Googol

Googol is a well-simple program that outputs generations of Conway's Game of Life as GIF animation. The name is a lousy acronym which stands for Googol is yet another game of life. It was written in Golang, thus some gophers certainly will prefer Game of Life... err.. oh! in golang...

If you are hooked on Game of Life maybe you should like also check another implementation of mine of this game by using IA-32 assembly here.

How can I build it?

You need Golang installed. You can get it installed by accessing.

Being a Golang program, you can only use:

    you@somewhere:~/over/the/rainbow# go run googol.go [sub-command] [options]
    you@somewhere:~/over/the/rainbow# _

If you actually want to its binary, use:

    you@somewhere:~/over/the/rainbow# go build googol.go
    you@somewhere:~/over/the/rainbow# ./googol [sub-command] [options]
    you@somewhere:~/over/the/rainbow# _

If you want to install it, you will need to install Hefesto.

Once Hefesto well-installed and running. Do the following:

    you@somewhere:~/over/the/rainbow# mkdir temp-mess
    you@somewhere:~/over/the/rainbow/temp-mess# git clone https://github.com/rafael-santiago/helios
    you@somewhere:~/over/the/rainbow/temp-mess/helios# hefesto --install=go-toolset
    you@somewhere:~/over/the/rainbow/temp-mess/helios# cd ../..
    you@somewhere:~/over/the/rainbow# rm -rf temp-mess

Now your Hefesto copy knows how to build a Golang program. If you want to build the program by using Hefesto:

    you@somewhere:~/over/the/rainbow# hefesto
    you@somewhere:~/over/the/rainbow# _

In order to install Googol on your system:

    you@somewhere:~/over/the/rainbow# hefesto --install
    you@somewhere:~/over/the/rainbow# _

Uninstalling:

    you@somewhere:~/over/the/rainbow# hefesto --uninstall
    you@somewhere:~/over/the/rainbow# _

How can I create certificates for httpd mode?

I have automated it through a build task that you can use just by invoking:

    you@somewhere:~/over/the/rainbow# hefesto --make-certificate \
    > --server-key=my-httpd.key --server-crt=my-httpd.crt
    you@somewhere:~/over/the/rainbow# _

How can I play with it?

If you do not know what Game of Life is take a look at here.

Until now googol can be used in two ways. As a batch tool that can creates GIF images representing the game's generations or as a webserver with a web page where you can input game data and see its output.

Playing with it in batch mode

Use the sub-command gif:

    you@somewhere:~/over/the/rainbow# googol gif > big-blank.gif
    you@somewhere:~/over/the/rainbow# _

This is the shortest way of using the gif command. However, it will produce game generations that are nothing else that a big boredom. You need to define the initial game board state. The way of doing it is by passing a set of options in the form --<n>,<n>., where denotes the alive cell coordinates.

Let's suppose we want to define a blinker:

    you@somewhere:~/over/the/rainbow# googol gif --2,2. --2,3. --2,4. > blinker.gif
    you@somewhere:~/over/the/rainbow# _

The default output is stdout, but you can change it by passing --out=<file-path>:

    you@somewhere:~/over/the/rainbow# googol gif --2,2. --2,3. --2,4. \
    > --out=/usr/share/docs/gifs/conways-game-of-life-blinker.gif
    you@somewhere:~/over/the/rainbow# _

The GIF animation is not endless by default. In order to make it endless pass the option --endless.

    you@somewhere:~/over/the/rainbow# googol gif --2,2. --2,3. --2,4. \
    > --endless > blinker.gif
    you@somewhere:~/over/the/rainbow# _

This is the basic usage, anyway there are a bunch of other options accepted by gif sub-command. If you want to learn more get the gif's command guide in the following way:

    you@somewhere:~/over/the/rainbow# googol help gif
    you@somewhere:~/over/the/rainbow# _

The following command generates the acorn.gif pattern in Figure 1.

    you@somewhere:~/over/the/rainbow# googol gif \
    > --50,50. --51,52. --52,49. --52,50. --52,53. --52,54. --52,55. \
    > --board-width=100 --board-height=100 \
    > --cell-size-inpx=2 --delay=1 --gen-total=5206 \
    > --gif-width=200 --gif-height=200 --endless --out=acorn.gif
    you@somewhere:~/over/the/rainbow# _

Figure 1: Acorn pattern.

Playing with it in httpd mode

Use the sub-command httpd:

    you@somewhere:~/over/the/rainbow# googol httpd
    you@somewhere:~/over/the/rainbow# _

If you run the command above, a webserver at http://localhost:8080/googol will be created. Only you will be able to access it. If you want to other people accessing it you must to pass the interface address:

    you@somewhere:~/over/the/rainbow# googol httpd --addr=<your-ip-or-hostname>
    you@somewhere:~/over/the/rainbow# _

In order to set another port than 8080:

    you@somewhere:~/over/the/rainbow# googol httpd --addr=<your-ip-or-hostname> \
    > --port=101
    you@somewhere:~/over/the/rainbow# _

It is also possible to have a secure httpd by passing --https option flag, but in this case will be necessary to pass --server-crt and --server-key options, too. The --server-crt must point to a valid crt file and the --server-key must point to a valid private key file.

    you@somewhere:~/over/the/rainbow# googol httpd --addr=<your-ip-or-hostname> \
    > --port=101 --server-crt=etc/googol.crt --server-key=etc/googol.key --https
    you@somewhere:~/over/the/rainbow# _

In order to define a default alive cells set pass options in the same form that gif command expects (--<n>,<n>.).

If you want to change the (lousy) HTML form template, use the option --form-template:

you@somewhere:~/over/the/rainbow# googol httpd \
> --form-template=etc/poetry-in-html/your-utter-awesome-googol-template.html
you@somewhere:~/over/the/rainbow# _

Table 1 lists all available template actions.

Table 1: All available HTML template actions.

Action	Expands to
{{.Proto}}	http or https depending on --https option flag
{{.Addr}}	the server address
{{.Port}}	the server port
{{.InitialState}}	lists the set of initial alive cells (iterate over by using .range)
{{.BoardWidth}}	the board width
{{.BoardHeight}}	the board height
{{.GIFWidth}}	the GIF width
{{.GIFHeight}}	the GIF height
{{.Delay}}	the animation delay
{{.CellSizeInPx}}	the number of pixels per board cell
{{.GenTotal}}	the total of game generations
{{.BkColor}}	a HTML select field which lists all available background colors
{{.FgColor}}	a HTML select field which lists all available foreground colors
{{.Endless}}	the current state of '--endless' flag (for the current game instance)
{{.Error}}	an error message when occurred one
{{.GIFData}}	GIF image encoded in radix/base-64

The best way of understanding how to deal with those template actions is by reading etc/template.html.

The sub-command httpd also accepts a bunch of other commands that you can learn more by running its command guide:

    you@somewhere:~/over/the/rainbow# googol help httpd
    you@somewhere:~/over/the/rainbow# _

In Figure 2 you can see the Googol's default HTML interface.

Figure 2: Default HTML interface.