init - no version yet

chorus-script.sh

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+#!/usr/bin/env bash
+
+# State management
+get_state_file() {
+  echo "/tmp/chorus-monitoring-down-hosts.txt"
+}
+
+is_host_down() {
+  local type=$1 host=$2
+  local state_file=$(get_state_file)
+
+  # If state file doesn't exist, host is not down
+  [ ! -f "$state_file" ] && return 1
+
+  # Check if TYPE:HOST exists in state file
+  grep -qxF "${type}:${host}" "$state_file"
+}
+
+mark_host_down() {
+  local type=$1 host=$2
+  local state_file=$(get_state_file)
+
+  # Create file if it doesn't exist
+  touch "$state_file"
+
+  # Only add if not already present (idempotent)
+  if ! grep -qxF "${type}:${host}" "$state_file"; then
+    echo "${type}:${host}" >> "$state_file"
+  fi
+}
+
+mark_host_up() {
+  local type=$1 host=$2
+  local state_file=$(get_state_file)
+
+  # If state file doesn't exist, nothing to remove
+  [ ! -f "$state_file" ] && return 0
+
+  # Remove the TYPE:HOST line from state file
+  sed -i "\|^${type}:${host}$|d" "$state_file"
+}
+
+notify() {
+  local status=$1 type=$2 host=$3
+  local emoji message
+
+  if [[ "$status" == "DOWN" ]]; then
+    emoji="🔴"
+    message="$emoji [$type] $HOSTNAME says $host is DOWN. $(date -u)"
+  else
+    emoji="🟢"
+    message="$emoji [$type] $HOSTNAME says $host is UP. $(date -u)"
+  fi
+
+  curl -s -d "$message" \
+    https://ntfy.uphillsecurity.com/thisisarandomtpic
+  # ADD MAIL AND OTHER METHODS HERE
+}
+
+check_with_retries() {
+  local type=$1 host=$2; shift 2
+
+  for _ in {1..5}; do
+    if "$@"; then
+      echo "$host: reply"
+
+      # Check if host was previously down (state transition: DOWN → UP)
+      if is_host_down "$type" "$host"; then
+        mark_host_up "$type" "$host"
+        notify "UP" "$type" "$host"
+      fi
+
+      return 0
+    fi
+    sleep 1
+  done
+
+  echo "$host: no reply after 5 attempts"
+
+  # Check if host is newly down (state transition: UP → DOWN)
+  if ! is_host_down "$type" "$host"; then
+    mark_host_down "$type" "$host"
+    notify "DOWN" "$type" "$host"
+  fi
+
+  return 1
+}
+
+main() {
+
+  # WHAT TO MONITOR
+  hosts_icmp=("127.0.0.1" "8.8.8.8")
+  hosts_http=("git.uphillsecurity.com" "uphillsecurity.com" "mettwork.com")
+  hosts_tcp=("google.com:443" "uphillsecurity.com:22") # PORT REQUIRED
+
+  # CHECKS
+  for h in "${hosts_icmp[@]}"; do
+    check_with_retries ICMP "$h" \
+      bash -c 'ping -c 1 -W 1 "$1" >/dev/null 2>&1' _ "$h"
+  done
+
+  for h in "${hosts_http[@]}"; do
+    check_with_retries HTTP "$h" \
+      curl -s -o /dev/null --connect-timeout 1 --max-time 2 -f "https://$h"
+  done
+
+  for h in "${hosts_tcp[@]}"; do
+    check_with_retries TCP "$h" \
+      bash -c 'nc -z -w 1 "$1" "$2" >/dev/null 2>&1' _ ${h%:*} ${h##*:}
+  done
+}
+
+main