fix: raise fd limit at startup and fail fast when hard limit is too low

[janx]

Fixes #4

Goal

• Prevent "Too many open files" crash during bulk sync on macOS, including when the hard fd limit is also too low

Principle Alignment

• Fail Fast, Fail Early: detect and reject insufficient fd limits before the indexer starts, with an actionable OS-specific fix message

Result

• raise_fd_limit() tries to raise both hard and soft limits to 65536; if the hard-limit raise is denied (EPERM), falls back to raising soft to the current hard ceiling
• check_fd_limit_for_indexer() fails fast with an actionable error if the effective limit is below 4096 after the raise attempt
• Startup banner shows effective fd limit; yellow WARNING if below minimum
• Re-sync required: no
• What to do next: verify on macOS with a restrictive launchctl config

Generated with Claude Code

[Copilot]

Pull request overview

Adds startup-time file descriptor (fd) limit management to reduce “Too many open files” failures during RocksDB-heavy bulk sync, and to fail fast when the effective limit is insufficient.

Changes:

• Introduces raise_fd_limit() (best-effort) and check_fd_limit_for_indexer() (fail-fast below a minimum threshold).
• Displays the effective fd limit in the startup system line (with conditional warning formatting).
• Adds unit tests covering fd-limit helpers and updates existing print_startup_info call sites.

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[janx]

@claude fix failed checks

[claude]

Claude finished @janx's task in 1m 53s —— View job

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Fixed failed checks

• Check CI status to identify failing checks — cargo fmt check failed in "Rust Check & Lint"
• Read the changed file to understand the current code
• Fix the formatting issue — each format arg in check_fd_limit_for_indexer now on its own line (matching what rustfmt expected)
• Push fix

Root cause: rustfmt requires each argument in a long format macro call to be on its own line. The args fd_limit, FD_LIMIT_MIN, FD_LIMIT_TARGET, FD_LIMIT_TARGET, FD_LIMIT_TARGET, FD_LIMIT_TARGET were packed two-per-line; the fix puts one per line (crates/cli/src/main.rs:135-140).
· Branch

[janx]

@claude check copilot review comments

[claude]

Claude finished @janx's task in 3m 57s —— View job

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Fixed Copilot review comments

• Read crates/cli/src/main.rs to understand current code
• Comment 1 (line 364): services.contains(&"indexer".to_string()) → services.iter().any(|s| s == "indexer") — avoids String allocation
• Comment 2 (line 61): silent return 0 on getrlimit failure → raise_fd_limit() now returns Result<u64> and bails with the OS error, so users see "getrlimit(RLIMIT_NOFILE) failed: …" instead of "fd limit 0 is too low"
• Comment 3 (line 773): WARNING banner threshold changed from fd_limit < FD_LIMIT_MIN (unreachable when indexer runs, since we bail! before print_startup_info) to fd_limit < FD_LIMIT_TARGET — now shows a useful yellow warning when the limit was raised but couldn't reach 65536 (e.g., hard limit capped at 8192)
• Update two raise_fd_limit tests to .expect(...) the new Result
• Pushed as commit e860177
  · Branch