#+title: Rust Quickstart
#+date:[2023-11-19 Sun]
#+author: HaQadosch
#+startup: indent
#+note: based on https://developer.fermyon.com/spin/v2/quickstart
#+link: article https://developer.fermyon.com/spin/v2/quickstart

* Org shortcuts
** Feetnotes[fn:1]
- create footnote :: ~C-c C-x f~
- jump to the footnote ref :: ~C-c C-c~
* Instaling Rust
Looking at the [[https://www.rust-lang.org/learn/get-started][get-started doc]],
let's use ~rustup~
#+description: installing rust and libs using rustup
#+name: install rustup
#+begin_src shell
  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
#+end_src

Checking if the install went ok
#+description: running version and upgrade to confirm install is ok
#+name: confirm install
#+begin_src shell
  rustup --version
  rustup upgrade
#+end_src

#+RESULTS: confirm install
: rustup 1.26.0 (5af9b9484 2023-04-05)
: info: This is the version for the rustup toolchain manager, not the rustc compiler.
: info: The currently active `rustc` version is `rustc 1.74.0 (79e9716c9 2023-11-13)`
: info: syncing channel updates for 'stable-x86_64-unknown-linux-gnu'
: info: checking for self-update
:
:   stable-x86_64-unknown-linux-gnu unchanged - rustc 1.74.0 (79e9716c9 2023-11-13)
:
: info: cleaning up downloads & tmp directories


Ensure cargo, the package manager is also installed
#+name: confirm cargo installed
#+begin_src shell
  cargo --version
#+end_src

#+RESULTS: confirm cargo installed
: cargo 1.74.0 (ecb9851af 2023-10-18)
** Rust mode for emacs
Woohoo https://github.com/rust-lang/rust-mode
* Install Spin
This has been done already in a previous tut.
#+name: check install spin
#+begin_src shell
  spin -V
#+end_src

#+RESULTS: check install spin
: spin 2.0.1 (1d72f1c 2023-11-10)
* Install Templates for Rust
This has also been done in a previous tut.
#+name: check install templates
#+begin_src shell
  spin template list
#+end_src

#+RESULTS: check install templates
: +------------------------------------------------------------------------+
: | Name                Description                                        |
: +========================================================================+
: | http-c              HTTP request handler using C and the Zig toolchain |
: | http-empty          HTTP application with no components                |
: | http-go             HTTP request handler using (Tiny)Go                |
: | http-grain          HTTP request handler using Grain                   |
: | http-js             HTTP request handler using Javascript              |
: | http-php            HTTP request handler using PHP                     |
: | http-rust           HTTP request handler using Rust                    |
: | http-swift          HTTP request handler using SwiftWasm               |
: | http-ts             HTTP request handler using Typescript              |
: | http-zig            HTTP request handler using Zig                     |
: | redirect            Redirects a HTTP route                             |
: | redis-go            Redis message handler using (Tiny)Go               |
: | redis-rust          Redis message handler using Rust                   |
: | static-fileserver   Serves static files from an asset directory        |
: +------------------------------------------------------------------------+
* Installing Wasm
We need additional tools to support Wasm.
#+description: adding extra tools
#+name: add wasm
#+begin_src shell
  rustup target add wasm32-wasi
#+end_src

#+RESULTS: add wasm
: info: downloading component 'rust-std' for 'wasm32-wasi'
: info: installing component 'rust-std' for 'wasm32-wasi'
:  17.7 MiB /  17.7 MiB (100 %)  13.8 MiB/s in  1s ETA:  0s
* Create the first application
We use ~spin new~ and select the rust template ~http-rust~
#+name: spin new http-rust
#+begin_src shell
  spin new -t http-rust qstart
#+end_src

#+RESULTS: spin new http-rust
: Description []: a quick hello world
: Description: a quick hello world
: HTTP path [/...]:
: HTTP path: /...

#+description: check the folder structure for Rust app
#+name: tree qstart
#+begin_src shell
  tree qstart/
#+end_src

#+RESULTS: tree qstart
: qstart/
: ├── Cargo.toml
: ├── spin.toml
: └── src
:     └── lib.rs
:
: 2 directories, 3 files

The manifest file is =spin.toml=
#+begin_src toml
  spin_manifest_version = 2

  [application]
  name = "qstart"
  version = "0.1.0"
  authors = ["HaQadosch <redacted>"]
  description = "a quick hello world"

  [[trigger.http]]
  route = "/..."
  component = "qstart"

  [component.qstart]
  source = "target/wasm32-wasi/release/qstart.wasm"
  allowed_outbound_hosts = []
  [component.qstart.build]
  command = "cargo build --target wasm32-wasi --release"
  watch = ["src/**/*.rs", "Cargo.toml"]
#+end_src
* Modifying the code
We change the =qstar/lib.rs= file to display the =hello world= message.
#+description: line change for message
#+name: lib.rs diff
#+begin_src shell
  git diff
#+end_src

#+RESULTS: lib.rs diff
: diff --git a/qstart/src/lib.rs b/qstart/src/lib.rs
: index f3051ef..a51e027 100644
: --- a/qstart/src/lib.rs
: +++ b/qstart/src/lib.rs
: @@ -8,5 +8,5 @@ fn handle_qstart(req: Request) -> anyhow::Result<impl IntoResponse> {
:      Ok(http::Response::builder()
:          .status(200)
:          .header("content-type", "text/plain")
: -        .body("Hello, Fermyon")?)
: +        .body("Hello, World!")?)
:  }
* Building the app
In the ~qstart/~ folder
#+begin_src shell
  cd qstart/
  spin build
#+end_src

#+RESULTS:
: Building component qstart with `cargo build --target wasm32-wasi --release`
:     Finished release [optimized] target(s) in 0.17s
: Finished building all Spin components
* Running the app
We could have done ~spin build --up~ to autostart the app once the build has
been done.
#+description: running the app once build is finished
#+name: spin up the app
#+begin_src shell
  cd qstart/
  spin up
#+end_src

#+RESULTS: spin up the app
: Logging component stdio to ".spin/logs/"
:
: Serving http://127.0.0.1:3000
: Available Routes:
:   qstart: http://127.0.0.1:3000 (wildcard)
: 2023-11-19T18:38:54.648503Z ERROR spin_trigger::cli: Trigger executor failed
: Error: Unable to listen on 127.0.0.1:3000
:
: Caused by:
:      Address already in use (os error 98)

In this case we have another app running in the same port. Let's see which one.
#+name: lsof
#+begin_src shell
  lsof -i tcp:3000
#+end_src

#+RESULTS: lsof
: COMMAND     PID      USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME
: forgejo 1531870 haqadosch    7u  IPv6 8599019      0t0  TCP *:3000 (LISTEN)

So we kill that one and restart the ~spin up~.
#+name: spin up again
#+begin_src shell
  kill -9 1531870
  cd qstart/
  spin up
#+end_src

#+RESULTS: spin up again
: Logging component stdio to ".spin/logs/"
:
: Serving http://127.0.0.1:3000
: Available Routes:
:   qstart: http://127.0.0.1:3000 (wildcard)
* Try the app
We can display the page in your favourite browser or confirm with ~curl~
#+name: curl
#+begin_src shell
  curl -i localhost:3000
#+end_src

#+RESULTS: curl
: HTTP/1.1 200 OK
: content-type: text/plain
: transfer-encoding: chunked
: date: Sun, 19 Nov 2023 19:01:02 GMT
:
: Hello, World!