fix error when non-root user tries to cache latest endpoint, also don't need to re-cache same endpoint

CHANGELOG.md

@@ -1,6 +1,6 @@
 # CHANGELOG
 
-## 2026-06-XX - Tiny Cloud v3.3.3
+## 2026-06-15 - Tiny Cloud v3.3.3
 
 * Support IPv6 and multiple endpoints
   [#68](https://gitlab.alpinelinux.org/alpine/cloud/tiny-cloud/-/work_items/68)
@@ -9,6 +9,10 @@
   routable.  Fixes race condition between `dhcpcd` starting and attempting to
   reach IMDS before routes are resolved.
 
+* Currently the most recent IMDS endpoint that worked is cached, but only if
+  **root** is running `imds`.  We may consider keeping track of this per user
+  in the future
+
 ## 2026-06-08 - Tiny Cloud v3.3.2
 
 * Fixes an autodetect regression introduced in v3.3.1

bin/imds

@@ -120,7 +120,7 @@ _imds_has_route() {
 }
 
 _imds() {
-	local endpoint endpoints routed attempts=1
+	local endpoint endpoints routed attempts=1 cached
 	if [ "$IMDS_ENDPOINT_WAIT_ATTEMPTS" -le 0 ]; then
 		endpoints="$(_imds_endpoints)"
 	fi
@@ -148,7 +148,8 @@ _imds() {
 		wget --quiet --timeout 1 --output-document - \
 			--header "$(_imds_header)" \
 			"http://$endpoint/$IMDS_URI/$1$IMDS_QUERY" && {
-				echo "$endpoint" > "$IMDS_ENDPOINT_CACHE"
+				cached="$(cat "$IMDS_ENDPOINT_CACHE" 2>/dev/null)" || :
+				[ "$endpoint" = "$cached" ] || echo "$endpoint" 2>/dev/null > "$IMDS_ENDPOINT_CACHE" || :
 				return 0
 			}
 	done