Merge pull request #1 from dimacurrentai/mermaid

Mermaid sequence diagram generation.

Author: dkorolev

step03_mermaid/.gitignore

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+.mermaid.md

step03_mermaid/Dockerfile

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+# Build the binaries statically, and then run them from a separate container.
+FROM alpine AS build
+
+# Intentionally not installing `cargo`, etc. But it does need `clang`.
+RUN apk add rustup clang musl
+
+# Init local rust via `rustup`, including static targets builder.
+RUN rustup-init -y -t x86_64-unknown-linux-musl --no-modify-path 
+RUN mv /root/.cargo/bin/* /usr/local/bin/
+
+# Build the project.
+COPY ./code /code
+WORKDIR /code
+RUN cargo build --release --target x86_64-unknown-linux-musl
+
+# Prepare the static binary.
+RUN cp ./target/x86_64-unknown-linux-musl/release/mermaid /
+
+# The resulting container with the static binary only.
+FROM scratch
+COPY --from=build /mermaid /mermaid
+ENTRYPOINT ["/mermaid"]

step03_mermaid/code/Cargo.toml

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+[package]
+name = "mermaid"
+edition = "2024"

step03_mermaid/code/src/main.rs

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+mod mermaid {
+  struct Data {
+    contents: String,
+    i: i32,
+  }
+  pub struct Canvas {
+    instance: std::cell::RefCell<Data>,
+  }
+  pub struct Participant<'a> {
+    canvas: &'a Canvas,
+    i: i32,
+    _name: String,
+  }
+  impl Canvas {
+    pub fn new() -> Self {
+      Self {
+        instance: std::cell::RefCell::new(Data {
+          contents: "sequenceDiagram\n    create participant I0 as root\n    autonumber\n".to_string(),
+          i: 0,
+        }),
+      }
+    }
+    pub fn new_participant<S: AsRef<str>>(&self, s: S) -> Participant {
+      let mut data = self.instance.borrow_mut();
+      let curr_i = {
+        let i: &mut i32 = &mut data.i;
+        *i = *i + 1;
+        *i
+      };
+      Canvas::append_into(
+        data,
+        &format!("    create participant I{} as {}\n    I0-->>I{}: create\n", curr_i, s.as_ref(), curr_i),
+      );
+      Participant { canvas: self, i: curr_i, _name: String::from(s.as_ref()) }
+    }
+    fn append_into<S: AsRef<str>>(mut data: std::cell::RefMut<Data>, s: S) {
+      data.contents.push_str(s.as_ref());
+    }
+    fn append<S: AsRef<str>>(&self, s: S) {
+      Canvas::append_into(self.instance.borrow_mut(), s.as_ref());
+    }
+    pub fn output<F>(&self, f: F)
+    where
+      F: FnOnce(&String),
+    {
+      f(&self.instance.borrow().contents)
+    }
+  }
+  impl<'a> Participant<'a> {
+    pub fn add_arrow_to(&self, rhs: &Participant, text: &str) {
+      self.canvas.append(format!("    I{}->>I{}: {}\n", self.i, rhs.i, text));
+    }
+  }
+  impl<'a> Drop for Participant<'a> {
+    fn drop(&mut self) {
+      self.canvas.append(format!("    destroy I{}\n    I{}-->>I0: destroy\n", self.i, self.i));
+    }
+  }
+}
+
+use mermaid::Canvas;
+//use medmaid::Participant;
+
+fn main() {
+  let canvas = Canvas::new();
+
+  {
+    canvas.new_participant("foo");
+  }
+  {
+    let bar = canvas.new_participant("bar");
+    {
+      let baz = canvas.new_participant("baz");
+      bar.add_arrow_to(&baz, "Hello!");
+    }
+  }
+
+  {
+    let meh = canvas.new_participant("meh");
+    {
+      let blah = canvas.new_participant("blah");
+      blah.add_arrow_to(&meh, "Whoa!");
+    }
+  }
+
+  canvas.output(|s| println!("{}", s));
+}

step03_mermaid/mermaid.md

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+```mermaid
+sequenceDiagram
+    create participant I0 as root
+    autonumber
+    create participant I1 as foo
+    I0-->>I1: create
+    destroy I1
+    I1-->>I0: destroy
+    create participant I2 as bar
+    I0-->>I2: create
+    create participant I3 as baz
+    I0-->>I3: create
+    I2->>I3: Hello!
+    destroy I3
+    I3-->>I0: destroy
+    destroy I2
+    I2-->>I0: destroy
+    create participant I4 as meh
+    I0-->>I4: create
+    create participant I5 as blah
+    I0-->>I5: create
+    I5->>I4: Whoa!
+    destroy I5
+    I5-->>I0: destroy
+    destroy I4
+    I4-->>I0: destroy
+
+```

step03_mermaid/run.sh

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+#!/bin/bash
+
+set -e
+
+docker build . -t demo
+
+echo '```mermaid' >.mermaid.md
+docker run --rm -t demo | tee >>.mermaid.md
+echo '```' >>.mermaid.md
+
+# TODO(dkorolev): Fail with a nicer message, and add a git hook.
+diff mermaid.md .mermaid.md || echo 'Your `mermaid.md` file is not up to date.'