Start Snapclient

snapclient.service

[Unit]
Description=Snapclient for Speakers
After=network.target sound.target

[Service]
User=speaker
ExecStart=/usr/local/bin/start_snapcast.sh 10.x.x.x CLIENT_NUMBER /dev/snd/by-id/usb-Creative_Technology_Ltd_Sound_Blaster_Play__3_YDSB1730431006108F-00
Restart=on-failure

[Install]
WantedBy=multi-user.target

start_snapclient.sh

#!/bin/bash

# Usage check
if [[ $# -ne 3 ]]; then
  echo "Usage: $0 <snapserver_hostname> <snapclient_instance_number> <path_to_by-id_symlink>"
  exit 1
fi

SNAPSERVER_HOSTNAME="$1"
INSTANCE_ID="$2"
BYID_PATH="$3"

# Check if the path exists
if [[ ! -e "$BYID_PATH" ]]; then
  echo "Error: '$BYID_PATH' does not exist."
  exit 2
fi

# Resolve to actual ALSA device path
REAL_DEV=$(readlink -f "$BYID_PATH")

# Extract card number (e.g., controlC3 → 3)
if [[ "$REAL_DEV" =~ controlC([0-9]+) ]]; then
  CARD_NUM="${BASH_REMATCH[1]}"
else
  echo "Error: Couldn't extract card number from '$REAL_DEV'"
  exit 3
fi

# Read the ALSA card ID (e.g., S3, S4_1, etc.)
CARD_ID_FILE="/proc/asound/card${CARD_NUM}/id"
if [[ ! -f "$CARD_ID_FILE" ]]; then
  echo "Error: Card ID file not found at '$CARD_ID_FILE'"
  exit 4
fi

CARD_ID=$(cat "$CARD_ID_FILE")

# Run snapclient -l and extract matching line
DEVICE_LINE=$(snapclient -l | grep -E "^[0-9]+: plughw:CARD=${CARD_ID},DEV=0")

if [[ -z "$DEVICE_LINE" ]]; then
  echo "Error: No matching plughw device found for ALSA ID '$CARD_ID'"
  exit 2
fi

# Extract the device number (e.g., 55:)
DEVICE_NUM=$(echo "$DEVICE_LINE" | awk -F: '{print $1}' | xargs)

# Output result
echo "Instance ID: $INSTANCE_ID"
echo "ALSA Card Number: $CARD_NUM"
echo "ALSA Card ID: $CARD_ID"
echo "Snapclient Device Number: $DEVICE_NUM"

# Adjust volume to 100%
echo "Adjusting volume..."
amixer -c $CARD_NUM set Speaker 100%

# Start snapclient
echo "Starting snapclient..."

snapclient -h $SNAPSERVER_HOSTNAME -s $DEVICE_NUM -i $INSTANCE_ID