Faster Previews (Imaginary)

Tested with debian 12

# Imaginary
apt update -y
apt install libvips libvips-dev libopenslide-dev golang pkg-config awk grep bc -y

go install github.com/h2non/imaginary@latest
mv go/bin/imaginary /usr/local/bin/imaginary
chmod +x /usr/local/bin/imaginary
rm -rf go/

cat << EOF > /etc/systemd/system/imaginary.service
[Unit]
Description=Imaginary Service
After=network.target

[Service]
Type=simple
Environment="MALLOC_ARENA_MAX=2"
ExecStart=/usr/local/bin/imaginary -p 9001 -concurrency 20
Restart=on-failure
RestartSec=10s

[Install]
WantedBy=multi-user.target
EOF
systemctl daemon-reload
systemctl enable --now imaginary

# use Imaginary for Preview Generation and use RAM as cache for previews
OCC="sudo -u www-data php /var/www/nextcloud/occ"
$OCC config:system:set enable_previews --value=true
$OCC config:system:set enabledPreviewProviders 0 --value="OC\\Preview\\Imaginary"
$OCC config:system:set preview_imaginary_url --value="http://127.0.0.1:9001"

total_mem_kb=$(grep MemTotal /proc/meminfo | awk '{print $2}')
total_mem_gb=$(echo "scale=2; $total_mem_kb / 1024 / 1024" | bc)
half_mem_gb=$(echo "scale=2; $total_mem_gb / 2" | bc)