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_ARGS", input.args.join(" "))
36            .env("LOWFAT_EXIT_CODE", input.exit_code.to_string())
37            .spawn()
38            .with_context(|| format!("failed to spawn plugin: sh {entry}"))?;
39
40        if let Some(mut stdin) = child.stdin.take() {
41            let _ = stdin.write_all(input.raw.as_bytes());
42        }
43
44        let output = child.wait_with_output()?;
45        let text = String::from_utf8_lossy(&output.stdout).to_string();
46
47        Ok(FilterOutput {
48            passthrough: text.is_empty(),
49            text,
50        })
51    }
52}
53
54#[cfg(test)]
55mod tests {
56    use super::*;
57    use lowfat_core::level::Level;
58    use std::io::Write;
59
60    fn make_input(raw: &str) -> FilterInput {
61        FilterInput {
62            raw: raw.to_string(),
63            command: "test".to_string(),
64            subcommand: "sub".to_string(),
65            args: vec!["arg1".to_string()],
66            level: Level::Full,
67            head_limit: 40,
68            exit_code: 0,
69        }
70    }
71
72    fn make_filter(entry: &str, code: &str) -> ProcessFilter {
73        let dir = std::env::temp_dir().join(format!("lowfat-test-{}-{}", entry, std::process::id()));
74        std::fs::create_dir_all(&dir).unwrap();
75        let path = dir.join(entry);
76        let mut f = std::fs::File::create(&path).unwrap();
77        f.write_all(code.as_bytes()).unwrap();
78
79        ProcessFilter {
80            info: PluginInfo {
81                name: "test-plugin".into(),
82                version: "0.1.0".into(),
83                commands: vec!["test".into()],
84                subcommands: vec![],
85            },
86            entry: path,
87            base_dir: dir,
88        }
89    }
90
91    #[test]
92    fn shell_filter() {
93        let filter = make_filter("filter.sh", "#!/bin/sh\ngrep -v '^warning:'");
94        let input = make_input("ok line\nwarning: skip\nanother line");
95        let result = filter.filter(&input).unwrap();
96        assert_eq!(result.text.trim(), "ok line\nanother line");
97        assert!(!result.passthrough);
98    }
99
100    #[test]
101    fn shell_env_vars() {
102        let code = "#!/bin/sh\necho \"level=$LOWFAT_LEVEL\"\necho \"cmd=$LOWFAT_COMMAND\"\necho \"sub=$LOWFAT_SUBCOMMAND\"\necho \"args=$LOWFAT_ARGS\"\necho \"exit=$LOWFAT_EXIT_CODE\"";
103        let filter = make_filter("env.sh", code);
104        let input = make_input("ignored");
105        let result = filter.filter(&input).unwrap();
106        assert!(result.text.contains("level=full"));
107        assert!(result.text.contains("cmd=test"));
108        assert!(result.text.contains("sub=sub"));
109        assert!(result.text.contains("args=arg1"));
110        assert!(result.text.contains("exit=0"));
111    }
112
113    #[test]
114    fn empty_output_passthrough() {
115        let filter = make_filter("empty.sh", "#!/bin/sh\n# output nothing");
116        let input = make_input("some input");
117        let result = filter.filter(&input).unwrap();
118        assert!(result.passthrough);
119        assert!(result.text.is_empty());
120    }
121}
lowfat_runner/process.rs

lowfat_runner/
process.rs
