Logstream

A simple syslog sink: receives logs over UDP/TCP on port 514, stores them in VictoriaLogs, and serves a clean web interface (light/dark theme, live search, live view, color tags, English/French UI).

devices ──514 udp/tcp──▶ logstream (Go) ──HTTP batches──▶ VictoriaLogs
                              ▲    └── SSE (live) ──▶ browser
                              └──── API / UI ◀─────────┘

Getting started

cp .env.example .env      # optional
docker compose up -d --build
./tools/send-test-logs.sh # sends 100 test messages

Then open http://localhost:8080.

Sending logs

• rsyslog (Linux): add *.* @SERVER_IP:514 (UDP) or *.* @@SERVER_IP:514 (TCP) to /etc/rsyslog.d/90-logstream.conf, then run systemctl restart rsyslog.
• Network gear, NAS, firewalls: set the server IP and port 514 in their "remote syslog" settings.
• Manual test: logger -n 127.0.0.1 -P 514 -d "hello error" (util-linux) or echo "<14>test ok" | nc -u -w1 127.0.0.1 514.

Supported formats: RFC 3164 (BSD) and RFC 5424. Over TCP, both "one message per line" and "octet counting" (RFC 6587) framing are accepted.

Search

Simple mode (default): each word is matched as a case-insensitive substring of the message, host and app. Words are combined with AND.

Input	Meaning
error disk	contains "error" and "disk"
"disk full"	contains the exact phrase
error -timeout	contains "error" but not "timeout"

LogsQL mode (Simple / LogsQL button): the full VictoriaLogs query language, e.g. error AND host:web-01, app:~"ssh|nginx", or * | stats by (host) count(). The live view is disabled in this mode.

Shortcuts: / focuses the search box, Esc clears it. Clicking a row shows all its fields.

Settings

The gear icon opens the settings panel:

• Language: English or French. The choice is remembered in the browser.
• Color tags: each tag has a keyword, a background color (the text automatically switches to black or white to stay readable) and options: whole word, match case, regular expression, active. Tags are stored in /data/tags.json (logstream-data volume). Default tags: warning (orange), error (red), ok (green).

Configuration

Variable	Default	Purpose
SYSLOG_PORT	514	syslog port published on the host
HTTP_PORT	8080	web UI port
RETENTION	30d	how long VictoriaLogs keeps logs
AUTH_USER / AUTH_PASS	empty	HTTP Basic authentication for the UI
TZ	Europe/Paris	time zone for RFC 3164 timestamps (which carry none)
BATCH_SIZE, FLUSH_MS, QUEUE_SIZE	1000, 1000, 100000	ingestion tuning

Debugging

• docker compose logs -f logstream: receive errors and errors sending to VictoriaLogs.
• The bottom bar shows received / stored / dropped counters and the last storage error.
• http://localhost:9428/select/vmui: VictoriaLogs' own UI to try LogsQL queries.
• API:

  curl 'localhost:8080/api/logs?q=error&range=1h&limit=5'   # the response includes the generated LogsQL query
  curl localhost:8080/api/stats
  curl localhost:8080/api/tags
  

• Running outside Docker (Go 1.22+): VLOGS_URL=http://localhost:9428 DATA_DIR=./data SYSLOG_ADDR=:5514 go run .

Code layout

File	Contents
main.go	configuration, startup, authentication
syslog.go	UDP/TCP listeners and RFC 3164 / 5424 parsing
store.go	batched inserts into VictoriaLogs and LogsQL queries
query.go	turns UI filters into LogsQL; live-view filter
hub.go	pushes new messages to browsers (SSE)
tags.go	color tag storage
api.go	/api/* HTTP routes
web/	UI (HTML, CSS, plain JavaScript, no build step), embedded in the binary; translations live in web/app.js (I18N)

Note

With Docker Desktop (macOS/Windows), the source IP seen by the container for UDP packets is the Docker gateway. The host field still comes from the syslog header, which normally carries the sender's real name.