## http://heliopropa.irap.omp.eu

# What

## Web Server

Build and serve heliopropa's visualizations.

It's a `flask` webserver, serving `d3.js` plots.

It also gathers NetCDF data from AMDA, and serves it as CSV to the plotter.

### Rationale

- Reading NetCDF from javascript is doable, but still *very* hacky.
- The bridge can handle pagination and collecting multiple NetCDF into one CSV.

# How

## Source

https://gitlab.irap.omp.eu/CDPP/SPACEWEATHERONLINE

## Overview

- `config.yml` : the main configuration file.
- `web/run.py` : the front controller, holding most of the code.

- `web/run.log` : you'll find more information about failures in the log.

- `web/view/home.html.jinja2` : the HTML template.

- `web/static/js/swapp.ls` : most of the javascript client-side.

## Install

### Prerequisites
gcc
libncurses-dev

python3
python3-virtualenv
libapache2-mod-wsgi-py3

### Python venv

``` bash

python3 -m venv venv

source venv/bin/activate

pip install matplotlib
pip install numpy==1.8.*

pip install -r requirements.txt
```

### CentOs 6 Shenanigans

``` bash
yum install https://centos6.iuscommunity.org/ius-release.rpm
yum install python27*
```

But then `virtualenv` yields

```
File "/var/www/html/HELIOPROPA/web/run.py", line 24, in <module>
[Fri Nov 30 14:30:38 2018] [error] [client 10.10.135.119]     from netCDF4 import Dataset, date2num
[Fri Nov 30 14:30:38 2018] [error] [client 10.10.135.119]   File "/var/www/html/HELIOPROPA/venv/lib/python2.7/site-packages/netCDF4/__init__.py", line 3, in <module>
[Fri Nov 30 14:30:38 2018] [error] [client 10.10.135.119]     from ._netCDF4 import *
[Fri Nov 30 14:30:38 2018] [error] [client 10.10.135.119] ImportError: /var/www/html/HELIOPROPA/venv/lib/python2.7/site-packages/netCDF4/_netCDF4.so: undefined symbol: PyUnicodeUCS2_FromStringAndSize
```

_Solution:_
Configure Apache to use `web/run_ssa.wsgi` and use pip2.7 install system wide.


### Install libcdf.

``` bash

wget https://spdf.gsfc.nasa.gov/pub/software/cdf/dist/cdf38_1/cdf38_1-dist-all.tar.gz
tar -xzvf cdf38_1-dist-all.tar.gz
cd cdf38_1-dist

make all OS=linux ENV=gnu
make INSTALLDIR=/usr/local/lib/libcdf install
```

## Develop

``` bash
source venv/bin/activate

DEBUG=true python web/run.py

```

Then, browse [localhost:5000](http://localhost:5000).

## Troubleshoot

### Installing scipy

Getting `MemoryErrors` ?
Try with the `--no-cache-dir` option.

`pip install scipy --no-cache-dir`

### Fix permissions problems with the cache

```
sudo setfacl  -R -m u:apache:rwx -m u:`whoami`:rwx cache
sudo setfacl -dR -m u:apache:rwx -m u:`whoami`:rwx cache

```

# Gunicorn and Nginx deployment on OVH for development

see [ Digital Ocean documentation ] (https://www.digitalocean.com/community/tutorials/how-to-serve-flask-applications-with-gunicorn-and-nginx-on-ubuntu-20-04-fr)


## wep app service and Gunicorn

see ./resources/heliopropa.service

/etc/systemd/system/heliopropa.service

    [Unit]
    Description=Gunicorn instance to serve Heliopropa
    After=network.target

    [Service]
    User=debian
    Group=www-data
    WorkingDirectory= /home/debian/heliopropa/
    Environment="PATH=/home/debian/heliopropa/venv/bin/"
    ExecStart=/home/debian/heliopropa/venv/bin/gunicorn --workers 3 --bind unix:heliopropa.sock -m 007 web.run:app

    [Install]
    WantedBy=multi-user.target

## Nginx

see ./resources/heliopropa.nginx

/etc/nginx/sites-available/heliopropa

	server {
		listen 80;
		server_name heliopropa heliopropa.co-libri.org;

		location / {
			include proxy_params;
			proxy_pass http://unix:/home/debian/heliopropa/heliopropa.sock;
		}
	}


## Start and Allow at system reboot

	sudo systemctl start nginx
	sudo systemctl start heliopropa 
	sudo systemctl enable heliopropa 


## Git hook auto deploy

see ./resources/post-receive.git-hook

Set bare repo with hook  on vps

    ssh user@vps
    git clone --bare path-to-heliopropa-repo heliopropa.git
    cd heliopropa.git/hooks
    vim post-receive
    chmod +x post-receive



Push from dev computer

    git remote add helio-dev user@vps:heliopropa.git
    git push heliopropa HEAD:DEV