Merge pull request #1673 from dagger/extract-yarn-install-into-a-separate-step

Extract yarn install into a separate step

pkg/universe.dagger.io/yarn/test/test.cue

@@ -66,7 +66,7 @@ dagger.#Plan & {
 
 			build: yarn.#Build & {
 				source: common.data
-				container: input: buildImage.output
+				container: #input: buildImage.output
 			}
 		}
 	}

pkg/universe.dagger.io/yarn/yarn.cue

@@ -16,28 +16,26 @@ import (
 	script:   *"build" | string
 }
 
-// Build a Yarn package
+// Run a Yarn command
 #Run: {
-	// Custom name for the build.
+	// Custom name for this command.
-	//   When building different apps in the same plan, assign
+	// Assign an app-specific name if there are multiple apps in the same plan.
-	//   different names for optimal caching.
 	name: string | *""
 
-	// Application source code
+	// App source code
 	source: dagger.#FS
 
-	// working directory to use
+	// Working directory to use
 	cwd: *"." | string
 
-	// Write the contents of `environment` to this file,
+	// Write the contents of `environment` to this file, in the "envfile" format
-	// in the "envfile" format
 	writeEnvFile: string | *""
 
-	// Read build output from this directory
+	// Optional: Read build output from this directory
-	// (path must be relative to working directory)
+	// Must be relative to working directory, cwd
 	buildDir?: string
 
-	// Run this yarn script
+	// Yarn script to run for this command.
 	script: string
 
 	// Fix for shadowing issues
@@ -50,29 +48,56 @@ import (
 	// FIXME: not implemented. Are they needed?
 	secrets: [string]: dagger.#Secret
 
+	container: #input: docker.#Image | *{
 		// FIXME: Yarn's version depends on Alpine's version
 		// Yarn version
 		// yarnVersion: *"=~1.22" | string
-
 		// FIXME: custom base image not supported
-	_buildImage: alpine.#Build & {
+		alpine.#Build & {
 			packages: {
 				bash: {}
 				yarn: {}
 			}
 		}
+	}
 
-	// Run yarn in a docker container
+	_run: docker.#Build & {
-	container: bash.#Run & {
+		steps: [
-		input: *_buildImage.output | docker.#Image
+			container.#input,
 
+			docker.#Copy & {
+				dest:     "/src"
+				contents: source
+			},
+
+			bash.#Run & {
+				// FIXME: move shell script to its own file
+				script: contents: #"""
+					yarn --cwd "$YARN_CWD" install --production false
+					"""#
+
+				mounts: "yarn cache": {
+					dest:     "/cache/yarn"
+					contents: dagger.#CacheDir & {
+						// FIXME: are there character limitations in cache ID?
+						id: "universe.dagger.io/yarn.#Run \(name)"
+					}
+				}
+
+				env: {
+					YARN_CACHE_FOLDER: "/cache/yarn"
+					YARN_CWD:          cwd
+				}
+
+				workdir: "/src"
+			},
+
+			bash.#Run & {
 				// FIXME: move shell script to its own file
 				script: contents: #"""
 					# Create $ENVFILE_NAME file if set
 					[ -n "$ENVFILE_NAME" ] && echo "$ENVFILE" > "$ENVFILE_NAME"
 
-			yarn --cwd "$YARN_CWD" install --production false
-
 					opts=( $(echo $YARN_ARGS) )
 					yarn --cwd "$YARN_CWD" run "$YARN_BUILD_SCRIPT" ${opts[@]}
 					if [ ! -z "${YARN_BUILD_DIRECTORY:-}" ]; then
@@ -82,21 +107,13 @@ import (
 					fi
 					"""#
 
-		mounts: {
+				mounts: "yarn cache": {
-			"yarn cache": {
 					dest:     "/cache/yarn"
 					contents: dagger.#CacheDir & {
 						// FIXME: are there character limitations in cache ID?
-					id: "universe.dagger.io/yarn.#Build \(name)"
+						id: "universe.dagger.io/yarn.#Run \(name)"
 					}
 				}
-			"package source": {
-				dest:     "/src"
-				contents: source
-			}
-		}
-
-		export: directories: "/build": _
 
 				env: {
 					YARN_BUILD_SCRIPT: yarnScript
@@ -113,8 +130,15 @@ import (
 				}
 
 				workdir: "/src"
+			},
+		]
 	}
 
-	// The final contents of the package after build
+	// The final contents of the package after run
-	output: container.export.directories."/build"
+	_output: dagger.#Subdir & {
+		input: _run.output.rootfs
+		path:  "/build"
+	}
+
+	output: _output.output
 }