fdpCloud

General-purpose Linked Data server, named for Fair Data Points.

Tools

Apache2

Standard Apache2 server with these additional modules enabled with e.g. a2enmod proxy_http

proxy
proxy_http
ssl
maybe socache_shmcb.load ? don't know how that got there.

The 000-default config in /etc/apache/sites-enabled is removed; replaced with: fdpcloud.org.conf -> ../sites-available/fdpcloud.org.conf

If you modify configs or modules run this as root: apachectl graceful.

subdomain config

Subdomains are included in the /etc/apache2/sites-available/subdomains.d/ directory. They connects a valid domain name (all lowercase) with a possibly mixed-case path to the contents. The example below is for a subdomain called flashcard:

<VirtualHost *:80>
  ServerName flashcard1.fdpcloud.org
  DocumentRoot /home/fdpCloud/sites/github/StaticFDP/FlashCard1
  <Directory /home/fdpCloud/sites/github/StaticFDP/FlashCard1>
    include ./sites-available/fdpcloud-dirConfig
  </Directory>
  include ./sites-available/fdpcloud-common
</VirtualHost>

<VirtualHost *:443>
  ServerName flashcard1.fdpcloud.org
  DocumentRoot /home/fdpCloud/sites/github/StaticFDP/FlashCard1
  <Directory /home/fdpCloud/sites/github/StaticFDP/FlashCard1>
    include ./sites-available/fdpcloud-dirConfig
  </Directory>
  include ./sites-available/fdpcloud-ssl
  include ./sites-available/fdpcloud-common
</VirtualHost>

The repo contents are, of course, available at that subdomain (e.g. flashcard1.fdpcloud.org) as well as the directory (e.g. fdpcloud.org/sites/github/StaticFDP/FlashCard1/).

webhook

Debian package to handle webhooks; runs on localhost:9000. An apache reverse proxy shuttles requests to it.

Certbot

Needs attention every 3 months. This will prompt you to write to the DNS record:

sudo certbot certonly --manual \
 --preferred-challenges=dns \
 --email webmaster@fdpcloud.org \
 --server https://acme-v02.api.letsencrypt.org/directory \
 --agree-tos \
 -d fdpcloud.org -d *.fdpcloud.org

screen

General-purpose screen multiplexer. The standard config set up below under [#reboot/start] sets up consoles for maintanance and debugging. Here's how to invoke screen:

Description	Command
Start a new session with session name	`screen -US <session_name>`
List running sessions / screens	`screen -ls`
Attach to a running session	`screen -x`

The (default) attention key is control a (^a below). Here are the commands used below:

Description	Command
Create new window	`^a c`
Change to window by number	`Ctrl-a <number>` (only for windows 0 to 9)
See window list	`^a "` (allows you to select a window to change to)
Show window bar	`^a w` (if you don't have window bar)

^a " is very cool; try it.

See Screen Quck Reference for more tips.

You typically finish a session by detaching from screen with ^a d before logging out or closing your terminal window.

Debian packages

name	version	architecture	description
apache2	2.4.52-1ubuntu4.6	amd64	Apache HTTP Server
apache2-bin	2.4.52-1ubuntu4.6	amd64	Apache HTTP Server (modules and other binary files)
apache2-data	2.4.52-1ubuntu4.6	all	Apache HTTP Server (common files)
apache2-utils	2.4.52-1ubuntu4.6	amd64	Apache HTTP Server (utility programs for web servers)
python3-certbot-apache	1.21.0-1	all	Apache plugin for Certbot
webhook	2.8.0-3	amd64	Small server for creating HTTP endpoints (hooks)

Tasks

connect to screen

ssh fdpcloud.org
sudo su -
  screen -x console              # screen window 0 watches webhook

If you see "There is no screen to be attached matching console.", you need to [#start screen] (see below). You can type ^a " to see what windows are running in the screen. You should see:

Num Name                                        Flags

   0 webhhook monitor                                $
   1 add repos                                       $
   2 Apache.conf                                     $
   3 Apache control                                  $

add repo

create repo (possibly under StaticFDP)
copy HTTPS URL from Code button but chop skip the trailing .git (e.g. https://github.com/StaticFDP/FlashCard1)

ssh fdpcloud.org
sudo su -
screen -x console
^a1 # webhook monitor window
  (cd github/ && git clone https://github.com/StaticFDP/wikidata StaticFDP/FlashCard1)
^a2 # add repos window
  # use editor or whatever to create virtual host entries for e.g. `flashcard1`; see subdomain config above.
^a3 # Apache.conf window
  apachectl graceful

Go back to repo and create a webhook (Settings Webhhoks)
- Payload URL: https://fdpCloud.org/HOOKS/updateFromGithub
- Content type: application/json
- Secret: yJJON3k6tT - - - yes, same for everyone. could change to "NoDOSPlease"
- ☑ Enable SSL verification
- ☑ just the push event
- ☑ Active
- [Update Webhook]

This should immediate fire a push webhook. you can see the results in the webhook monitor (^a0) window.

reboot/start

$ restart

... a browser reload will tell you when Apache has restarted ...

ssh fdpcloud.org
sudo su -
  screen -US console              # screen window 0 watches webhook
    ^aA ^h^h^h^hwebhook monitor
    sudo su - fdpCloud
      webhook -debug hooks.json
  ^ac                             # screen window 1 is for adding repos
    ^aA ^h^h^h^hadd repos
    cd sites/
  ^ac # screen window 2 is for editing Apache conf
    ^aA ^h^h^h^hApache.conf
    emacs /etc/apache2/sites-enabled/fdpcloud.org.conf
  ^ac # screen window 3 is for restarting Apache
    ^aA ^h^h^h^hApache control

install

Install node and npm for everyone per SO. (The Ubuntu nodejs package is ancient and the npm package has every dependcy.)

npm ci of LdHostManager got a gyp error for nodegit (presumably):

npm ERR! /bin/sh: 1:
npm ERR! krb5-config: not found
npm ERR! 
npm ERR! gyp: Call to 'krb5-config gssapi --libs' returned exit status 127 while in binding.gyp. while trying to load binding.gyp

Rectify with

sudo apt-get install libkrb5-dev -y

npm ci takes 10s of minutes so periodically hit the return keep to keep the connection from timing out.

AmsterdamUMC/fdpCloud