110 lines
3.2 KiB
Bash
110 lines
3.2 KiB
Bash
#!/bin/dash
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# sentinel.sh — polls probe backends (/status) and notifies on status change via Telegram
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# Env:
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# SERVERS="http://host1:8080,http://host2:8080"
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# TOKENS="-,b64token2" # CSV aligned with SERVERS; "-" means no auth
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# TOKEN="..." # Telegram bot token
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# CHAT_ID="..." # Telegram chat id
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# TIMEOUT=5 # curl timeout seconds (default 5)
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# POLLING_INTERVAL_SEC=3 # default 3
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# STATE_DIR=/tmp/sentinel # default /tmp/sentinel
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set -eu
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TIMEOUT=${TIMEOUT:-5}
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POLLING_INTERVAL_SEC=${POLLING_INTERVAL_SEC:-3}
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STATE_DIR=${STATE_DIR:-$(mktemp -d)}
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SERVERS=${SERVERS:-}
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TOKENS=${TOKENS:-}
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TOKEN=${TOKEN:-}
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CHAT_ID=${CHAT_ID:-}
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[ -n "$SERVERS" ] || { printf >&2 'SERVERS not set\n'; exit 1; }
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# If TOKENS unset, synthesize "-" for each server
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if [ -z "$TOKENS" ]; then
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n=$(printf '%s\n' "$SERVERS" | tr -cd ',' | wc -c | awk '{print $1+1}')
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TOKENS=$(awk -v n="$n" 'BEGIN{for(i=1;i<=n;i++){printf("-"); if(i<n)printf(",")}}')
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fi
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mkdir -p "$STATE_DIR"
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# --- helpers ---
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# get_csv VAR idx -> echo idx-th field (1-based) from CSV string VAR
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get_csv() {
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# shellcheck disable=SC2001
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printf '%s' "$1" | sed 's/,/\n/g' | awk -v n="$2" 'NR==n{print; exit}'
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}
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notify() {
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msg=$1
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if [ -n "$TOKEN" ] && [ -n "$CHAT_ID" ]; then
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curl -sS -m "$TIMEOUT" -X POST "https://api.telegram.org/bot${TOKEN}/sendMessage" \
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-d "chat_id=${CHAT_ID}" \
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--data-urlencode "text=${msg}" >/dev/null || printf >&2 'notify failed: %s\n' "$msg"
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else
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printf >&2 '%s\n' "$msg"
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fi
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}
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sid() { printf '%s' "$1" | cksum | awk '{print $1}'; }
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parse_summary() {
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sed -n 's/.*"summary":{"total":\([0-9][0-9]*\),"ok":\([0-9][0-9]*\)}.*/\1 \2/p'
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}
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list_failures() {
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awk '
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BEGIN{FS="\""; u=""; c=""}
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/"url":/ {u=$4}
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/"code":/ {c=$0; sub(/.*"code":/,"",c); sub(/,.*/,"",c)}
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/"ok":false/ { if(u!=""){ printf "%s(%s) ", u, c; u=""; c="" } }
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'
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}
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# --- main loop ---
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while :; do
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i=1
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while :; do
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srv=$(get_csv "$SERVERS" "$i") || true
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[ -n "${srv:-}" ] || break
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tok=$(get_csv "$TOKENS" "$i") || tok="-"
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url="${srv%/}/status"
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auth_h=""
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[ "${tok}" != "-" ] && [ -n "${tok}" ] && auth_h="-H Authorization: Basic\ $tok"
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tmpb=$(mktemp) || exit 1
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code=$(sh -c "curl -sS -m \"$TIMEOUT\" -w '%{http_code}' -o \"$tmpb\" $auth_h \"$url\"") || code="000"
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body=$(cat "$tmpb"); rm -f "$tmpb"
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ok="down"; tot=0; good=0
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if [ "$code" = "200" ]; then
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s=$(printf '%s' "$body" | parse_summary || true)
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[ -n "$s" ] && { tot=${s%% *}; good=${s#* }; }
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[ "$tot" -eq "$good" ] && ok="up"
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fi
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msg_prefix=$( [ "$ok" = "up" ] && printf 'OK' || printf 'FAIL' )
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fail_list=""
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if [ "$ok" = "down" ] && [ -n "$body" ]; then
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fails=$(printf '%s' "$body" | list_failures | sed 's/[ ]$//')
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[ -n "$fails" ] && fail_list=" — ${fails}"
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fi
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msg=$(printf '%s: %s [%s/%s]%s' "$msg_prefix" "$srv" "$good" "$tot" "$fail_list")
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sfile="${STATE_DIR}/$(sid "$srv").state"
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last=""; [ -f "$sfile" ] && last=$(cat "$sfile")
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cur="${ok}:${good}/${tot}:${code}"
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if [ "$cur" != "$last" ]; then
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notify "$msg"
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printf '%s' "$cur" >"$sfile"
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fi
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i=$((i+1))
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done
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sleep "$POLLING_INTERVAL_SEC"
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done
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