Files
skywatch/agent/skywatch-agent.sh
T
nmemmertandClaude Sonnet 4.6 06e8e64a0b Add Linux agent: metrics collection + server API + installer
- agent/skywatch-agent.sh: bash daemon that collects CPU, memory, disk,
  network, load, and uptime, then POSTs to /api/agents/report every 60 s
- agent/install-agent.sh: systemd installer; registers agent on first run
- server/database.js: adds `agents` and `agent_metrics` tables with indexes
- server/index.js: adds agent API routes (register, report, list, history,
  delete, script/installer download); optional AGENT_REGISTRATION_KEY guard

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-08-11 10:01:45 -04:00

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8.8 KiB
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#!/bin/bash
# SkyWatch Linux Agent v1.0.0
# Collects system metrics and sends to SkyWatch monitoring server
#
# Metrics: CPU %, Memory, Disk, Network I/O, Load Average, Process Count
# Requirements: bash 4+, curl, awk, df, /proc filesystem (standard Linux)
#
# Usage:
# Configured via CONFIG_FILE (default /etc/skywatch-agent.conf)
# Run via systemd (see install-agent.sh) or: bash skywatch-agent.sh
VERSION="1.0.0"
CONFIG_FILE="${CONFIG_FILE:-/etc/skywatch-agent.conf}"
LOG_FILE="${LOG_FILE:-/var/log/skywatch-agent.log}"
# Fall back to home dir if system paths aren't writable
if [ ! -w "$(dirname "$CONFIG_FILE")" ] 2>/dev/null; then
CONFIG_FILE="$HOME/.skywatch-agent.conf"
LOG_FILE="$HOME/.skywatch-agent.log"
fi
log() {
local ts
ts=$(date '+%Y-%m-%d %H:%M:%S' 2>/dev/null || echo "")
local msg="[$ts] $*"
echo "$msg" >> "$LOG_FILE" 2>/dev/null || true
echo "$msg"
}
load_config() {
if [ -f "$CONFIG_FILE" ]; then
# shellcheck disable=SC1090
source "$CONFIG_FILE"
fi
}
save_config() {
cat > "$CONFIG_FILE" << CONF
SKYWATCH_URL="${SKYWATCH_URL:-}"
AGENT_TOKEN="${AGENT_TOKEN:-}"
REPORT_INTERVAL="${REPORT_INTERVAL:-60}"
AGENT_NAME="${AGENT_NAME:-}"
REGISTRATION_KEY="${REGISTRATION_KEY:-}"
CONF
chmod 600 "$CONFIG_FILE" 2>/dev/null || true
}
# CPU usage % — reads /proc/stat twice 1 second apart (that 1s is intentional)
get_cpu_percent() {
local s1 s2
s1=$(grep '^cpu ' /proc/stat 2>/dev/null) || { echo "0.0"; return; }
sleep 1
s2=$(grep '^cpu ' /proc/stat 2>/dev/null) || { echo "0.0"; return; }
awk -v s1="$s1" -v s2="$s2" 'BEGIN {
n = split(s1, a)
split(s2, b)
t1 = 0; t2 = 0
for (i = 2; i <= n; i++) { t1 += a[i]; t2 += b[i] }
# idle + iowait (indices 5 and 6 in the array, which is index 4+5 in /proc/stat)
idle1 = a[5] + a[6]
idle2 = b[5] + b[6]
dt = t2 - t1
di = idle2 - idle1
if (dt <= 0) { printf "0.0"; exit }
printf "%.1f", (dt - di) * 100 / dt
}'
}
# Memory stats in MB
get_memory() {
awk '
/^MemTotal:/ { total = int($2 / 1024) }
/^MemAvailable:/{ avail = int($2 / 1024) }
END {
used = total - avail
pct = (total > 0) ? used * 100.0 / total : 0
printf "%d %d %.1f", total, used, pct
}
' /proc/meminfo 2>/dev/null || echo "0 0 0.0"
}
# Disk info as a JSON array — real block devices only, no tmpfs/overlay
get_disk_json() {
df -P -k \
-x tmpfs -x devtmpfs -x squashfs -x overlay \
2>/dev/null \
| tail -n +2 \
| grep '^/' \
| awk '
BEGIN { printf "["; c = 0 }
{
sub(/%/, "", $5)
mp = $6
# JSON-escape the mount path
gsub(/\\/, "\\\\", mp)
gsub(/"/, "\\\"", mp)
if (c > 0) printf ","
printf "{\"path\":\"%s\",\"total_mb\":%d,\"used_mb\":%d,\"percent\":%d}",
mp, int($2 / 1024), int($3 / 1024), $5
c++
}
END { printf "]" }
'
}
# Cumulative network bytes since boot (all interfaces except loopback)
get_net_bytes() {
awk '
/:/ && !/lo:/ {
split($0, parts, ":")
split(parts[2], f)
recv += f[1] # receive bytes
sent += f[9] # transmit bytes
}
END { printf "%d %d", sent, recv }
' /proc/net/dev 2>/dev/null || echo "0 0"
}
# 1/5/15-minute load averages
get_load() {
awk '{ printf "%s %s %s", $1, $2, $3 }' /proc/loadavg 2>/dev/null || echo "0.00 0.00 0.00"
}
# System uptime in whole seconds
get_uptime_seconds() {
awk '{ printf "%d", $1 }' /proc/uptime 2>/dev/null || echo "0"
}
# Number of running processes
get_process_count() {
ls -d /proc/[0-9]* 2>/dev/null | wc -l | tr -d ' \n'
}
# Primary non-loopback IPv4 address
get_ip_address() {
if command -v ip &>/dev/null; then
ip -4 route get 1.1.1.1 2>/dev/null \
| awk '/src/ { for(i=1;i<=NF;i++) if($i=="src"){ print $(i+1); exit } }'
elif command -v hostname &>/dev/null; then
hostname -I 2>/dev/null | awk '{print $1}'
fi
}
# OS description string
get_os_info() {
if [ -f /etc/os-release ]; then
# shellcheck disable=SC1091
. /etc/os-release
echo "${PRETTY_NAME:-${NAME:-Linux}}"
else
uname -sr
fi
}
# Register this host with the server; saves token to config on success
register_agent() {
local name="${AGENT_NAME:-$(hostname -f 2>/dev/null || hostname)}"
local hostname_val
hostname_val=$(hostname -f 2>/dev/null || hostname)
local ip
ip=$(get_ip_address || echo "")
local os
os=$(get_os_info)
# Sanitize values for JSON string embedding
local esc_name esc_host esc_os
esc_name="${name//\"/\\\"}"
esc_host="${hostname_val//\"/\\\"}"
esc_os="${os//\"/\\\"}"
log "Registering agent '${name}' with ${SKYWATCH_URL} ..."
# Build curl args as an array so we can conditionally add the registration key header
local -a curl_args
curl_args=(-sf -m 30 -X POST -H 'Content-Type: application/json')
[ -n "${REGISTRATION_KEY:-}" ] && curl_args+=(-H "X-Registration-Key: ${REGISTRATION_KEY}")
curl_args+=(-d "{\"name\":\"${esc_name}\",\"hostname\":\"${esc_host}\",\"ip_address\":\"${ip}\",\"os_info\":\"${esc_os}\"}")
curl_args+=("${SKYWATCH_URL}/api/agents/register")
local response
response=$(curl "${curl_args[@]}" 2>&1) || {
log "ERROR: Could not reach ${SKYWATCH_URL} during registration"
return 1
}
local token
token=$(echo "$response" | grep -o '"token":"[^"]*"' | sed 's/"token":"//; s/"$//')
if [ -z "$token" ]; then
log "ERROR: Registration failed. Server said: ${response}"
return 1
fi
AGENT_TOKEN="$token"
save_config
log "Registered. Token stored in ${CONFIG_FILE}"
}
# Collect all metrics and POST to /api/agents/report
report_metrics() {
local cpu
cpu=$(get_cpu_percent) # includes built-in 1 s sleep
local mem_total mem_used mem_percent
read -r mem_total mem_used mem_percent <<< "$(get_memory)"
local disk
disk=$(get_disk_json)
local net_sent net_recv
read -r net_sent net_recv <<< "$(get_net_bytes)"
local load1 load5 load15
read -r load1 load5 load15 <<< "$(get_load)"
local uptime_secs
uptime_secs=$(get_uptime_seconds)
local procs
procs=$(get_process_count)
local ip
ip=$(get_ip_address || echo "")
# Fallbacks so we always produce valid JSON
cpu="${cpu:-0.0}"
mem_total="${mem_total:-0}"
mem_used="${mem_used:-0}"
mem_percent="${mem_percent:-0.0}"
disk="${disk:-[]}"
net_sent="${net_sent:-0}"
net_recv="${net_recv:-0}"
load1="${load1:-0.00}"
load5="${load5:-0.00}"
load15="${load15:-0.00}"
uptime_secs="${uptime_secs:-0}"
procs="${procs:-0}"
local payload
payload=$(printf \
'{"cpu_percent":%s,"mem_total":%d,"mem_used":%d,"mem_percent":%s,"disk":%s,"load_1":%s,"load_5":%s,"load_15":%s,"uptime_seconds":%d,"process_count":%d,"net_bytes_sent":%s,"net_bytes_recv":%s,"ip_address":"%s"}' \
"$cpu" "$mem_total" "$mem_used" "$mem_percent" \
"$disk" "$load1" "$load5" "$load15" \
"$uptime_secs" "$procs" \
"$net_sent" "$net_recv" \
"${ip}")
local response
response=$(curl -sf -m 15 \
-X POST \
-H 'Content-Type: application/json' \
-H "Authorization: Bearer ${AGENT_TOKEN}" \
-d "$payload" \
"${SKYWATCH_URL}/api/agents/report" 2>&1) || {
log "WARNING: Failed to send metrics (network error)"
return 0
}
if echo "$response" | grep -q '"ok":true'; then
log "OK cpu=${cpu}% mem=${mem_used}/${mem_total}MB load=${load1}"
else
log "WARNING: Server rejected metrics: ${response}"
fi
}
main() {
load_config
if [ -z "${SKYWATCH_URL:-}" ]; then
echo "ERROR: SKYWATCH_URL is not set."
echo ""
echo "Create ${CONFIG_FILE} containing:"
echo " SKYWATCH_URL=\"http://<your-server>:3001\""
echo ""
echo "Or use the installer:"
echo " sudo bash install-agent.sh --server-url http://<your-server>:3001"
exit 1
fi
# Register on first run (no token stored yet)
if [ -z "${AGENT_TOKEN:-}" ]; then
if ! register_agent; then
log "Retrying registration in 60 s..."
sleep 60
register_agent || exit 1
fi
fi
local interval="${REPORT_INTERVAL:-60}"
log "SkyWatch Agent v${VERSION} started — server=${SKYWATCH_URL} interval=${interval}s"
while true; do
report_metrics
# get_cpu_percent already consumed ~1 s; subtract it from the sleep
local sleep_time=$(( interval - 1 ))
[ "$sleep_time" -lt 1 ] && sleep_time=1
sleep "$sleep_time"
done
}
main "$@"