ci: build one SDK container per target instead of per architecture

Each target has unique base packages, so SDKs need to be built per
target. The first target for each architecture also gets an arch-based
tag as a convenience default.

Tags use dashes instead of slashes (e.g. ath79-generic not ath79/generic)
since Docker tags cannot contain slashes.

Author: aparcar

.github/workflows/containers.yml

@@ -117,21 +117,28 @@ jobs:
           echo -e "\n---- rootfs ----\n"
           echo "rootfs=$JSON_ROOTFS" >> "$GITHUB_OUTPUT"
 
-          # sdks
+          # sdks - one per target, first target per arch also gets the arch tag
+          declare -A ARCH_SEEN
           JSON='['
           FIRST=1
 
           while read -r line;
           do
-            ARCH=$(echo "$line" | cut -d " " -f 1)
-            [ -z "$TARGET_FILTER" ] && TARGET=$(echo "$line" | cut -d " " -f 2) || TARGET="$TARGET_FILTER"
-            TARGETS=$(echo "$line" | cut -d " " -f 2- | sed -e 's/ /\\n/g')
+            TARGET=$(echo "$line" | cut -d " " -f 1)
+            ARCH=$(echo "$line" | cut -d " " -f 2)
+            TARGET_TAG="${TARGET//\//-}"
+
+            TAGS="$TARGET_TAG"
+            if [ -z "${ARCH_SEEN[$ARCH]+x}" ]; then
+              TAGS="$TARGET_TAG\n$ARCH"
+              ARCH_SEEN[$ARCH]=1
+            fi
 
             [[ $FIRST -ne 1 ]] && JSON="$JSON"','
             FIRST=0
 
-            JSON="$JSON"'{"arch":"'"$ARCH"'","target":"'"$TARGET"'","tags":"'"$ARCH"'\n'"$TARGETS"'"}'
-          done <<< $(perl ./scripts/dump-target-info.pl architectures 2>/dev/null | ([[ -n "$TARGET_FILTER" ]] && grep -w "$TARGET_FILTER" || cat))
+            JSON="$JSON"'{"target":"'"$TARGET"'","tags":"'"$TAGS"'"}'
+          done <<< $(perl ./scripts/dump-target-info.pl targets 2>/dev/null | ([[ -n "$TARGET_FILTER" ]] && grep -w "$TARGET_FILTER" || cat))
 
           JSON='{"include":'"$JSON"']}'
           echo -e "\n---- sdks ----\n"