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https://github.com/rsyslog/rsyslog.git
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c780d062c6
Simplify large-scale configs by auto-discovering receivers via DNS SRV records. This reduces per-host configuration and helps enterprise and container setups where target pools change over time. Impact: new param `targetSrv`; config now errors on conflicts or empty SRV answers; feature depends on resolver support. Before: omfwd required a static host/port list via `target`/`port`. After: `targetSrv` resolves `_syslog._udp|_tcp.<domain>` to build the target pool, honoring RFC 2782 priority/weight and reusing existing pool/load-balance logic. Technically, add action param `targetSrv` (mutually exclusive with `target`). During action init, perform SRV query via resolver (`res_nquery`, `ns_initparse`) and translate answers into host/port pairs. Preserve priority; randomly order same-priority entries using weights. If explicit ports were set, warn and ignore when `targetSrv` is used. Link rsyslogd with libresolv when available; configure checks for headers and `ns_initparse`. Provide clear error paths (config check fails) for missing support or empty SRV response. Docs cover usage and env overrides `RSYSLOG_DNS_SERVER`/`RSYSLOG_DNS_PORT`. Tests add a minimal UDP DNS server and cases for TCP/UDP success and error paths. Fixes: https://github.com/rsyslog/rsyslog/issues/6314 With the help of AI Agent: ChatGPT Codex
91 lines
2.2 KiB
Bash
Executable File
91 lines
2.2 KiB
Bash
Executable File
#!/bin/bash
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## @brief Validate SRV discovery for omfwd when resolving targets via DNS SRV over UDP.
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. ${srcdir:=.}/diag.sh init
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check_command_available python3
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export NUMMESSAGES=40
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DNS_RECORDS="$RSYSLOG_DYNNAME.srv.json"
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UDP_PORT=$(get_free_port)
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UDP_OUT="$RSYSLOG_OUT_LOG"
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DNS_PORT_FILE="$RSYSLOG_DYNNAME.dns_port"
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cat >"$DNS_RECORDS" <<EOFJSON
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{
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"SRV": {
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"_syslog._udp.example.test.": [
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{"priority": 5, "weight": 0, "port": $UDP_PORT, "target": "127.0.0.1."}
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]
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}
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}
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EOFJSON
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python3 "$srcdir/dns_srv_mock.py" --port 0 --port-file "$DNS_PORT_FILE" --records "$DNS_RECORDS" &
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DNS_PID=$!
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wait_file_exists "$DNS_PORT_FILE"
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DNS_PORT=$(cat "$DNS_PORT_FILE")
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export RSYSLOG_DNS_SERVER=127.0.0.1
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export RSYSLOG_DNS_PORT="$DNS_PORT"
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export RES_OPTIONS="attempts:1 timeout:1"
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trap 'kill $DNS_PID 2>/dev/null; kill $UDP_PID 2>/dev/null; rm -f "$DNS_PORT_FILE"' EXIT
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python3 - <<'PY' "$UDP_PORT" "$UDP_OUT" "$NUMMESSAGES" &
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import socket
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import sys
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import time
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port = int(sys.argv[1])
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outfile = sys.argv[2]
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expected = int(sys.argv[3])
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sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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sock.bind(("127.0.0.1", port))
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sock.settimeout(15)
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received = 0
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end_time = time.time() + 20
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with open(outfile, "w", encoding="utf-8", errors="ignore") as f:
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while received < expected and time.time() < end_time:
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try:
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data, _ = sock.recvfrom(65535)
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except socket.timeout:
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continue
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message = data.decode(errors="ignore")
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message = message.rstrip("\n")
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f.write(message + "\n")
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f.flush()
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received += 1
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sys.exit(0)
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PY
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UDP_PID=$!
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sleep 1
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generate_conf
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add_conf '
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$MainMsgQueueTimeoutShutdown 10000
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template(name="outfmt" type="string" string="%msg:F,58:2%\n")
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module(load="builtin:omfwd" template="outfmt")
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if $msg contains "msgnum:" then {
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action(type="omfwd" targetSrv="example.test" protocol="udp")
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}
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'
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startup
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injectmsg 0 $NUMMESSAGES
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shutdown_when_empty
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wait_shutdown
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kill $DNS_PID 2>/dev/null
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kill $UDP_PID 2>/dev/null
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rm -f "$DNS_PORT_FILE"
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unset RSYSLOG_DNS_SERVER RSYSLOG_DNS_PORT
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unset RES_OPTIONS
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trap - EXIT
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if [ "$(wc -l < "$UDP_OUT")" -ne "$NUMMESSAGES" ]; then
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echo "Unexpected UDP message count"
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exit 1
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fi
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exit_test
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