csb 0.2.0

Sandboxed Claude Code on Apple container
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136

pub(crate) const DEFAULT_IMAGE: &str = "claude-box";
pub(crate) const DEFAULT_MEMORY: &str = "6g";

pub(crate) struct Config {
    pub image: String,
    pub memory: String,
    /// True when `CSB_IMAGE` named the image. csb only rebuilds or warns about
    /// images it owns; a user-supplied one is theirs.
    pub image_is_custom: bool,
    /// Ready-to-pass `KEY=value` pairs for `container run -e`.
    pub env: Vec<String>,
}

impl Config {
    pub fn from_env() -> Self {
        Self::from_lookup(|key| std::env::var(key).ok())
    }

    /// Env lookup is injected so tests don't mutate process-global state — two
    /// tests doing `set_var` in parallel race, and `set_var` is `unsafe` from
    /// edition 2024 onward.
    pub fn from_lookup(lookup: impl Fn(&str) -> Option<String>) -> Self {
        let image = value(&lookup, "CSB_IMAGE", DEFAULT_IMAGE);
        Self {
            image_is_custom: image != DEFAULT_IMAGE,
            image,
            memory: value(&lookup, "CSB_MEMORY", DEFAULT_MEMORY),
            env: env_pairs(&lookup, "CSB_ENV"),
        }
    }
}

/// An empty or whitespace-only override is a mistake (`export CSB_MEMORY=`), not a
/// request to pass `-m ""` to `container`.
fn value(lookup: &impl Fn(&str) -> Option<String>, key: &str, default: &str) -> String {
    lookup(key)
        .map(|v| v.trim().to_string())
        .filter(|v| !v.is_empty())
        .unwrap_or_else(|| default.to_string())
}

/// `CSB_ENV` is a comma-separated list. `NAME=value` passes through literally;
/// a bare `NAME` forwards that variable's value from the host, and is dropped
/// when the host doesn't have it set.
fn env_pairs(lookup: &impl Fn(&str) -> Option<String>, key: &str) -> Vec<String> {
    let Some(raw) = lookup(key) else {
        return Vec::new();
    };

    raw.split(',')
        .map(str::trim)
        .filter(|entry| !entry.is_empty())
        .filter_map(|entry| match entry.split_once('=') {
            Some(_) => Some(entry.to_string()),
            None => lookup(entry).map(|v| format!("{entry}={v}")),
        })
        .collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    fn lookup(pairs: &'static [(&'static str, &'static str)]) -> impl Fn(&str) -> Option<String> {
        move |key| {
            pairs
                .iter()
                .find(|(k, _)| *k == key)
                .map(|(_, v)| v.to_string())
        }
    }

    #[test]
    fn config_should_use_defaults_when_env_vars_missing() {
        let config = Config::from_lookup(lookup(&[]));
        assert_eq!(config.image, "claude-box");
        assert_eq!(config.memory, "6g");
        assert!(!config.image_is_custom);
        assert!(config.env.is_empty());
    }

    #[test]
    fn config_should_read_custom_env_vars() {
        let config =
            Config::from_lookup(lookup(&[("CSB_IMAGE", "my-image"), ("CSB_MEMORY", "8g")]));
        assert_eq!(config.image, "my-image");
        assert_eq!(config.memory, "8g");
        assert!(config.image_is_custom);
    }

    #[test]
    fn config_should_not_treat_the_default_image_name_as_custom() {
        let config = Config::from_lookup(lookup(&[("CSB_IMAGE", "claude-box")]));
        assert!(!config.image_is_custom);
    }

    #[test]
    fn config_should_fall_back_when_env_vars_are_empty_or_whitespace() {
        let config = Config::from_lookup(lookup(&[("CSB_IMAGE", ""), ("CSB_MEMORY", "   ")]));
        assert_eq!(config.image, "claude-box");
        assert_eq!(config.memory, "6g");
    }

    #[test]
    fn config_should_trim_surrounding_whitespace() {
        let config = Config::from_lookup(lookup(&[("CSB_MEMORY", " 8g ")]));
        assert_eq!(config.memory, "8g");
    }

    #[test]
    fn env_should_pass_explicit_pairs_through() {
        let config = Config::from_lookup(lookup(&[(
            "CSB_ENV",
            "CONTEXT_MODE_DIR=/workspace/.context-mode, RTK_QUIET=1",
        )]));
        assert_eq!(
            config.env,
            vec!["CONTEXT_MODE_DIR=/workspace/.context-mode", "RTK_QUIET=1"]
        );
    }

    #[test]
    fn env_should_forward_bare_names_from_the_host() {
        let config = Config::from_lookup(lookup(&[
            ("CSB_ENV", "GH_TOKEN,MISSING_ONE"),
            ("GH_TOKEN", "secret"),
        ]));
        assert_eq!(config.env, vec!["GH_TOKEN=secret"]);
    }

    #[test]
    fn env_should_ignore_empty_entries() {
        let config = Config::from_lookup(lookup(&[("CSB_ENV", " , A=1 ,, ")]));
        assert_eq!(config.env, vec!["A=1"]);
    }
}