snurr 0.12.0

Read BPMN 2.0 files and run the process flow
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# Snurr


[![Build Status](https://github.com/sajox/snurr/actions/workflows/rust.yml/badge.svg)](https://github.com/sajox/snurr/actions)

**Snurr** can run the process flow from a Business Process Model and Notation (BPMN) 2.0 file created by <https://demo.bpmn.io/new>.

- Add your own behavior with Rust code from a small API. The wiring is already setup from the file.
- Easy to update the BPMN diagram with new Task and Gateways without the need to refactor your old code.
- The BPMN file is the actual design. Forget outdated documentation.
- Scaffold the initial BPMN diagram so you don't have to do the boilerplate code.
- Contains no database.
- Single or multithreaded (opt in)

Read the [Snurr documentation](https://github.com/sajox/snurr/blob/main/docs/documentation.md) and explore the **tests** folder for more examples.

**_NOTE:_** To view or edit BPMN files in your project you can use the [BPMN Editor](https://github.com/bpmn-io/vs-code-bpmn-io) plugin in VS Code.   

![Tasks](https://github.com/sajox/snurr/blob/main/assets/images/vscode-plugin-bpmnio.png?raw=true)

## Example


BPMN diagram used in example.

![BPMN example](https://github.com/sajox/snurr/blob/main/assets/images/example.png?raw=true)

### Usage


```toml
[dependencies]
snurr = "0.12"
log = "0.4"
pretty_env_logger = "0.5"
```

```rust
use snurr::Process;

extern crate pretty_env_logger;

#[derive(Debug, Default)]

struct Counter {
    count: u32,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    pretty_env_logger::init();

    let bpmn = Process::<_, Counter>::new("examples/example.bpmn")?
        .task("Count 1", |input| {
            input.lock().unwrap().count += 1;
            None
        })
        .exclusive("equal to 3", |input| {
            if input.lock().unwrap().count == 3 {
                "YES"
            } else {
                "NO"
            }
            .into()
        })
        .build()?;

    let counter = bpmn.run(Counter::default())?;
    println!("Count: {}", counter.count);
    Ok(())
}
```

### Output


If RUST_LOG=info is set when running [example](#usage)

```
 INFO  snurr::process::engine > Start: Begin process
 INFO  snurr::process::engine > SequenceFlow: count
 INFO  snurr::process::engine > Task: Count 1
 INFO  snurr::process::engine > SequenceFlow: control
 INFO  snurr::process::engine > Exclusive: equal to 3
 INFO  snurr::process::engine > SequenceFlow: NO
 INFO  snurr::process::engine > Task: Count 1
 INFO  snurr::process::engine > SequenceFlow: control
 INFO  snurr::process::engine > Exclusive: equal to 3
 INFO  snurr::process::engine > SequenceFlow: NO
 INFO  snurr::process::engine > Task: Count 1
 INFO  snurr::process::engine > SequenceFlow: control
 INFO  snurr::process::engine > Exclusive: equal to 3
 INFO  snurr::process::engine > SequenceFlow: YES
 INFO  snurr::process::engine > End: End process
Count: 3
```

### Prepared sample


Run or copy the simple.rs in the examples folder

```
RUST_LOG=info cargo run --example simple
```