lowfat_runner/
process.rs

1use anyhow::{Context, Result};
2use lowfat_plugin::plugin::{FilterInput, FilterOutput, FilterPlugin, PluginInfo};
3use lowfat_plugin::security;
4use std::io::Write;
5use std::path::PathBuf;
6use std::process::{Command, Stdio};
7
8/// Runs a shell plugin as an external process via stdin/stdout.
9pub struct ProcessFilter {
10    pub info: PluginInfo,
11    pub entry: PathBuf,
12    pub base_dir: PathBuf,
13}
14
15impl FilterPlugin for ProcessFilter {
16    fn info(&self) -> PluginInfo {
17        self.info.clone()
18    }
19
20    fn filter(&self, input: &FilterInput) -> Result<FilterOutput> {
21        let entry = self.entry.to_string_lossy().to_string();
22        let safe_env = security::sanitized_env();
23
24        let mut child = Command::new("sh")
25            .arg(&entry)
26            .current_dir(&self.base_dir)
27            .stdin(Stdio::piped())
28            .stdout(Stdio::piped())
29            .stderr(Stdio::piped())
30            .env_clear()
31            .envs(safe_env)
32            .env("LOWFAT_LEVEL", input.level.to_string())
33            .env("LOWFAT_COMMAND", &input.command)
34            .env("LOWFAT_SUBCOMMAND", &input.subcommand)
35            .env("LOWFAT_EXIT_CODE", input.exit_code.to_string())
36            .spawn()
37            .with_context(|| format!("failed to spawn plugin: sh {entry}"))?;
38
39        if let Some(mut stdin) = child.stdin.take() {
40            let _ = stdin.write_all(input.raw.as_bytes());
41        }
42
43        let output = child.wait_with_output()?;
44        let text = String::from_utf8_lossy(&output.stdout).to_string();
45
46        Ok(FilterOutput {
47            passthrough: text.is_empty(),
48            text,
49        })
50    }
51}
52
53#[cfg(test)]
54mod tests {
55    use super::*;
56    use lowfat_core::level::Level;
57    use std::io::Write;
58
59    fn make_input(raw: &str) -> FilterInput {
60        FilterInput {
61            raw: raw.to_string(),
62            command: "test".to_string(),
63            subcommand: "sub".to_string(),
64            args: vec!["arg1".to_string()],
65            level: Level::Full,
66            head_limit: 40,
67            exit_code: 0,
68        }
69    }
70
71    fn make_filter(entry: &str, code: &str) -> ProcessFilter {
72        let dir = std::env::temp_dir().join(format!("lowfat-test-{}-{}", entry, std::process::id()));
73        std::fs::create_dir_all(&dir).unwrap();
74        let path = dir.join(entry);
75        let mut f = std::fs::File::create(&path).unwrap();
76        f.write_all(code.as_bytes()).unwrap();
77
78        ProcessFilter {
79            info: PluginInfo {
80                name: "test-plugin".into(),
81                version: "0.1.0".into(),
82                commands: vec!["test".into()],
83                subcommands: vec![],
84            },
85            entry: path,
86            base_dir: dir,
87        }
88    }
89
90    #[test]
91    fn shell_filter() {
92        let filter = make_filter("filter.sh", "#!/bin/sh\ngrep -v '^warning:'");
93        let input = make_input("ok line\nwarning: skip\nanother line");
94        let result = filter.filter(&input).unwrap();
95        assert_eq!(result.text.trim(), "ok line\nanother line");
96        assert!(!result.passthrough);
97    }
98
99    #[test]
100    fn shell_env_vars() {
101        let code = "#!/bin/sh\necho \"level=$LOWFAT_LEVEL\"\necho \"cmd=$LOWFAT_COMMAND\"\necho \"sub=$LOWFAT_SUBCOMMAND\"\necho \"exit=$LOWFAT_EXIT_CODE\"";
102        let filter = make_filter("env.sh", code);
103        let input = make_input("ignored");
104        let result = filter.filter(&input).unwrap();
105        assert!(result.text.contains("level=full"));
106        assert!(result.text.contains("cmd=test"));
107        assert!(result.text.contains("sub=sub"));
108        assert!(result.text.contains("exit=0"));
109    }
110
111    #[test]
112    fn empty_output_passthrough() {
113        let filter = make_filter("empty.sh", "#!/bin/sh\n# output nothing");
114        let input = make_input("some input");
115        let result = filter.filter(&input).unwrap();
116        assert!(result.passthrough);
117        assert!(result.text.is_empty());
118    }
119}
lowfat_runner/process.rs

lowfat_runner/
process.rs
