Initial commit

2026-06-30 07:17:40 -04:00 · 2026-06-07 13:55:01 -04:00
commit 3dde79cfe2
5 changed files with 249 additions and 0 deletions
@@ -0,0 +1,115 @@
+#!/bin/bash
+# Save to: ~/.ssh/ssh-failover.sh
+
+TARGET_HOST="$1"
+CONFIG_DIR="$HOME/.ssh/hosts.d"
+
+# Force lower-case comparison to prevent case mismatches from SSH %h token
+TARGET_LOWER=$(echo "$TARGET_HOST" | tr '[:upper:]' '[:lower:]')
+CONFIG_FILE="$CONFIG_DIR/proxyrule.${TARGET_LOWER}.conf"
+
+TIMEOUT=0.5
+DEBUG=${DEBUG:-false}
+
+if [ ! -f "$CONFIG_FILE" ]; then
+    echo "FAILOVER ERROR: Config file missing at $CONFIG_FILE" >&2
+    exit 1
+fi
+
+source "$CONFIG_FILE"
+
+if [ ${#ENDPOINTS[@]} -eq 0 ]; then
+    echo "FAILOVER ERROR: No ENDPOINTS array found inside $CONFIG_FILE" >&2
+    exit 1
+fi
+
+# Helper function to resolve hostnames to IP addresses before the timer starts
+resolve_to_ip() {
+    local target=$1
+    # Check if it's already an IPv4 or IPv6 address to save process execution
+    if [[ "$target" =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ || "$target" =~ : ]]; then
+        echo "$target"
+    else
+        # Resolve using standard system hosts databases (handles DNS, /etc/hosts, etc.)
+        local ip
+        ip=$(getent hosts "$target" | awk '{print $1; exit}')
+        # Fall back to dig if getent isn't providing a quick single target ip
+        [ -z "$ip" ] && ip=$(dig +short "$target" | tail -n1)
+        # If both fail, return original target so nc can try anyway
+        echo "${ip:-$target}"
+    fi
+}
+
+get_tcp_ms() {
+    local host=$1
+    local port=$2
+    local start=$EPOCHREALTIME
+    
+    if timeout "$TIMEOUT" nc -z "$host" "$port" 2>/dev/null; then
+        local end=$EPOCHREALTIME
+        awk "BEGIN {print int(($end - $start) * 1000)}"
+    else
+        echo "9999"
+    fi
+}
+
+declare -a results
+declare -a resolved_hosts
+fastest_ms=9999
+chosen_index=""
+
+for ((i=0; i<${#ENDPOINTS[@]}; i++)); do
+    IFS="|" read -r label host port <<< "${ENDPOINTS[$i]}"
+    
+    # CRITICAL BUGFIX: Strip any hidden trailing newlines (\n) or carriage returns (\r)
+    port=$(echo "$port" | tr -d '\r\n[:space:]')
+    
+    # Pre-resolve hostnames to eliminate DNS lookup latency skew
+    resolved_host=$(resolve_to_ip "$host")
+    resolved_hosts[$i]=$resolved_host
+    
+    ms=$(get_tcp_ms "$resolved_host" "$port")
+    results[$i]=$ms
+    
+    # if [ "$DEBUG" = true ]; then
+    #     echo "Comparing $ms to $fastest_ms"
+    # fi
+
+    if [ "$ms" -lt "$fastest_ms" ]; then
+        fastest_ms=$ms
+        chosen_index=$i
+    fi
+done
+
+# --- DYNAMIC DEBUG DISPLAY LOOP ---
+if [ "$DEBUG" = true ]; then
+    echo "--------------------------------------------------------" >&2
+    printf "Testing routes for: \e[1;34m%s\e[0m\n" "$TARGET_HOST" >&2
+    echo "--------------------------------------------------------" >&2
+    printf "%-25s | %-12s | %-10s\n" "Endpoint / Host" "Status" "Latency" >&2
+    echo "--------------------------------------------------------" >&2
+    
+    for ((i=0; i<${#ENDPOINTS[@]}; i++)); do
+        IFS="|" read -r label host port <<< "${ENDPOINTS[$i]}"
+        ms=${results[$i]}
+        
+        if [ "$ms" -eq 9999 ]; then
+            printf "%-25s | \e[31m%-12s\e[0m | %-10s\n" "$label" "OFFLINE" "---" >&2
+        else
+            printf "%-25s | \e[32m%-12s\e[0m | %-10s\n" "$label" "ONLINE" "${ms}ms" >&2
+        fi
+    done
+    echo "--------------------------------------------------------" >&2
+fi
+
+# 2. Route traffic to the fastest endpoint found
+if [ -n "$chosen_index" ] && [ "$fastest_ms" -lt 9999 ]; then
+    IFS="|" read -r label host port <<< "${ENDPOINTS[$chosen_index]}"
+    port=$(echo "$port" | tr -d '\r\n[:space:]')
+    
+    [ "$DEBUG" = true ] && echo "-> Routing via $label ($host:$port)..." >&2
+    exec nc "$host" "$port"
+else
+    echo "FAILOVER ERROR: All paths to $TARGET_HOST are dead." >&2
+    exit 1
+fi