Add shard caching to CI

.github/workflows/ci.yml

@@ -10,39 +10,48 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       
-      - name: Install Crystal
-        uses: oprypin/install-crystal@v1.2.4
-      
-      # - name: Cache dependencies
+      # - name: Find out latest Crystal version
+      #   run: |
+      #     crystal_latest=$(curl -ILs -o /dev/null -w %{url_effective} https://github.com/crystal-lang/crystal/releases/latest | grep -o '[^/]*$')
+      #     echo "crystal_latest=$crystal_latest" >> $GITHUB_ENV
+      #     echo $crystal_latest
+      #
+      # - name: Cache Crystal
       #   uses: actions/cache@v2
       #   with:
-      #     path: ./lib
-      #     key: shards-${{ hashFiles('shard.lock') }} # shard.lock isn't tracked atm
+      #     path: ./crystal-bin
+      #     key: crystal-${{ env.crystal_latest }}
+      #
+      # - name: Add custom Crystal dir to path
+      #   run: echo "./crystal-bin" >> $GITHUB_PATH
+      #
+      # - name: Find out installed Crystal version
+      #   run: |
+      #     if ! [ -x "$(command -v crystal)" ]; then
+      #       crystal_installed="none"
+      #     else
+      #       crystal_installed=$(crystal version | grep Crystal | awk '{print $2}')
+      #     fi
+      #     echo "crystal_installed=$crystal_installed" >> $GITHUB_ENV
+      #     echo $crystal_installed
       
-      # Docs at https://crystal-lang.org/reference/the_shards_command
-      #
-      # `shards install`
-      #
-      # Resolves and installs dependencies into the lib folder. If not already present, generates a shard.lock
-      # file from resolved dependencies, locking version numbers or Git commits.
-      # Reads and enforces locked versions and commits if a shard.lock file is present. The install command may
-      # fail if a locked version doesn't match a requirement, but may succeed if a new dependency was added, as
-      # long as it doesn't generate a conflict, thus generating a new shard.lock file.
-      #
-      # `shards update`
-      #
-      # Resolves and updates all dependencies into the lib folder again, whatever the locked versions and
-      # commits in the shard.lock file. Eventually generates a new shard.lock file.
-      #
-      # --------------------------------------------------------------------------------
-      #
-      # running either `shards install` or `shards update` without a `shard.lock` file does the same thing,
-      # downloading shards into the `lib` folder and writing a `shard.lock` file
-      #
-      # if there is a `shard.lock` file `shards install` installs the versions from the lock file while
-      # `shards update` does a `shards install` that pretends there isn't a lock file present
-      - name: Update and install shards
-        run: shards update
+      - name: Install Crystal
+        uses: oprypin/install-crystal@v1.2.4
+        # if: env.crystal_installed != env.crystal_latest
+        # with:
+        #   destination: ./crystal-bin
+
+      - name: Cache Shards
+        uses: actions/cache@v2
+        with:
+          path: ./lib
+          key: shards-${{ hashFiles('shard.lock') }}
+      
+      - name: Install Shards
+        run: |
+          if ! shards check; then
+            shards install
+          fi
       
       - name: Run tests
         run: crystal spec