host-metrics: entrypoint + offline tests
Add telegraf-entrypoint.sh to render telegraf.conf from the template (replacing @@HOST_TAG_BLOCK@@ and @@ZFS_BLOCK@@ markers via awk) and exec telegraf. Add test-telegraf-entrypoint.sh with 8 offline tests (10 assertions) covering marker substitution and required-env validation. Fix run() stderr redirect from >/dev/null 2>&1 to >/dev/null so that entrypoint error output reaches the T6-T8 assertion captures. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>pull/753/head
Prathamesh Musale
parent
f5adcfc77e
commit
f898d65983
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@ -0,0 +1,68 @@
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#!/bin/sh
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# host-metrics telegraf-entrypoint.sh
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# Render telegraf.conf from telegraf.conf.tpl, then exec telegraf.
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#
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# Substitutions performed here (by awk):
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# @@HOST_TAG_BLOCK@@ -> "[global_tags]\n host = \"$HOST_TAG\"" if set, else empty.
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# @@ZFS_BLOCK@@ -> "[[inputs.zfs]]\n poolMetrics = true" if COLLECT_ZFS=true, else empty.
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#
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# Variables of the form ${VAR} in the template (INFLUXDB_URL, INFLUXDB_DB,
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# INFLUXDB_USER, INFLUXDB_PASSWORD, COLLECT_INTERVAL) are resolved by
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# telegraf's own env-var substitution at config-load time and are NOT
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# touched by this script.
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#
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# TELEGRAF_CONF_DIR overrides the conf directory for tests; defaults to
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# /etc/telegraf which is the standard path inside the official image.
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set -eu
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CONF_DIR="${TELEGRAF_CONF_DIR:-/etc/telegraf}"
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TPL="$CONF_DIR/telegraf.conf.tpl"
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OUT="$CONF_DIR/telegraf.conf"
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# Fail-fast required env. Empty string counts as missing -- a half-rendered
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# conf or a noisy telegraf auth error is worse than a clear startup failure.
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for v in INFLUXDB_URL INFLUXDB_USER INFLUXDB_PASSWORD; do
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eval val=\${$v:-}
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if [ -z "$val" ]; then
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echo "FATAL: $v is required but empty" >&2
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exit 1
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fi
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done
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# Apply defaults for optional vars.
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: "${INFLUXDB_DB:=host_metrics}"
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: "${COLLECT_INTERVAL:=10s}"
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: "${HOST_TAG:=}"
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: "${COLLECT_ZFS:=false}"
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# Build the marker substitutions. Use printf for the newline so the
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# rendered block lands on its own line.
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if [ -n "$HOST_TAG" ]; then
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HOST_TAG_BLOCK=$(printf '[global_tags]\n host = "%s"' "$HOST_TAG")
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else
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HOST_TAG_BLOCK=""
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fi
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if [ "$COLLECT_ZFS" = "true" ]; then
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ZFS_BLOCK=$(printf '[[inputs.zfs]]\n poolMetrics = true')
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else
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ZFS_BLOCK=""
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fi
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# Export telegraf hostfs envs so /proc, /sys, and root come from the
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# bind-mount under /hostfs (set in compose).
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export HOST_PROC=/hostfs/proc
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export HOST_SYS=/hostfs/sys
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export HOST_MOUNT_PREFIX=/hostfs
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# Render with awk: handles multi-line replacement values cleanly,
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# avoids sed's newline-in-replacement portability quirks across BusyBox /
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# GNU / BSD sed.
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awk -v ht="$HOST_TAG_BLOCK" -v zb="$ZFS_BLOCK" '
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{ gsub(/@@HOST_TAG_BLOCK@@/, ht);
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gsub(/@@ZFS_BLOCK@@/, zb);
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print }
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' "$TPL" > "$OUT"
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exec telegraf --config "$OUT"
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@ -0,0 +1,121 @@
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#!/bin/sh
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# Offline tests for host-metrics telegraf-entrypoint.sh.
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# Stubs telegraf and envsubst's downstream consumer; no telegraf binary needed.
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set -eu
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SCRIPT_DIR=$(cd "$(dirname "$0")" && pwd)
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ENTRYPOINT="$SCRIPT_DIR/telegraf-entrypoint.sh"
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[ -x "$ENTRYPOINT" ] || { echo "FATAL: $ENTRYPOINT not executable"; exit 2; }
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TMP=$(mktemp -d)
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trap 'rm -rf "$TMP"' EXIT
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mkdir -p "$TMP/bin" "$TMP/etc/telegraf"
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# Stub telegraf so `exec telegraf` is a no-op.
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cat > "$TMP/bin/telegraf" <<'EOF'
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#!/bin/sh
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exit 0
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EOF
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chmod +x "$TMP/bin/telegraf"
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# Minimal template that exercises both markers.
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cat > "$TMP/etc/telegraf/telegraf.conf.tpl" <<'EOF'
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@@HOST_TAG_BLOCK@@
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[agent]
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interval = "${COLLECT_INTERVAL}"
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[[outputs.influxdb]]
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urls = ["${INFLUXDB_URL}"]
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@@ZFS_BLOCK@@
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EOF
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PASS=0
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FAIL=0
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# run sets required env defaults, then layers caller env on top.
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run() {
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env PATH="$TMP/bin:$PATH" \
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TELEGRAF_CONF_DIR="$TMP/etc/telegraf" \
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INFLUXDB_URL="${INFLUXDB_URL-http://example/}" \
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INFLUXDB_USER="${INFLUXDB_USER-writer}" \
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INFLUXDB_PASSWORD="${INFLUXDB_PASSWORD-secret}" \
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INFLUXDB_DB="${INFLUXDB_DB-host_metrics}" \
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COLLECT_INTERVAL="${COLLECT_INTERVAL-10s}" \
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HOST_TAG="${HOST_TAG-}" \
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COLLECT_ZFS="${COLLECT_ZFS-false}" \
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sh "$ENTRYPOINT" >/dev/null
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rc=$?
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[ -f "$TMP/etc/telegraf/telegraf.conf" ] && cat "$TMP/etc/telegraf/telegraf.conf"
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return $rc
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}
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assert_grep() {
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name=$1; actual=$2; pattern=$3
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if printf '%s' "$actual" | grep -qE "$pattern"; then
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echo "PASS: $name"; PASS=$((PASS + 1))
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else
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echo "FAIL: $name"
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echo " expected pattern: $pattern"
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echo " actual: $actual"
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FAIL=$((FAIL + 1))
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fi
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}
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assert_not_grep() {
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name=$1; actual=$2; pattern=$3
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if printf '%s' "$actual" | grep -qE "$pattern"; then
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echo "FAIL: $name (matched pattern $pattern)"; FAIL=$((FAIL + 1))
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else
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echo "PASS: $name"; PASS=$((PASS + 1))
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fi
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}
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# T1: HOST_TAG unset -> no [global_tags] block emitted
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out=$(HOST_TAG="" run)
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assert_not_grep "T1: HOST_TAG empty -> no global_tags" "$out" '^\[global_tags\]'
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# T2: HOST_TAG set -> [global_tags] block with host = "<value>"
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out=$(HOST_TAG="validator-1" run)
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assert_grep "T2: HOST_TAG set -> [global_tags] block" "$out" '^\[global_tags\]'
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assert_grep "T2: HOST_TAG set -> host = \"validator-1\"" "$out" 'host = "validator-1"'
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# T3: COLLECT_ZFS=true -> [[inputs.zfs]] block present
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out=$(COLLECT_ZFS="true" run)
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assert_grep "T3: COLLECT_ZFS true -> inputs.zfs block" "$out" '\[\[inputs\.zfs\]\]'
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# T4: COLLECT_ZFS=false -> no inputs.zfs block
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out=$(COLLECT_ZFS="false" run)
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assert_not_grep "T4: COLLECT_ZFS false -> no inputs.zfs" "$out" '\[\[inputs\.zfs\]\]'
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# T5: markers fully removed even when block bodies are empty
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out=$(HOST_TAG="" COLLECT_ZFS="false" run)
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assert_not_grep "T5: no leftover @@HOST_TAG_BLOCK@@" "$out" '@@HOST_TAG_BLOCK@@'
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assert_not_grep "T5: no leftover @@ZFS_BLOCK@@" "$out" '@@ZFS_BLOCK@@'
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# T6: missing INFLUXDB_URL -> exit non-zero, error on stderr
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rc=0
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INFLUXDB_URL="" run 2>"$TMP/err" || rc=$?
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[ "$rc" -ne 0 ] && grep -q INFLUXDB_URL "$TMP/err" \
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&& { echo "PASS: T6: missing INFLUXDB_URL -> error"; PASS=$((PASS + 1)); } \
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|| { echo "FAIL: T6: missing INFLUXDB_URL handling (rc=$rc)"; FAIL=$((FAIL + 1)); }
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# T7: missing INFLUXDB_USER -> exit non-zero
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rc=0
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INFLUXDB_USER="" run 2>"$TMP/err" || rc=$?
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[ "$rc" -ne 0 ] && grep -q INFLUXDB_USER "$TMP/err" \
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&& { echo "PASS: T7: missing INFLUXDB_USER -> error"; PASS=$((PASS + 1)); } \
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|| { echo "FAIL: T7: missing INFLUXDB_USER handling (rc=$rc)"; FAIL=$((FAIL + 1)); }
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# T8: missing INFLUXDB_PASSWORD -> exit non-zero
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rc=0
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INFLUXDB_PASSWORD="" run 2>"$TMP/err" || rc=$?
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[ "$rc" -ne 0 ] && grep -q INFLUXDB_PASSWORD "$TMP/err" \
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&& { echo "PASS: T8: missing INFLUXDB_PASSWORD -> error"; PASS=$((PASS + 1)); } \
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|| { echo "FAIL: T8: missing INFLUXDB_PASSWORD handling (rc=$rc)"; FAIL=$((FAIL + 1)); }
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echo
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echo "Results: $PASS passed, $FAIL failed"
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[ "$FAIL" = "0" ]
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