Integrate Apache Tomcat 11 with Prometheus and Grafana monitoring for comprehensive performance tracking

#!/usr/bin/env bash

set -euo pipefail

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

# Configuration
TOMCAT_VERSION="11.0.0"
PROMETHEUS_JMX_VERSION="0.20.0"
PROMETHEUS_VERSION="2.45.0"
GRAFANA_VERSION="10.0.0"

# Function to print colored output
print_status() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

print_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# Usage message
usage() {
    echo "Usage: $0 [OPTIONS]"
    echo "Options:"
    echo "  -h, --help     Show this help message"
    echo "  --metrics-port Port for JMX metrics (default: 9090)"
    echo ""
    echo "Example: $0 --metrics-port 9091"
    exit 1
}

# Parse arguments
METRICS_PORT=9090

while [[ $# -gt 0 ]]; do
    case $1 in
        -h|--help)
            usage
            ;;
        --metrics-port)
            METRICS_PORT="$2"
            shift 2
            ;;
        *)
            echo "Unknown option: $1"
            usage
            ;;
    esac
done

# Cleanup function
cleanup() {
    print_error "Installation failed. Cleaning up..."
    systemctl stop tomcat 2>/dev/null || true
    systemctl stop prometheus 2>/dev/null || true
    systemctl stop grafana-server 2>/dev/null || true
    rm -rf /opt/tomcat /opt/prometheus /tmp/tomcat-install-*
}

trap cleanup ERR

# Check if running as root
if [[ $EUID -ne 0 ]]; then
    print_error "This script must be run as root"
    exit 1
fi

print_status "[1/12] Detecting distribution and package manager..."

# Auto-detect distro
if [ -f /etc/os-release ]; then
    . /etc/os-release
    case "$ID" in
        ubuntu|debian) 
            PKG_MGR="apt"
            PKG_UPDATE="apt update"
            PKG_INSTALL="apt install -y"
            JAVA_PACKAGE="openjdk-11-jdk"
            ;;
        almalinux|rocky|centos|rhel|ol|fedora) 
            PKG_MGR="dnf"
            PKG_UPDATE="dnf update -y"
            PKG_INSTALL="dnf install -y"
            JAVA_PACKAGE="java-11-openjdk-devel"
            ;;
        amzn) 
            PKG_MGR="yum"
            PKG_UPDATE="yum update -y"
            PKG_INSTALL="yum install -y"
            JAVA_PACKAGE="java-11-amazon-corretto-devel"
            ;;
        *) 
            print_error "Unsupported distribution: $ID"
            exit 1
            ;;
    esac
else
    print_error "Cannot detect distribution"
    exit 1
fi

print_status "Detected: $PRETTY_NAME using $PKG_MGR"

print_status "[2/12] Updating system packages..."
$PKG_UPDATE

print_status "[3/12] Installing required packages..."
$PKG_INSTALL $JAVA_PACKAGE wget curl tar

print_status "[4/12] Creating tomcat user..."
if ! id tomcat &>/dev/null; then
    useradd -r -m -U -d /opt/tomcat -s /bin/false tomcat
fi

print_status "[5/12] Downloading and installing Apache Tomcat $TOMCAT_VERSION..."
cd /tmp
TOMCAT_TARBALL="apache-tomcat-${TOMCAT_VERSION}.tar.gz"
if [ ! -f "$TOMCAT_TARBALL" ]; then
    wget "https://archive.apache.org/dist/tomcat/tomcat-11/v${TOMCAT_VERSION}/bin/${TOMCAT_TARBALL}"
fi

mkdir -p /opt/tomcat
tar xf "$TOMCAT_TARBALL" -C /opt/tomcat --strip-components=1
chown -R tomcat:tomcat /opt/tomcat
chmod +x /opt/tomcat/bin/*.sh

print_status "[6/12] Downloading JMX Prometheus Java agent..."
cd /opt/tomcat/lib
wget -O jmx_prometheus_javaagent-${PROMETHEUS_JMX_VERSION}.jar \
    "https://repo1.maven.org/maven2/io/prometheus/jmx/jmx_prometheus_javaagent/${PROMETHEUS_JMX_VERSION}/jmx_prometheus_javaagent-${PROMETHEUS_JMX_VERSION}.jar"
chown tomcat:tomcat jmx_prometheus_javaagent-${PROMETHEUS_JMX_VERSION}.jar

print_status "[7/12] Creating JMX exporter configuration..."
cat > /opt/tomcat/conf/jmx-config.yml << 'EOF'
rules:
  # JVM Memory metrics
  - pattern: 'java.lang<type=Memory><HeapMemoryUsage>(\w+)'
    name: jvm_memory_heap_bytes
    type: GAUGE
    labels:
      area: "heap"
      type: "$1"
  
  # Thread metrics
  - pattern: 'java.lang<type=Threading><>ThreadCount'
    name: jvm_threads_current
    type: GAUGE
  
  # GC metrics
  - pattern: 'java.lang<type=GarbageCollector, name=(\w+)><>CollectionCount'
    name: jvm_gc_collections_total
    type: COUNTER
    labels:
      gc: "$1"
  
  # Tomcat connector metrics
  - pattern: 'Catalina<type=ThreadPool, name="([^"]+)"><>currentThreadCount'
    name: tomcat_threads_current
    type: GAUGE
    labels:
      connector: "$1"
  
  - pattern: 'Catalina<type=GlobalRequestProcessor, name="([^"]+)"><>requestCount'
    name: tomcat_requests_total
    type: COUNTER
    labels:
      connector: "$1"
EOF

chown tomcat:tomcat /opt/tomcat/conf/jmx-config.yml
chmod 644 /opt/tomcat/conf/jmx-config.yml

print_status "[8/12] Configuring Tomcat with JMX agent..."
cat > /opt/tomcat/bin/setenv.sh << EOF
CATALINA_OPTS="\$CATALINA_OPTS -javaagent:/opt/tomcat/lib/jmx_prometheus_javaagent-${PROMETHEUS_JMX_VERSION}.jar=${METRICS_PORT}:/opt/tomcat/conf/jmx-config.yml"
CATALINA_OPTS="\$CATALINA_OPTS -Dcom.sun.management.jmxremote"
CATALINA_OPTS="\$CATALINA_OPTS -Dcom.sun.management.jmxremote.port=9999"
CATALINA_OPTS="\$CATALINA_OPTS -Dcom.sun.management.jmxremote.authenticate=false"
CATALINA_OPTS="\$CATALINA_OPTS -Dcom.sun.management.jmxremote.ssl=false"
EOF

chown tomcat:tomcat /opt/tomcat/bin/setenv.sh
chmod 755 /opt/tomcat/bin/setenv.sh

print_status "[9/12] Creating Tomcat systemd service..."
cat > /etc/systemd/system/tomcat.service << EOF
[Unit]
Description=Apache Tomcat Web Application Container
After=network.target

[Service]
Type=forking

Environment=JAVA_HOME=/usr/lib/jvm/java-11-openjdk
Environment=CATALINA_PID=/opt/tomcat/temp/tomcat.pid
Environment=CATALINA_HOME=/opt/tomcat
Environment=CATALINA_BASE=/opt/tomcat
Environment='CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC'
Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom'

ExecStart=/opt/tomcat/bin/startup.sh
ExecStop=/opt/tomcat/bin/shutdown.sh

User=tomcat
Group=tomcat
UMask=0007
RestartSec=10
Restart=always

[Install]
WantedBy=multi-user.target
EOF

print_status "[10/12] Installing Prometheus..."
cd /tmp
PROMETHEUS_TARBALL="prometheus-${PROMETHEUS_VERSION}.linux-amd64.tar.gz"
if [ ! -f "$PROMETHEUS_TARBALL" ]; then
    wget "https://github.com/prometheus/prometheus/releases/download/v${PROMETHEUS_VERSION}/${PROMETHEUS_TARBALL}"
fi

useradd -r -s /bin/false prometheus 2>/dev/null || true
mkdir -p /opt/prometheus /var/lib/prometheus
tar xf "$PROMETHEUS_TARBALL" -C /opt/prometheus --strip-components=1
chown -R prometheus:prometheus /opt/prometheus /var/lib/prometheus

print_status "[11/12] Configuring Prometheus..."
cat > /opt/prometheus/prometheus.yml << EOF
global:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'tomcat'
    static_configs:
      - targets: ['localhost:${METRICS_PORT}']
    scrape_interval: 5s
    metrics_path: /metrics
EOF

chown prometheus:prometheus /opt/prometheus/prometheus.yml

# Create Prometheus systemd service
cat > /etc/systemd/system/prometheus.service << EOF
[Unit]
Description=Prometheus
After=network.target

[Service]
User=prometheus
Group=prometheus
Type=simple
ExecStart=/opt/prometheus/prometheus --config.file=/opt/prometheus/prometheus.yml --storage.tsdb.path=/var/lib/prometheus --web.console.templates=/opt/prometheus/consoles --web.console.libraries=/opt/prometheus/console_libraries --web.listen-address=0.0.0.0:9091

[Install]
WantedBy=multi-user.target
EOF

print_status "[12/12] Installing Grafana..."
case "$ID" in
    ubuntu|debian)
        wget -q -O - https://packages.grafana.com/gpg.key | apt-key add -
        echo "deb https://packages.grafana.com/oss/deb stable main" > /etc/apt/sources.list.d/grafana.list
        apt update
        apt install -y grafana
        ;;
    *)
        cat > /etc/yum.repos.d/grafana.repo << EOF
[grafana]
name=grafana
baseurl=https://packages.grafana.com/oss/rpm
repo_gpgcheck=1
enabled=1
gpgcheck=1
gpgkey=https://packages.grafana.com/gpg.key
sslverify=1
sslcacert=/etc/pki/tls/certs/ca-bundle.crt
EOF
        $PKG_INSTALL grafana
        ;;
esac

# Configure firewall
if command -v firewall-cmd &> /dev/null; then
    firewall-cmd --permanent --add-port=8080/tcp
    firewall-cmd --permanent --add-port=${METRICS_PORT}/tcp
    firewall-cmd --permanent --add-port=9091/tcp
    firewall-cmd --permanent --add-port=3000/tcp
    firewall-cmd --reload
elif command -v ufw &> /dev/null; then
    ufw allow 8080/tcp
    ufw allow ${METRICS_PORT}/tcp
    ufw allow 9091/tcp
    ufw allow 3000/tcp
fi

# Start services
systemctl daemon-reload
systemctl enable tomcat prometheus grafana-server
systemctl start tomcat
sleep 5
systemctl start prometheus
systemctl start grafana-server

print_status "Installation completed successfully!"
print_status "Services:"
print_status "  Tomcat: http://localhost:8080"
print_status "  Tomcat Metrics: http://localhost:${METRICS_PORT}/metrics"
print_status "  Prometheus: http://localhost:9091"
print_status "  Grafana: http://localhost:3000 (admin/admin)"
print_warning "Please change the default Grafana password on first login"

# Verification
sleep 10
if curl -s http://localhost:${METRICS_PORT}/metrics > /dev/null; then
    print_status "✓ Tomcat metrics endpoint is responding"
else
    print_error "✗ Tomcat metrics endpoint is not responding"
fi

if curl -s http://localhost:9091/-/healthy > /dev/null; then
    print_status "✓ Prometheus is healthy"
else
    print_error "✗ Prometheus is not responding"
fi

if curl -s http://localhost:3000/api/health > /dev/null; then
    print_status "✓ Grafana is responding"
else
    print_error "✗ Grafana is not responding"
fi