label-kernel: make it reusable

In some cases it might be handy to quickly smoke test certain types of
changes, where it usually doesn't make sense to build everything, so
lets allow that with reusable label-kernel workflow, which can be easily
reusable by just passing target/subtarget/testing inputs.

References: openwrt/openwrt#16784
Signed-off-by: Petr Štetiar <ynezz@true.cz>

Author: ynezz

.github/workflows/label-kernel.yml

@@ -3,10 +3,17 @@
 name: Build kernel and check patches for target specified in labels
 on:
   workflow_call:
+    inputs:
+      target:
+        type: string
+      subtarget:
+        type: string
+      testing:
+        type: boolean
 
 jobs:
   set_target:
-    if: startsWith(github.event.label.name, 'ci:kernel:')
+    if: startsWith(github.event.label.name, 'ci:kernel:') || inputs.target != ''
     name: Set target
     runs-on: ubuntu-latest
     outputs:
@@ -22,9 +29,30 @@ jobs:
         env:
           CI_EVENT_LABEL_NAME: ${{ github.event.label.name }}
         run: |
-          echo "$CI_EVENT_LABEL_NAME" | sed -n 's/ci:kernel:\([^:]*\):\([^:]*\):*\([^:]*\)$/target=\1/p' | tee --append $GITHUB_OUTPUT
-          echo "$CI_EVENT_LABEL_NAME" | sed -n 's/ci:kernel:\([^:]*\):\([^:]*\):*\([^:]*\)$/subtarget=\2/p' | tee --append $GITHUB_OUTPUT
-          echo "$CI_EVENT_LABEL_NAME" | sed -n 's/ci:kernel:\([^:]*\):\([^:]*\):*\([^:]*\)$/testing=\3/p' | tee --append $GITHUB_OUTPUT
+          if [ -n "${{ inputs.target}}" ]; then
+            target="${{ inputs.target }}"
+          else
+            target=$(echo "$CI_EVENT_LABEL_NAME" | sed -n 's/ci:kernel:\([^:]*\):\([^:]*\):*\([^:]*\)$/\1/p')
+          fi
+
+          if [ -n "${{ inputs.subtarget}}" ]; then
+            subtarget="${{ inputs.subtarget }}"
+          else
+            subtarget=$(echo "$CI_EVENT_LABEL_NAME" | sed -n 's/ci:kernel:\([^:]*\):\([^:]*\):*\([^:]*\)$/\2/p')
+          fi
+
+          if [ -n "${{ inputs.testing}}" ]; then
+            testing="${{ inputs.testing }}"
+          else
+            testing=$(echo "$CI_EVENT_LABEL_NAME" | sed -n 's/ci:kernel:\([^:]*\):\([^:]*\):*\([^:]*\)$/\3/p')
+          fi
+
+          echo "Setting target as $target, subtarget as $subtarget, testing as $testing"
+          {
+            echo "target=$target"
+            echo "subtarget=$subtarget"
+            echo "testing=$testing"
+          } >> "$GITHUB_OUTPUT"
 
       - name: Set targets
         id: set_target