update Midpoint doc.

midpoint/rtr-midpoint.md

@@ -108,8 +108,7 @@ After you have established a V.M. on A.W.S. or your own server, you
 will need to clone the repository (**I am assuming this is via SSH**).
 
 ```bash
-# Adjust the directories to how you prefer it. These are just my
-defaults.
+# Adjust the directories to how you prefer it. These are just my defaults.
 mkdir www
 cd www
 git clone http://git.abbether.net/return-to-ritherdon/midpoint.git
@@ -163,10 +162,11 @@ the 'connext_app' related to the use of the Swagger API code.
 gunicorn -w 3 server:connex_app
 ```
 
-The -w 3 bit refers to the total number of workers (processors)
+The `-w 3` bit refers to the total number of workers (processors)
 Gunicorn will use whilst running. The general rule to work that out it
-/(number of processors * 2) + 1. At the time of writing, the V.M. is a
-very basic one-core machine so that is why three workers is used.
+/(number of processors * 2) + 1. At the time of writing, the virtual
+machine used for the exhibition is a very basic one-core machine so
+that is why three workers is used.
 
 One problem with Gunicorn is it blocks the terminal when using it in
 its default way. To get around this, I have install Supervisor to
@@ -179,19 +179,21 @@ sudo apt install supervisor
 ```
 
 When Supervisor is installed, you need to create a config. file. The
-file for this project is stored at
-`/etc/supervisor/conf.d/spiapi.conf`. The log files (specified in the
-.conf) file are,
+file for this project is stored at,
+
+- `/etc/supervisor/conf.d/spiapi.conf`
+
+The log files (specified in the .conf) file are,
 
 - `/var/log/midpoint/midpoint.err.log`
 - `/var/log/midpoint/midpoint.out.log`
 
-You will to recreate the directory they are stored in if you are
-installing this site to a new system. The easiest way to do that is to
+You will need to recreate the directory they are stored in if you are
+installing this site on a new system. The easiest way to do that is to
 run the following command,
 
 ```bash
-sudo mkdir -p /var/log/roaming-light-api
+sudo mkdir -p /var/log/midpoint
 sudo touch /var/log/midpoint/midpoint.err.log
 sudo touch /var/log/midpoint/midpoint.out.log
 ```
@@ -206,12 +208,14 @@ sudo supervisor reload
 It might take a little while for the service to restart so if you
 still see "Bad Gateway" messages in the browser, that might be why.
 
-You might find Gunicorn is not installed in the virtual-environment,
-it that is the case, you should find it at,
+You might find Gunicorn is not installed in the virtual-environment
+(if you have decided to not install one or you simply forget to
+activate like I have a habit of doing), it that is the case, you
+should find it at,
 
 - `home/ubuntu.local/bin/gunicorn`
 
-This might, also, mean you need to use apt and not pip3.
+This might, also, mean you need to use `apt` and not `pip3`.
 
 The config. file for Supervisor should look something like the
 following, (remember to adjust the places where `ubuntu` is with your
@@ -252,11 +256,12 @@ username.
 ### Flask & Swagger
 
 To access the A.P.I. user-interface (via Swagger), enter
-`http://0.0.0.0:5000/api/ui/`.
+
+-`http://0.0.0.0:5000/api/ui/`
 
 - [Real Python](https://realpython.com/flask-connexion-rest-api/#using-connexion-to-add-a-rest-api-endpoint)
 
-This site provides a good walk-through for setting-up a website using
+Real Python provides a good walk-through for setting-up a website using
 the Flask framework. Real Python, also, provides guides on creating
 websites with Python and its various website frameworks.
 
@@ -287,8 +292,33 @@ database. To do that, you will need to run the following commands,
 # match your set-up.
 cd ~/www/midpoint/app/
 
+# If you have created and activated a virtual environment, you can
+# enter 'python' instead of 'python3'.
 python3 build-database.py
 ```
 
 This will clear the database if one is already set-up and then build a
 new one.
+
+## Notes on System Limitations
+
+### 1. Connection Times-Out on Large JSON Packets
+
+The biggest thing to remember the REST API calls which grab 'all' the
+light readings from every device, will start to fail fairly quickly
+after a 'clean install'. The reason why is because the JSON package
+becomes too large and the connection times out. You might get better
+results on a more powerfully spec'd server than the one used for the
+exhibition but I have not tested this so I cannot confirm this.
+
+### 2. Three Light-Meters and Relays Specified but Only Two (of each) Used
+
+Ritherdon (the factory) has three welding booths so 'Personal Flash in
+Real-Time' was designed with this in mind. Over the course of the
+development process, the use of the third booth was not
+needed/wanted. By that time, the code, database and models had already
+been created. I decided to opt for the lazy option and keep the
+references to the third booth instead of removing it because it was
+not impeding on the system in any way. I was, also, cautious about the
+chance of a change happening late into the development cycle were I
+would need to put it back it.