docker.#Build: support for nested builds

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

pkg/universe.dagger.io/docker/build.cue

@@ -16,7 +16,12 @@ import (
 			"\(idx)": step & {
 				// connect input to previous output
 				if idx > 0 {
-					input: _dag["\(idx-1)"].output
+					// FIXME: the intermediary `output` is needed because of a possible CUE bug.
+					// `._dag."0".output: 1 errors in empty disjunction::`
+					// See: https://github.com/cue-lang/cue/issues/1446
+					// input: _dag["\(idx-1)"].output
+					_output: _dag["\(idx-1)"].output
+					input:   _output
 				}
 			}
 		}

pkg/universe.dagger.io/docker/test/bash/bash.cue

@@ -1,15 +0,0 @@
-package docker
-
-cmd: #Command & {
-	script: "echo hello world"
-	exec: {
-		name: "/bin/bash"
-		flags: {
-			"-c":          script
-			"--noprofile": true
-			"--norc":      true
-			"-e":          true
-			"-o":          "pipefail"
-		}
-	}
-}

pkg/universe.dagger.io/docker/test/build/build.cue

@@ -1,65 +0,0 @@
-package docker
-
-import (
-	"dagger.io/dagger"
-	"universe.dagger.io/nginx"
-)
-
-tests: {
-	"set config manually": build: #Build & {
-		steps: [{
-			output: #Image & {
-				config: user: "foo"
-			}
-		}]
-	}
-
-	//    - import nginx base
-	//    - copy app directory into /usr/share/nginx/html
-	"build static web server": {
-		source: dagger.#FS
-
-		build: #Build & {
-			steps: [
-				nginx.#Build & {
-					flavor: "alpine"
-				},
-				{
-					// Custom step to watermark the image
-					input:  _
-					output: input & {
-						config: user: "42"
-					}
-				},
-				#Copy & {
-					contents: source
-					dest:     "/usr/share/nginx/html"
-				},
-			]
-		}
-
-		image: build.output
-		// Assert:
-		image: config: user: "42"
-	}
-
-	"Run multiple commands": {
-		build: #Build & {
-			steps: [
-				#Pull & {
-					source: "alpine"
-				},
-				#Run & {
-					script: "echo A > /A.txt"
-				},
-				#Run & {
-					script: "echo B > /B.txt"
-				},
-				#Run & {
-					script: "echo C > /C.txt"
-				},
-			]
-		}
-		result: build.output
-	}
-}

pkg/universe.dagger.io/docker/test/docker.bats

@@ -0,0 +1,13 @@
+setup() {
+    load '../../bats_helpers'
+
+    common_setup
+}
+
+@test "docker.#Build" {
+    dagger up ./nested-build-test.cue
+
+    # FIXME: this is currently broken
+    run dagger up ./multi-nested-build-test.cue
+    assert_failure
+}

pkg/universe.dagger.io/docker/test/multi-nested-build-test.cue

@@ -0,0 +1,33 @@
+package docker
+
+import (
+	"dagger.io/dagger"
+	"universe.dagger.io/docker"
+)
+
+dagger.#Plan & {
+	actions: build: docker.#Build & {
+		steps: [
+			docker.#Build & {
+				steps: [
+					docker.#Build & {
+						steps: [
+							docker.#Pull & {
+								source: "alpine"
+							},
+							docker.#Run & {
+								cmd: name: "ls"
+							},
+						]
+					},
+					docker.#Run & {
+						cmd: name: "ls"
+					},
+				]
+			},
+			docker.#Run & {
+				cmd: name: "ls"
+			},
+		]
+	}
+}

pkg/universe.dagger.io/docker/test/nested-build-test.cue

@@ -0,0 +1,26 @@
+package docker
+
+import (
+	"dagger.io/dagger"
+	"universe.dagger.io/docker"
+)
+
+dagger.#Plan & {
+	actions: build: docker.#Build & {
+		steps: [
+			docker.#Build & {
+				steps: [
+					docker.#Pull & {
+						source: "alpine"
+					},
+					docker.#Run & {
+						cmd: name: "ls"
+					},
+				]
+			},
+			docker.#Run & {
+				cmd: name: "ls"
+			},
+		]
+	}
+}