Cache PostgreSQL package downloads

PostgreSQL packages are downloaded from upstream repositories on every
action invocation. These downloads account for a significant portion of
the setup time and are redundant when the package version has not
changed. They are not always reliable either: Chocolatey, for example,
frequently fails to download the PostgreSQL installer. So we better
cache these downloads to make subsequent runs faster and more reliable.

Since package updates retain the same PostgreSQL major version, rotate
cache keys weekly to allow updated packages to be cached for the same
platform and PostgreSQL version.

Author: ikalnytskyi

action.yml

@@ -42,6 +42,22 @@ outputs:
 runs:
   using: composite
   steps:
+    - name: Get current week number
+      id: week
+      run: |
+        echo "value=$(date -u +%Y-%W)" >> "$GITHUB_OUTPUT"
+      shell: bash
+
+    - name: Cache PostgreSQL packages
+      uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9
+      with:
+        path: |
+          ${{ runner.temp }}/packages/postgresql*.deb
+          ${{ runner.temp }}/packages/libpq*.deb
+          ${{ runner.temp }}/packages/postgresql-*.zip
+          ~/Library/Caches/Homebrew/downloads/*--postgresql@*
+        key: postgresql-${{ runner.os }}-${{ runner.arch }}-${{ inputs.postgres-version }}-${{ steps.week.outputs.value }}
+
     - name: Install PostgreSQL
       run: |
         if [[ ! "$INPUT_POSTGRES_VERSION" =~ ^(14|15|16|17|18)$ ]]; then
@@ -64,8 +80,11 @@ runs:
           echo "create_main_cluster = false" | sudo tee \
             /etc/postgresql-common/createcluster.d/50-action-setup-postgres.conf
 
+          mkdir -p "$RUNNER_TEMP/packages"
           sudo apt-get update
-          sudo apt-get -y install postgresql-$INPUT_POSTGRES_VERSION
+          sudo apt-get \
+            -o "Dir::Cache::archives=$RUNNER_TEMP/packages" \
+            -y install postgresql-$INPUT_POSTGRES_VERSION
 
           PG_BINDIR=$("/usr/lib/postgresql/$INPUT_POSTGRES_VERSION/bin/pg_config" --bindir)
           echo "$PG_BINDIR" >> $GITHUB_PATH
@@ -81,28 +100,20 @@ runs:
             echo "$name=" >> $GITHUB_ENV
           done
 
-          # Chocolatey downloads the PostgreSQL installer from
-          # get.enterprisedb.com, which intermittently responds with HTTP 403
-          # and aborts the install. Retry a few times to absorb such transient
-          # download failures.
-          for attempt in 1 2 3; do
-            if choco install postgresql$INPUT_POSTGRES_VERSION \
-              --ia "--enable-components server,commandlinetools --extract-only 1" \
-              --no-progress; then
-              break
-            fi
-
-            if [ "$attempt" -eq 3 ]; then
-              echo "::error::Failed to install PostgreSQL after $attempt attempts."
-              exit 1
-            fi
+          POSTGRES_VERSION=$(choco search postgresql$INPUT_POSTGRES_VERSION \
+            --exact --limit-output | cut -d "|" -f 2 | cut -d "." -f 1,2)
+          POSTGRES_ARCHIVE="$RUNNER_TEMP/packages/postgresql-$POSTGRES_VERSION-1-windows-x64-binaries.zip"
+          POSTGRES_DIR="$RUNNER_TEMP/postgresql"
 
-            echo "::warning::choco install failed (attempt $attempt), retrying in 15s..."
-            sleep 15
-          done
+          if [ ! -f "$POSTGRES_ARCHIVE" ]; then
+            curl --fail --location --retry 3 --retry-all-errors \
+              --output "$POSTGRES_ARCHIVE" \
+              "https://get.enterprisedb.com/postgresql/$(basename "$POSTGRES_ARCHIVE")"
+          fi
+          unzip -q "$POSTGRES_ARCHIVE" -d "$POSTGRES_DIR"
 
-          PG_BINDIR=$("$PROGRAMFILES/PostgreSQL/$INPUT_POSTGRES_VERSION/bin/pg_config.exe" --bindir)
-          PG_LIBDIR=$("$PROGRAMFILES/PostgreSQL/$INPUT_POSTGRES_VERSION/bin/pg_config.exe" --libdir)
+          PG_BINDIR="$POSTGRES_DIR/pgsql/bin"
+          PG_LIBDIR="$POSTGRES_DIR/pgsql/lib"
 
           echo "$PG_BINDIR" >> $GITHUB_PATH
           echo "PQ_LIB_DIR=$PG_LIBDIR" >> $GITHUB_ENV