strop_workspace/
container.rs

1//! Container namespace identity (0037 DC1a): a running container on the
2//! local engine is its own filesystem namespace — paths inside it are
3//! never local paths. The engine is local-only in v1; a remote-engine
4//! field is earned with DC5, not reserved.
5
6/// A canonical container identity: the 64-hex id `docker inspect`
7/// reports. Names and prefixes resolve through inspect first; the checked
8/// constructor keeps a display label from ever becoming an identity.
9#[derive(Debug, Clone, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
10#[serde(try_from = "String", into = "String")]
11pub struct ContainerId(String);
12
13/// Why a container identity string was refused.
14#[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
15#[error("a container identity is the 64-hex inspect id, not a name or prefix")]
16pub struct ContainerIdError;
17
18impl ContainerId {
19    pub fn canonical(value: String) -> Result<Self, ContainerIdError> {
20        let valid = value.len() == 64
21            && value
22                .bytes()
23                .all(|b| b.is_ascii_digit() || (b'a'..=b'f').contains(&b));
24        if valid {
25            Ok(Self(value))
26        } else {
27            Err(ContainerIdError)
28        }
29    }
30
31    pub fn as_str(&self) -> &str {
32        &self.0
33    }
34}
35
36impl std::fmt::Display for ContainerId {
37    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
38        formatter.write_str(&self.0)
39    }
40}
41
42impl TryFrom<String> for ContainerId {
43    type Error = ContainerIdError;
44    fn try_from(value: String) -> Result<Self, Self::Error> {
45        Self::canonical(value)
46    }
47}
48impl From<ContainerId> for String {
49    fn from(value: ContainerId) -> Self {
50        value.0
51    }
52}
53
54#[cfg(test)]
55mod tests {
56    use super::*;
57
58    #[test]
59    fn canonical_ids_roundtrip_and_names_refuse() {
60        let id = ContainerId::canonical("a".repeat(64)).unwrap();
61        assert_eq!(id.as_str(), &"a".repeat(64));
62        assert!(ContainerId::canonical("name".into()).is_err());
63        assert!(
64            ContainerId::canonical("A".repeat(64)).is_err(),
65            "lowercase hex"
66        );
67        let json = serde_json::to_string(&id).unwrap();
68        assert_eq!(serde_json::from_str::<ContainerId>(&json).unwrap(), id);
69        assert!(serde_json::from_str::<ContainerId>("\"name\"").is_err());
70    }
71}
strop_workspace/container.rs

strop_workspace/
container.rs
