zen_engine/loader/
filesystem.rs

1use std::fs::File;
2use std::future::Future;
3use std::io::BufReader;
4use std::path::{Path, PathBuf};
5use std::pin::Pin;
6use std::sync::Arc;
7
8use serde::{Deserialize, Serialize};
9
10use crate::loader::{DecisionLoader, LoaderError, LoaderResponse};
11use crate::model::DecisionContent;
12
13/// Loads decisions based on filesystem root
14#[derive(Debug)]
15pub struct FilesystemLoader {
16    root: String,
17}
18
19#[derive(Serialize, Deserialize)]
20pub struct FilesystemLoaderOptions<R: Into<String>> {
21    pub root: R,
22}
23
24impl FilesystemLoader {
25    pub fn new<R>(options: FilesystemLoaderOptions<R>) -> Self
26    where
27        R: Into<String>,
28    {
29        Self {
30            root: options.root.into(),
31        }
32    }
33
34    fn key_to_path<K: AsRef<str>>(&self, key: K) -> PathBuf {
35        Path::new(&self.root).join(key.as_ref())
36    }
37
38    fn read_content<K: AsRef<str>>(&self, key: K) -> LoaderResponse {
39        let path = self.key_to_path(key.as_ref());
40        if !Path::exists(&path) {
41            return Err(LoaderError::NotFound(String::from(key.as_ref())));
42        }
43
44        let file = File::open(path).map_err(|e| LoaderError::Internal {
45            key: String::from(key.as_ref()),
46            source: e.into(),
47        })?;
48
49        let reader = BufReader::new(file);
50        let result: DecisionContent =
51            serde_json::from_reader(reader).map_err(|e| LoaderError::Internal {
52                key: String::from(key.as_ref()),
53                source: e.into(),
54            })?;
55
56        Ok(Arc::new(result))
57    }
58}
59
60impl DecisionLoader for FilesystemLoader {
61    fn load<'a>(
62        &'a self,
63        key: &'a str,
64    ) -> Pin<Box<dyn Future<Output = LoaderResponse> + 'a + Send>> {
65        Box::pin(async move { self.read_content(key) })
66    }
67
68    fn load_sync(&self, key: &str) -> Option<LoaderResponse> {
69        Some(self.read_content(key))
70    }
71
72    fn keys(&self) -> Option<Vec<Arc<str>>> {
73        let root = Path::new(&self.root);
74        let mut keys = Vec::new();
75        let mut stack = vec![root.to_path_buf()];
76        while let Some(dir) = stack.pop() {
77            let Ok(entries) = std::fs::read_dir(&dir) else {
78                continue;
79            };
80            for entry in entries.flatten() {
81                let path = entry.path();
82                if path.is_dir() {
83                    stack.push(path);
84                } else if path.extension().and_then(|e| e.to_str()) == Some("json") {
85                    let key = path.strip_prefix(root).ok().and_then(|rel| {
86                        rel.components()
87                            .map(|component| component.as_os_str().to_str())
88                            .collect::<Option<Vec<_>>>()
89                            .map(|segments| segments.join("/"))
90                    });
91                    if let Some(key) = key {
92                        keys.push(Arc::from(key));
93                    }
94                }
95            }
96        }
97        Some(keys)
98    }
99}
100
101#[cfg(test)]
102mod tests {
103    use super::*;
104
105    fn test_loader() -> FilesystemLoader {
106        let root = Path::new(env!("CARGO_MANIFEST_DIR"))
107            .parent()
108            .unwrap()
109            .parent()
110            .unwrap()
111            .join("test-data");
112        FilesystemLoader::new(FilesystemLoaderOptions {
113            root: root.to_string_lossy().to_string(),
114        })
115    }
116
117    #[tokio::test]
118    async fn load_and_load_sync_resolve_existing_key() {
119        let loader = test_loader();
120
121        assert!(loader.load("table.json").await.is_ok());
122        assert!(loader.load_sync("table.json").unwrap().is_ok());
123    }
124
125    #[tokio::test]
126    async fn load_reports_missing_key() {
127        let loader = test_loader();
128
129        assert!(loader.load("missing.json").await.is_err());
130        assert!(loader.load_sync("missing.json").unwrap().is_err());
131    }
132}
zen_engine/loader/filesystem.rs

zen_engine/loader/
filesystem.rs
