DiscordLogger — Valheim BepInEx Mod

Pipes all BepInEx log output to a Discord webhook in near-real-time, with local buffering so no lines are lost on unexpected process death.

How It Works

Every log line
      │
      ▼
BepInEx/DiscordLogBuffer.txt   ← flushed to disk immediately, every line
      │
      ▼ (every N seconds, background thread)
Discord Webhook POST
      │
      ├─ read from front of buffer
      ├─── success (200) → remove read lines from front.
      └─── failure (500) → leave buffer, retry next tick

On next startup:
  buffer file exists? → send as "recovered from crash" → delete → begin fresh

Build

Requirements: .NET SDK with netstandard2.1 support (i.e. .NET Core 3.0+ or .NET 5+ SDK), dotnet CLI, Valheim dedicated server + BepInEx installed.

Targets netstandard2.1, which runs on Unity's Mono 6.4+ runtime. Not compatible with plain .NET Framework 4.7.2.

The .csproj assumes the default Linux Steam dedicated server path:

~/.steam/steam/steamapps/common/Valheim dedicated server

Edit the <ValheimDir> property if your path differs.

dotnet build -c Release

Output: bin/Release/netstandard2.1/DiscordLogger.dll

Install

1. Copy DiscordLogger.dll into BepInEx/plugins/
2. Launch the game once to generate the config file
3. Open BepInEx/config/com.byawn.DiscordLogSync.cfg
4. Set your webhook URL:

[Discord]
WebhookUrl = https://discord.com/api/webhooks/YOUR_ID/YOUR_TOKEN
SendIntervalSeconds = 3
MaxMessageChars = 1800

1. Restart

Config Options

Buffer File

BepInEx/DiscordLogBuffer.txt

• Created fresh each run
• Every line flushed to disk immediately (no in-memory buffering)
• If the file exists on startup → previous run crashed → contents sent as recovery message
• Treated like a FIFO so as to fit inside Discord message size limits.

Discord Message Colors [UNUSED FEATURE?]

1.0.4

• Updated BepInEx dependency to 5.4.2333

1.0.3

• Windows compatibility for RawStdout source — the fd-level pipe intercept now works on Windows via P/Invoke into ucrtbase.dll (_dup, _dup2, _pipe, _read, _write, _close). This works because ucrtbase.dll is the Universal CRT shared across Unity's native engine and all managed code in the process.

  Silent failure mode: If the Unity build were statically linked against the CRT (extremely unlikely on modern Unity 6), _dup2 would still succeed but Unity's native writes would go to a separate fd table, never passing through the pipe. The plugin would start cleanly and BepInEx-sourced lines would still appear in Discord — but world save lines and other native stdout output would be silently absent. You would only notice by their absence. On Linux this concern does not apply.

1.0.2

• Add configurable Source setting: BepInEx (default), Console, or RawStdout
• BepInEx — original ILogListener approach, unchanged
• Console — intercepts managed Console.Out via Console.SetOut()
• RawStdout — experimental, Linux only; intercepts stdout at the OS file descriptor level using pipe()+dup2(), capturing world saves, ZDO counts, and all native stdout writes that bypass BepInEx entirely. Falls back to BepInEx source on init failure.
• Fix recovery message title to include server name and timestamp
• Fix shutdown message to use consistent em-dash formatting

1.0.1

• Add server name and timestamp to the message title
• Don't double up timestamps in the message content
• Show log event source and level

1.0.0

• Initial release
• Pipes all BepInEx and Unity logs to a Discord webhook in near-real-time
• Local buffer file flushed on every line — nothing lost on unexpected shutdown
• FIFO queue — oldest logs sent first, catches up automatically after bursts
• Crash recovery — leftover buffer from previous session sent on next startup flagged as recovered
• Configurable send interval and max message size