# aws-greengrass-nucleus-rust

[![crates.io page](https://img.shields.io/badge/crates.io-0.0.3-brightgreen)](https://crates.io/crates/aws-greengrass-nucleus)

aws greengrass nucleus in Rust programming language (unofficial)


## Motivation
---
> **What I cannot create, I do not understand.**
>
> **Know how to solve every problem that has been solved.**
>
>                                       ————  Richard Feynman 
>> *on his blackboard at the time of death in February 1988;*
>>

---

## Quickstart
1. cargo run -- --version
``` 
aws-greengrass-nucleus 0.0.3
```

2. cargo run -- --help
```
aws-greengrass-nucleus 0.0.3
aws greengrass nucleus in Rust (unofficial)

USAGE:
    aws-greengrass-nucleus [OPTIONS] --thing-name <THING_NAME>

OPTIONS:
        --aws-region <AWS_REGION>
            [default: ap-southeast-1]

        --component-default-user <COMPONENT_DEFAULT_USER>
            

        --deploy-dev-tools
        ...
```

3. cargo run -- --aws-region ap-southeast-1 --thing-name coreName  --component-default-user ggc_user:ggc_group --provision
```
same as original nucleus
```

## Nucleus
The Greengrass nucleus component (aws.greengrass.Nucleus) is a **mandatory** component and the **minimum** requirement to run the AWS IoT Greengrass Core software on a device. 

### a little bit of history

- [v1 preview in 2016/11](https://aws.amazon.com/about-aws/whats-new/2016/11/announcing-aws-greengrass-now-in-limited-preview/)
- [v1 release in 2017/06](https://aws.amazon.com/about-aws/whats-new/2017/06/aws-greengrass-is-now-generally-available/)
- [v2 release in 2020/12](https://www.youtube.com/watch?v=fBNG8OglRZQ)
- [v1 will dead on 2023/06](https://docs.aws.amazon.com/greengrass/v1/developerguide/what-is-gg.html)

### How big?
#### v1 (maybe golang?)
    - Minimum 128 MB disk space available for the AWS IoT Greengrass Core software. If you use the OTA update agent, the minimum is 400 MB.

    - Minimum 128 MB RAM allocated to the AWS IoT Greengrass Core software. With stream manager enabled, the minimum is 198 MB RAM.

#### v2 (open source in Java)
    - memory,
    The maximum amount of RAM (in kilobytes) that each component's processes can use on the core device.

### How v2 works?
[Greengrass v2 CLI](https://awscli.amazonaws.com/v2/documentation/api/2.1.30/reference/greengrassv2/index.html)

core-device:
- list-core-devices
- get-core-device
- delete-core-device

component:
- create-component-version
- describe-component
- delete-component
- get-component
- get-component-version-artifact
- list-component-versions
- list-components
- resolve-component-candidates

deployments:
- create-deployment
- list-deployments
- get-deployment
- cancel-deployment

misc:
- list-effective-deployments
- list-installed-components
- list-tags-for-resource
- tag-resource
- untag-resource

## How to

- open documentation:
> cargo doc --open

- Compile local packages and all of their dependencies:
> cargo b(uild)

- Release build:
> cargo b --release

- Cross-compile:
> rustup target list
> rustup target add <arch->
> cargo b --target <>

- Cross-compile for Raspberry:
> https://robamu.github.io/post/cross-compile-rust-rpi/


- Cross-compile for OpenWRT:
> https://blog.dend.ro/building-rust-for-routers/

- Fast check:
> cargo c(heck)

- Run:
> cargo run (-- your-args)

- Test:
> cargo test

- Documentation tests:
> https://doc.rust-lang.org/rustdoc/write-documentation/documentation-tests.html#documentation-tests

- Publish:
> cargo publish

## Design

see docs/design.md

## Use case
The following example shows how an AWS IoT Greengrass device interacts with the AWS IoT Greengrass cloud service and other AWS services in the AWS Cloud.
![example](https://docs.aws.amazon.com/greengrass/v2/developerguide/images/how-it-works.png)