nikivdev/code · error

--follow requires specifying --server <name>

Error message

--follow requires specifying --server <name>

What it means

The logs command refuses to run in --follow mode without naming a server, because following requires a specific log stream to attach to; there is no defined behavior for following all servers. It is a usage-validation error thrown at the very start of `run` before any network activity.

Source

Thrown at src/logs.rs:17

use std::{
    io::{BufRead, BufReader},
    thread,
    time::Duration,
};

use anyhow::{Context, Result, bail};
use reqwest::blocking::Client;

use crate::{
    cli::LogsOpts,
    servers::{LogLine, LogStream, ServerSnapshot},
};

pub fn run(opts: LogsOpts) -> Result<()> {
    if opts.follow && opts.server.is_none() {
        bail!("--follow requires specifying --server <name>");
    }

    let base_url = format!("http://{}:{}", opts.host, opts.port);
    let use_color = !opts.no_color;
    let client = Client::builder()
        .timeout(std::time::Duration::from_secs(5))
        .build()
        .context("failed to build HTTP client")?;

    if let Some(server) = opts.server.as_deref() {
        if opts.follow {
            stream_server_logs(server, opts.host, opts.port, use_color)?;
        } else {
            let logs = fetch_logs(&client, &base_url, server, opts.limit)?;
            print_logs(&logs, use_color);
        }
        return Ok(());
    }

View on GitHub (pinned to a747e741ae)

Solutions

1. Pass the server name: `flow logs --follow --server <name>`.
2. Run `flow servers` (or equivalent list command) to see available server names first.
3. If you just want a one-shot dump of all logs, drop `--follow`.

Example fix

// before
flow logs --follow
// after
flow logs --follow --server my-server

if opts.follow && opts.server.is_none() {
    eprintln!("--follow requires --server <name>");
    std::process::exit(2);
}

fn follow_target_valid(opts: &LogsOpts) -> bool {
    !opts.follow || opts.server.as_deref().map(|s| !s.is_empty()).unwrap_or(false)
}

match logs::run(opts) {
    Err(e) if e.to_string().contains("--follow requires") => {
        eprintln!("Usage: flow logs --follow --server <name>");
        std::process::exit(2);
    }
    other => other?,
}

When it happens

Trigger: Invoking `flow logs --follow` (or setting LogsOpts.follow = true) while leaving LogsOpts.server as None.

Common situations: Typing the follow flag but forgetting the server name; scripting the logs command with a variable server name that ends up empty.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

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AI-assisted analysis of nikivdev/code@a747e741ae (2026-09-01). Data as JSON: /api/errors/7fddb57c2c4f9726. Report an issue: GitHub.