/bin $fish_user_paths

And add this to ~/.config/fish/config.fish

status is-interactive; and pyenv init --path | source
pyenv init - | source
eval "$(pyenv virtualenv-init -)"

Reload your shell or open a new terminal window to load your updated .bashrc, .zshrc, or config.fish

Now you can install Python 3.8.15 and the associated pip like this:

$ pyenv install 3.8.15
installing python-3.8.15...
patching file misc/news.d/next/build/2021-10-11-16-27-38.bpo-45405.isfdw5.rst
patching file configure
patching file configure.ac
installed python-3.8.15 to /home/user/.pyenv/versions/3.8.1

Create a virtual environment for oppia:
```
$ pyenv virtualenv 3.8.15 oppia
...
$ pyenv versions
...
oppia
...
```
In the cloned oppia folder, run
```
pyenv local oppia
```
Now whenever you are within the oppia folder, the virtual environment will be active.

Install the Python dependencies:

$ pip install pyyaml setuptools
Requirement already satisfied: setuptools in /home/user/.pyenv/versions/2.7.18/envs/oppia-tmp/lib/python2.7/site-packages (44.1.1)
Collecting pyyaml
  Downloading PyYAML-5.4.1-cp27-cp27mu-manylinux1_x86_64.whl (574 kB)
     |████████████████████████████████| 574 kB 2.3 MB/s
Installing collected packages: pyyaml
Successfully installed pyyaml-5.4.1

Note that you don't need to install pyyaml if you were able to install python-yaml with your package manager earlier.

If you want to run backend tests and check coverage, please install these 2 pip libraries:
```
pip install coverage configparser
```

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Installing-Oppia-(Linux;-Python-3).md

Installing-Oppia-(Linux;-Python-3).md

Table of Contents

Install prerequisites

Clone Oppia

Setup a virtual environment

Running Oppia on a development server

Tips and tricks

Notes on installation on Arch Linux systems

Changes to installation prerequisites

Changes to the virtual environment setup

Files

Installing-Oppia-(Linux;-Python-3).md

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Installing-Oppia-(Linux;-Python-3).md

File metadata and controls

Table of Contents

Install prerequisites

Clone Oppia

Setup a virtual environment

Running Oppia on a development server

Tips and tricks

Notes on installation on Arch Linux systems

Changes to installation prerequisites

Changes to the virtual environment setup