gates

A gate service submission for the LLJam 0001

Dependencies

• make
• go 1.17
• docker

Building

Docker

The tool can be built and run entirely via docker using the following command.

$> docker build -t ncatelli/gates .

Locally

The tool can also be built locally via make

$> make build

Testing

Tests can be run using the built in go testing library and a convenient wrapper to test all subpackages has been provided below.

Locally

Local tests default to running tests on all subpackages along with coverage tests. Tests can be run with the following make command.

$> make test

Configuration

Services

The service can be configured via the following subcommands and flags:

Subcommands

Gates

The following subcommands are valid gates

• not
• and
• or
• xor
• nand
• nor

Of these, the following flags can be set. Be aware that the output-addr determines if gate output is sent to stdout or to another http service.

• listen-addr string The server address gates binds to. (default "127.0.0.1:8080")
• output-addrs string An optional comma-separated list of URLs for the http outputter to send a computed output to. If empty the stdout outputter is used.

Usage

Example

docker-compose.yaml

A minimal compose environment that showcases a few gates is available in the repo. This can be started by running:

$ docker-compose up -d

This example exposes a few gates that are wired up to eachother, notably a not, or gate which feeds their output into an and gate that outputs its result. Addtionally a xor gate is setup as a standalone gate with it's output wired to stdout.

These be sent signals using the curl template, replacing the values inbetween the <> with the the value i will describe below.:

curl -X POST -sD - -d '{"state": <boolean>, "tick": <unsigned integer>}' <gate host>:8080/input/<input id>

Post Body

The post body is a json object with two fields

• state: stores a boolean value representing if the input is a 0 or 1
• tick: an unsigned integer representing a cycle count.

It's worth noting that ticks do not have to be in order. Gates will store inputs for a given tick regardless of the order it is received.

URL

Each gate has a unique url, and by default listens on port 8080.

Each gate exposes it's input via a unique path, where the inputs are ordered by incrementing single lowercase characters starting from a.

For example, the url for the solitary input of a not gate at the address not_gate:8080 would be http://not_gate:8080/input/a. The urls for the two inputs of an and gate at the address and_gate:8080 would be http://and_gate:8080/input/a and http://and_gate:8080/input/b etc...

Putting it all together

Below shows a curl request to the not gate, that sets the input for the first tick to false. Causing a true output to the and_gate service's a input.

$ curl -X POST -sD - -d '{"state": false, "tick": 0}' localhost:8080/input/a
HTTP/1.1 202 Accepted
Date: Sun, 19 Jun 2022 16:02:46 GMT
Content-Length: 0

Below shows a subsequent two curl requests to the or gate, that set the input for the first tick both to true. Causing a true output to the and_gate service's b input.

$ curl -X POST -sD - -d '{"state": true, "tick": 0}' localhost:8081/input/a
HTTP/1.1 202 Accepted
Date: Sun, 19 Jun 2022 16:01:54 GMT
Content-Length: 0

$ curl -X POST -sD - -d '{"state": true, "tick": 0}' localhost:8081/input/b
HTTP/1.1 202 Accepted
Date: Sun, 19 Jun 2022 16:02:05 GMT
Content-Length: 0

When both inputs for tick 0 are received, the and_gate service outputs. This service is configured to use the stdout outputter via the OUTPUT_TYPE env var in the docker-compose.yaml file. Thus the results can be seen in the service's log to be set to the expected value of true.

$ docker-compose logs and_gate                                              
Attaching to gates_and_gate_1
and_gate_1  | 2022/06/19 16:04:58 Starting server on 0.0.0.0:8080
and_gate_1  | 2022/06/19 16:04:58 Configured as and gate
and_gate_1  | 2022/06/19 16:05:14 tick: 0, state: true

Finally, this can all be cleaned up with the following:

docker-compose down -v --rmi local

docker-compose-half-adder.yaml

This implementation provides a half-adder along with a single inputter service that loops continuously, sending a true input.