Fileserver chapter updated

Fileserver.md

@@ -2,43 +2,47 @@
 
 The fileserver is a simple frontend to a disk storage space that contains 
 auxiliary files for assignments, files submitted by users and evaluation 
-results. For a description of the communication protocol used by the frontend 
-and workers, see the [Communication](#communication) chapter
+results. 
+
+For a description of the communication protocol used by the frontend 
+and workers, see the [Communication](#communication) chapter.
+
 
 ## Description
 
 The storage is implemented in Python, using the Flask web framework. This 
 particular implementation evolved from a simple mock fileserver we used in early
-stages of development.
+stages of development. It prooved to be very reliable, so we decided to keep fileserver
+as separate component instead of integrating this functionality into main API.
 
 ### Internal storage structure
 
 Fileserver stores its data in a configurable filesystem folder. This folder has 
 the following subfolders:
 
-- `./submissions/<id>` - folders that contain files submitted by users 
+- `./submissions/<id>` -- folders that contain files submitted by users 
   (student's solutions to assignments). `<id>` is an identifier received from 
   the ReCodEx API.
-- `./submission_archives/<id>.zip` - ZIP archives of all submissions. These are 
+- `./submission_archives/<id>.zip` -- ZIP archives of all submissions. These are 
   created automatically when a submission is uploaded. `<id>` is an identifier 
   of the corresponding submission.
-- `./tasks/<subkey>/<key>` - supplementary task files (e.g. test inputs and 
+- `./tasks/<subkey>/<key>` -- supplementary task files (e.g. test inputs and 
   outputs). `<key>` is a hash of the file content (sha-1 is used) and `<subkey>` 
   is its first letter (this is an attempt to prevent creating a flat directory 
   structure).
 
-## Installation
 
-To install and use the fileserver, it's necessary to have Python and Pip 
-installed.
+## Installation
 
-1. Clone this repository
-2. Install dependencies using `pip`
+To install and use the fileserver, it's necessary to have Python3 with `pip` package manager installed. It's needed to install the dependencies. From clonned repository run the following command:
 
 ```
-pip install -r requirements.txt
+$ pip install -r requirements.txt
 ```
 
+That's it. Fileserver doesn't need any special installation. It's possible to build and install _rpm_ package or install it without packaging the same way as monitor, but it's only optional. The installation would provide you with script `recodex-fileserver` in you `PATH`. No systemd unit files are provided, because of the configuration and usage of fileserver component is much different to our other Python parts.
+
+
 ## Configuration and usage
 
 There are several ways of running the ReCodEx fileserver. We'll cover two 
@@ -47,32 +51,62 @@ typical use cases.
 ### Running in development mode
 
 For simple development usage, it's possible to run the fileserver in the command 
-line:
+line. Allowed options are described below.
 
-~~~~~~~~~~~~~~~
-python3 fileserver.py runserver
-~~~~~~~~~~~~~~~
+```
+usage: fileserver.py [--directory WORKING_DIRECTORY]
+                     {runserver,shell} ...
+```
+
+- **runserver** argument starts the Flask development server (i.e. `app.run()`). As additional argument can be given a port number.
+- **shell** argument instructs Flask to run a Python shell inside application context.
 
-When run like this, the fileserver creates a temporary directory where it stores 
-all the files and which is deleted when it exits. It's possible to configure it 
-to use any other directory. Use the `--help` flag for a complete list of options 
-(such as the port where the server listens).
+Simple development server on port 9999 can be run as
 
-### Running with uWSGI and a web server
+```
+$ python3 fileserver.py runserver 9999
+```
 
-If you need features such as HTTP authentication or efficient serving of static 
+When run like this command, the fileserver creates a temporary directory where it stores all the files and which is deleted when it exits.
+
+
+### Running as WSGI script in a web server
+
+If you need features such as HTTP authentication (recommended) or efficient serving of static 
 files, it is recommended to run the app in a full-fledged web server (such as 
-Apache or Nginx) using WSGI. Following examples are simplified, use the `--help` 
-flag of the `mkconfig.py` script to see all available options.
+Apache or Nginx) using WSGI. Apache configuration can be generated by `mkconfig.py` script from the repository.
+
+```
+usage: mkconfig.py apache [-h] [--port PORT] --working-directory
+                          WORKING_DIRECTORY [--htpasswd HTPASSWD]
+                          [--user USER]
+```
+
+- **port** -- port where the fileserver should listen
+- **working_directory** -- directory where the files should be stored
+- **htpasswd** -- path to user file fot HTTP Basic Authentication
+- **user** -- user under which the server should be run
 
 ### Running using uWSGI
 
+Another option is to run fileserver as a standalone app via uWSGI service. Setup is also quite simple, configuration file can be also generated by `mkconfig.py` script.
+
 1. (Optional) Create a user for running the fileserver
 2. Make sure that your user can access your clone of the repository
-3. Run `python mkconfig/mkconfig.py uwsgi --port PORT --user YOUR_USER 
-   --working-directory DIR`
+3. Run `mkconfig.py` script.
+	```
+	usage: mkconfig.py uwsgi [-h] [--user USER] [--port PORT]
+	                         [--socket SOCKET]
+                             --working-directory WORKING_DIRECTORY
+	```
+
+	- **user** -- user under which the server should be run
+	- **port** -- port where the fileserver should listen
+	- **socket** -- path to UNIX socket where the fileserver should listen
+	- **working_directory** -- directory where the files should be stored
+	
 4. Save the configuration file generated by the script and run it with uWSGI, 
-   either directly or using systemd. This depends heavily on your distribution
+   either directly or using systemd. This depends heavily on your distribution.
 5. To integrate this with another web server, see the [uWSGI 
    documentation](http://uwsgi-docs.readthedocs.io/en/latest/WebServers.html)
 
@@ -81,3 +115,4 @@ necessary to convert the configuration file to XML and make sure that the
 python3 plugin is loaded instead of python. This plugin also uses Python 3.4, 
 even though the rest of the system uses Python 3.5 - make sure to install 
 dependencies for the correct version.
+