ruvnet/RuView · error · anyhow::Error

cannot read {path}: {e}

Error message

cannot read {path}: {e}

What it means

In the multistatic loop, each bank path extracted from `N:path` is read with `std::fs::read_to_string`, and any OS error is surfaced verbatim: ENOENT (missing file), EACCES (no read permission), EISDIR (a directory was passed), or 'stream did not contain valid UTF-8' for binary content. The file must be the plain-text JSON `SpecialistBank` serialization produced by the training/enroll tooling.

Source

Thrown at v2/crates/wifi-densepose-cli/src/room.rs:419

    }
    Ok(())
}

/// Multistatic `room-watch`: fuse several co-located nodes (ADR-029/151).
async fn room_watch_multi(args: RoomWatchArgs) -> Result<()> {
    use std::collections::{BTreeMap, VecDeque};

    let mut mix = MultiNodeMixture::new();
    let mut node_ids: Vec<u8> = Vec::new();
    for spec in &args.node_bank {
        let (id_s, path) = spec
            .split_once(':')
            .ok_or_else(|| anyhow::anyhow!("--node-bank must be N:path (got {spec:?})"))?;
        let id: u8 = id_s
            .parse()
            .map_err(|_| anyhow::anyhow!("bad node id in {spec:?}"))?;
        let raw = std::fs::read_to_string(path)
            .map_err(|e| anyhow::anyhow!("cannot read {path}: {e}"))?;
        let bank = SpecialistBank::from_json(&raw).map_err(|e| anyhow::anyhow!("{e}"))?;
        let baseline = bank.baseline_id.clone();
        mix.add_node(id, bank, baseline);
        node_ids.push(id);
    }
    eprintln!("[room-watch] multistatic over nodes {node_ids:?}");

    let addr = format!("{}:{}", args.bind, args.udp_port);
    let socket = UdpSocket::bind(&addr)
        .await
        .map_err(|e| anyhow::anyhow!("cannot bind {addr}: {e}"))?;
    eprintln!("[room-watch] fusing on udp://{addr} (window={} frames)", args.window);

    let mut buf = vec![0u8; RECV_BUF];
    let mut wins: BTreeMap<u8, VecDeque<f32>> = BTreeMap::new();
    let start = Instant::now();
    let mut last_print = Instant::now();

View on GitHub (pinned to 4685618388)

Solutions

1. Pass an absolute path: `--node-bank 1:/home/op/banks/node1.json`.
2. Verify the file is readable plain JSON: `test -r <path> && head -c1 <path>` should print `{`.
3. Fix permissions (`chmod +r`) or ownership if the error text says `Permission denied`.

Example fix

# before (launched by systemd, CWD=/)
room-watch --node-bank 1:node1.json
# after
room-watch --node-bank 1:/opt/ruview/banks/node1.json

fn bank_loadable(path: &str) -> bool {
    let p = std::path::Path::new(path);
    p.is_file()
        && std::fs::metadata(p).map(|m| !m.permissions().readonly()).unwrap_or(false)
        && std::fs::read_to_string(p).map(|s| s.trim_start().starts_with('{')).unwrap_or(false)
}

Err(e) => {
    if let Some(io) = e.downcast_ref::<std::io::Error>() {
        match io.kind() {
            std::io::ErrorKind::NotFound => eprintln!("bank file missing: check path/CWD"),
            std::io::ErrorKind::PermissionDenied => eprintln!("bank unreadable: chmod +r"),
            _ => eprintln!("bank read failed: {io}"),
        }
    }
}

When it happens

Trigger: Running the CLI from a different working directory than the bank's relative path; passing a directory as the path; a gzipped or otherwise binary bank file; unreadable ownership after an scp as root.

Common situations: Relative paths breaking when launched by systemd or a script whose CWD is `/`; files transferred with wrong ownership; trailing newline/whitespace injected into the path by shell variables.

Related errors

• cannot write {output}: {e}
• cannot read baseline {path}: {e} — run `calibrate` first
• cannot write {}: {e}
• cannot read {}: {e} — run `enroll` first
• cannot read geometry {path}: {e}

AI-assisted analysis of ruvnet/RuView@4685618388 (2026-08-16). Data as JSON: /api/errors/4519a46f413e3066. Report an issue: GitHub.