initial commit

Author: klpx

.github/workflows/test.yml

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+on:
+  push:
+
+jobs:
+  case-basic:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: ./
+        with:
+          path: ./tests
+          values: |
+            values.yml
+            values-override.yml
+          output: |
+            app_name = .appName
+            host = .nginx.host

.gitignore

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+/.idea/

action.yaml

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+name: Read Helm Values
+description:
+  Given list of values.yaml files, it will read specified variables from the merged result.
+  
+  Because of dynamic nature of output variables, they are written to $GITHUB_OUTPUT.
+  So no output is defined in this action
+inputs:
+  path:
+    description: Base directory for values files
+    required: false
+    default: '.'
+  values:
+    description: List of values files, separated by newline
+    required: true
+  output:
+    description: Key-values list of variables to read, format is `key=.yq.expression`, each pair is on new line
+    required: true
+runs:
+  using: composite
+  steps:
+    - name: Install yq
+      shell: bash
+      run: |
+        set -e
+        if ! command -v yq &> /dev/null; then
+          wget https://github.com/mikefarah/yq/releases/download/v4.46.1/yq_linux_amd64 -O /usr/local/bin/yq
+          chmod +x /usr/local/bin/yq
+        fi
+
+    - name: Extract Helm values
+      id: extract
+      shell: bash
+      run: |
+        EXPRS=()
+        while IFS= read -r line; do
+          [[ -z "$line" ]] && continue
+          EXPRS+=("$line")
+        done <<< "${{ inputs.output }}"
+        
+        ${{ github.action_path }}/read-values.bash <<< "${{ inputs.values_files }}" >> "$GITHUB_OUTPUT"

read-values.bash

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+#!/usr/bin/env bash
+set -euo pipefail
+shopt -s extglob
+
+FILES=()
+while IFS= read -r line; do
+  [[ -z "$line" ]] && continue
+  FILES+=("$line")
+done
+if [ ${#FILES[@]} -eq 0 ]; then
+  echo "Error: No values files provided" >&2
+  exit 1
+fi
+
+MERGED=$(yq eval '.' "${FILES[0]}")
+
+# Merge each subsequent file
+for ((i=1; i<${#FILES[@]}; i++)); do
+  MERGED=$(echo "$MERGED" | yq eval-all 'select(fileIndex == 0) * select(fileIndex == 1)' - "${FILES[i]}")
+done
+
+
+# Each argument format:
+#   key = .yq.expression (spaces around '=' are optional)
+
+for out in "$@"; do
+  [[ -z "$out" ]] && continue
+
+  IFS='=' read -r KEY EXPR <<< "$out"
+
+  # trim surronding whitespace
+  KEY="${KEY##+([[:space:]])}"
+  KEY="${KEY%%+([[:space:]])}"
+  EXPR="${EXPR##+([[:space:]])}"
+  EXPR="${EXPR%%+([[:space:]])}"
+
+  VALUE=$(echo "$MERGED" | yq eval "$EXPR" -)
+  echo "${KEY}=${VALUE}"
+done

tests/basic/values-override.yml

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+appName: default
+
+nginx:
+  host: ton.org

tests/basic/values.yml

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+appName: default
+
+nginx:
+  host: example.org
+