refactor: replace incron with systemd.path

.github/workflows/bionic/Dockerfile

@@ -18,7 +18,6 @@ RUN apt-get update \
     git \
     build-essential \ 
     git \
-    incron \
     nginx \
     python3-pip \
     python3-click \

.github/workflows/bullseye/Dockerfile

@@ -18,7 +18,6 @@ RUN apt-get update \
     git \
     build-essential \ 
     git \
-    incron \
     nginx \
     python3-pip \
     python3-click \

.github/workflows/buster/Dockerfile

@@ -18,7 +18,6 @@ RUN apt-get update \
     git \
     build-essential \ 
     git \
-    incron \
     nginx \
     python3-pip \
     python3-click \

.github/workflows/focal/Dockerfile

@@ -18,7 +18,6 @@ RUN apt-get update \
     git \
     build-essential \ 
     git \
-    incron \
     nginx \
     python3-pip \
     python3-click \

README.md

@@ -16,8 +16,6 @@ The tiniest Heroku/CloudFoundry-like PaaS you've ever seen.
 
 The current plan is to throw up a warning for older runtimes and do regression testing for 3.7, 3.8, 3.9 and 3.10 (replacing the current bracket of tests from 3.5 to 3.8)
 
-> **Note:** `piku` currently does not run on Debian 11 (`bullseye`) since the `incron` package has been removed from the distro. We are evaluating using [a custom `systemd.path` unit](https://www.freedesktop.org/software/systemd/man/systemd.path.html) (and accepting contributions for it).
-
 ## Goals and Motivation
 
 I kept finding myself wanting an Heroku/CloudFoundry-like way to deploy stuff on a few remote ARM boards and [my Raspberry Pi cluster][raspi-cluster], but since [dokku][dokku] didn't work on ARM at the time and even `docker` can be overkill sometimes, I decided to roll my own.

docs/INSTALL.md

@@ -227,12 +227,15 @@ sudo service uwsgi-piku start
 *PLEASE NOTE:* There is a bug in `nginx` 1.6.2 under Raspbian 8 that causes it to try to allocate around a gigabyte of RAM when using SSL with SPDY. I seriously recommend using Ubuntu instead, if you can, or disabling SSL altogether.
 
 ```bash
-sudo apt-get install nginx incron
 # Set up nginx to pick up our config files
 sudo cp /tmp/nginx.default.dist /etc/nginx/sites-available/default
-# Set up incron to reload nginx upon config changes
-sudo cp /tmp/incron.dist /etc/incron.d/piku
-sudo systemctl restart incron
+# Set up systemd.path to reload nginx upon config changes
+sudo cp ./piku-nginx.{path, service} /etc/systemd/system/
+sudo systemctl enable piku-nginx.{path,service}
+sudo systemctl start piku-nginx.path
+# Check the status of piku-nginx.service
+systemctl status piku-nginx.path # should return `Active: active (waiting)`
+# Restart NGINX
 sudo systemctl restart nginx
 ```
 

docs/old/RASPBERRY_PI_QUICKSTART.md

@@ -48,7 +48,7 @@ As of April 2016, the shipping versions with Raspbian are recent enough to run `
 
 ```bash
 # as 'pi' user
-sudo apt install -y python-virtualenv python-pip git uwsgi uwsgi-plugin-python incron nginx
+sudo apt install -y python-virtualenv python-pip git uwsgi uwsgi-plugin-python nginx
 sudo pip install -U click
 sudo reboot
 ```
@@ -61,7 +61,7 @@ Clone the [piku repo](https://github.com/piku/piku) somewhere and copy files to
 
 ```bash
 # as yourself in your desktop/laptop computer
-scp piku.py uwsgi-piku.service nginx.default.dist incron.dist pi@your_machine:/tmp
+scp piku.py uwsgi-piku.service nginx.default.dist pi@your_machine:/tmp
 scp your_public_ssh_key.pub pi@your_machine:/tmp
 ```
 
@@ -80,12 +80,16 @@ sudo systemctl enable uwsgi-piku
 Prepare nginx:
 
 ```bash
-sudo apt-get install nginx incron
+sudo apt-get install nginx
 # Set up nginx to pick up our config files
 sudo cp /tmp/nginx.default.dist /etc/nginx/sites-available/default
-# Set up incron to reload nginx upon config changes
-sudo cp /tmp/incron.dist /etc/incron.d/piku
-sudo systemctl restart incron
+# Set up systemd.path to reload nginx upon config changes
+sudo cp ./piku-nginx.{path, service} /etc/systemd/system/
+sudo systemctl enable piku-nginx.{path,service}
+sudo systemctl start piku-nginx.path
+# Check the status of piku-nginx.service
+systemctl status piku-nginx.path # should return `Active: active (waiting)`
+# Restart NGINX
 sudo systemctl restart nginx
 ```
 

docs/old/SCRIPTS.md

@@ -6,21 +6,24 @@ Full installation sequence on a blank Ubuntu 16.04 machine:
 sudo apt-get update
 sudo apt-get -y dist-upgrade
 sudo apt-get -y autoremove
-sudo apt-get install -y tmux vim htop fail2ban uwsgi uwsgi-plugin-python uwsgi-plugin-python3 uwsgi-plugin-asyncio-python3 uwsgi-plugin-gevent-python uwsgi-plugin-tornado-python nginx incron libxml2-dev libxslt1-dev python-dev zlib1g-dev build-essential git python3-virtualenv python3-pip python3-click
+sudo apt-get install -y tmux vim htop fail2ban uwsgi uwsgi-plugin-python uwsgi-plugin-python3 uwsgi-plugin-asyncio-python3 uwsgi-plugin-gevent-python uwsgi-plugin-tornado-python nginx libxml2-dev libxslt1-dev python-dev zlib1g-dev build-essential git python3-virtualenv python3-pip python3-click
 sudo pip3 install -U click pip
 sudo adduser --disabled-password --gecos 'PaaS access' --ingroup www-data piku
 
 # move to /tmp and grab our distribution files
 cd /tmp
 wget https://raw.githubusercontent.com/piku/piku/master/piku.py
-wget https://raw.githubusercontent.com/piku/piku/master/incron.dist
+wget https://raw.githubusercontent.com/piku/piku/master/piku-nginx.path
+wget https://raw.githubusercontent.com/piku/piku/master/piku-nginx.service
 wget https://raw.githubusercontent.com/piku/piku/master/nginx.default.dist
 wget https://raw.githubusercontent.com/piku/piku/master/uwsgi-piku.service
 # Set up nginx to pick up our config files
 sudo cp /tmp/nginx.default.dist /etc/nginx/sites-available/default
-# Set up incron to reload nginx upon config changes
-sudo cp /tmp/incron.dist /etc/incron.d/piku
-sudo systemctl restart incron
+# Set up systemd.path to reload nginx upon config changes
+sudo cp ./piku-nginx.{path, service} /etc/systemd/system/
+sudo systemctl enable piku-nginx.{path,service}
+sudo systemctl start piku-nginx.path
+# Restart NGINX
 sudo systemctl restart nginx
 sudo cp /tmp/uwsgi-piku.service /etc/systemd/system/
 # refer to our executable using a link, in case there are more versions installed

docs/raspbian-9.4-stretch-10-buster.md

@@ -31,7 +31,7 @@ At this point it is a good idea to `sudo shutdown -h now` and make a backup imag
 Before installing `piku`, you need to install the following packages:
 
 ```bash
-sudo apt-get install -y build-essential certbot git incron \
+sudo apt-get install -y build-essential certbot git \
     libjpeg-dev libxml2-dev libxslt1-dev zlib1g-dev nginx \
     python-certbot-nginx python-dev python-pip python-virtualenv \
     python3-dev python3-pip python3-click python3-virtualenv \
@@ -103,15 +103,18 @@ server {
 include /home/PAAS_USERNAME/.piku/nginx/*.conf;
 ```
 
-## `incron` Configuration
-
-To detect configuration changes and tell `nginx` to activate new `piku` sites, we use `incron`. Create `/etc/incron.d/paas` with the following contents:
+## Set up systemd.path to reload nginx upon config changes
 
 ```bash
-# replace `PAAS_USERNAME` with the username you created.
-/home/PAAS_USERNAME/.piku/nginx IN_MODIFY,IN_NO_LOOP /bin/systemctl reload nginx
+# Set up systemd.path to reload nginx upon config changes
+sudo cp ./piku-nginx.{path, service} /etc/systemd/system/
+sudo systemctl enable piku-nginx.{path,service}
+sudo systemctl start piku-nginx.path
+# Check the status of piku-nginx.service
+systemctl status piku-nginx.path # should return `Active: active (waiting)`
+# Restart NGINX
+sudo systemctl restart nginx
 ```
-
 ## Notes
 
 > This file was last updated on June 2019

docs/ubuntu-18.04-bionic.md

@@ -10,7 +10,7 @@ Before installing `piku`, you need to install the following packages:
 
 ```bash
 sudo apt-get update
-sudo apt-get install -y build-essential certbot git incron \
+sudo apt-get install -y build-essential certbot git \
     libjpeg-dev libxml2-dev libxslt1-dev zlib1g-dev nginx \
     python-certbot-nginx python-dev python-pip python-virtualenv \
     python3-dev python3-pip python3-click python3-virtualenv \
@@ -79,13 +79,17 @@ server {
 include /home/PAAS_USERNAME/.piku/nginx/*.conf;
 ```
 
-## `incron` Configuration
-
-To detect configuration changes and tell `nginx` to activate new `piku` sites, we use `incron`. Create `/etc/incron.d/paas` with the following contents:
+## Set up systemd.path to reload nginx upon config changes
 
 ```bash
-# replace `PAAS_USERNAME` with the username you created.
-/home/PAAS_USERNAME/.piku/nginx IN_MODIFY,IN_NO_LOOP /bin/systemctl reload nginx
+# Set up systemd.path to reload nginx upon config changes
+sudo cp ./piku-nginx.{path, service} /etc/systemd/system/
+sudo systemctl enable piku-nginx.{path,service}
+sudo systemctl start piku-nginx.path
+# Check the status of piku-nginx.service
+systemctl status piku-nginx.path # should return `Active: active (waiting)`
+# Restart NGINX
+sudo systemctl restart nginx
 ```
 
 ## Notes

img/piku.dot

@@ -3,7 +3,7 @@ digraph G {
     graph [ dpi = 300 ]; 
     bgcolor=transparent;
     truecolor=true;
-    {rank=same;sshd;uwsgie;nginx;incron;}
+    {rank=same;sshd;uwsgie;nginx;}
     //rankdir=LR;
     subgraph uwsgi_tree {
         uwsgie [label="uwsgi" style=filled fillcolor=white fontname="Arial"];
@@ -46,10 +46,4 @@ digraph G {
         nginx->nginx_confd [arrowhead=none style=dashed];
         nginx_confd->nginx_conf [arrowhead=none style=dashed];
     }
-    subgraph incron_tree {
-        incron [fontname="Arial" style=filled fillcolor=white];
-        nginx_conf -> incron [label="watch", style="dotted", fontname="Arial" weight=0]; 
-        incron -> nginx [label="reload" style="dotted" fontname="Arial" weight=0];
-        incron->nginx_conf [style=invis];
-    }
 }

incron.dist

@@ -1 +0,0 @@
-/home/piku/.piku/nginx IN_MODIFY,IN_NO_LOOP /bin/systemctl reload nginx

piku-nginx.path

@@ -0,0 +1,9 @@
+[Unit]
+Description=Monitor .piku/nginx for changes
+
+[Path]
+PathChanged=/home/piku/.piku/nginx
+Unit=piku-nginx.service
+
+[Install]
+WantedBy=multi-user.target

piku-nginx.service

@@ -0,0 +1,9 @@
+[Unit]
+Description=Restarts NGINX when .piku/nginx changes.
+
+[Service]
+Type=simple
+ExecStart=/bin/systemctl reload nginx
+
+[Install]
+WantedBy=multi-user.target