diff --git a/pkg/universe.dagger.io/cue.mod/pkg/.gitignore b/pkg/universe.dagger.io/cue.mod/pkg/.gitignore
new file mode 100644
index 00000000..331f139d
--- /dev/null
+++ b/pkg/universe.dagger.io/cue.mod/pkg/.gitignore
@@ -0,0 +1,5 @@
+# generated by dagger
+dagger.lock
+alpha.dagger.io
+dagger.io
+universe.dagger.io
\ No newline at end of file
diff --git a/pkg/universe.dagger.io/docker/build.cue b/pkg/universe.dagger.io/docker/build.cue
index 9c272b28..162315af 100644
--- a/pkg/universe.dagger.io/docker/build.cue
+++ b/pkg/universe.dagger.io/docker/build.cue
@@ -61,18 +61,43 @@ import (
 
 // Build step that executes a Dockerfile
 #Dockerfile: {
-	// Source directory
 	source: dagger.#FS
 
-	// FIXME: not yet implemented
-	*{
-		// Look for Dockerfile in source at default path
-		path: "Dockerfile"
+	// Dockerfile definition or path into source
+	dockerfile: *{
+		path: string | *"Dockerfile"
 	} | {
-		// Look for Dockerfile in source at a custom path
-		path: string
-	} | {
-		// Custom dockerfile  contents
 		contents: string
 	}
+
+	// Registry authentication
+	// Key must be registry address
+	auth: [registry=string]: {
+		username: string
+		secret:   dagger.#Secret
+	}
+
+	platforms: [...string]
+	target?: string
+	buildArg: [string]: string
+	label: [string]:    string
+	hosts: [string]:    string
+
+	_build: dagger.#Dockerfile & {
+		"source":     source
+		"auth":       auth
+		"dockerfile": dockerfile
+		"platforms":  platforms
+		if target != _|_ {
+			"target": target
+		}
+		"buildArg": buildArg
+		"label":    label
+		"hosts":    hosts
+	}
+
+	output: #Image & {
+		rootfs: _build.output
+		config: _build.config
+	}
 }
diff --git a/pkg/universe.dagger.io/docker/test/dockerfile.cue b/pkg/universe.dagger.io/docker/test/dockerfile.cue
new file mode 100644
index 00000000..259a86b2
--- /dev/null
+++ b/pkg/universe.dagger.io/docker/test/dockerfile.cue
@@ -0,0 +1,69 @@
+package docker
+
+import (
+	"dagger.io/dagger"
+	"universe.dagger.io/docker"
+)
+
+dagger.#Plan & {
+	client: filesystem: "./testdata": read: contents: dagger.#FS
+
+	actions: test: dockerfile: {
+		simple: {
+			build: docker.#Build & {
+				steps: [
+					docker.#Dockerfile & {
+						source: dagger.#Scratch
+						dockerfile: contents: """
+							FROM alpine:3.15
+							
+							RUN echo -n hello world >> /test.txt
+						"""
+					},
+					docker.#Run & {
+						command: {
+							name: "/bin/sh"
+							args: ["-c", """
+						  # Verify that docker.#Dockerfile correctly connect output
+						  # into other steps
+							grep -q "hello world" /test.txt
+						"""]
+						}
+					},
+				]
+			}
+
+			verify: dagger.#ReadFile & {
+				input: build.output.rootfs
+				path:  "/test.txt"
+			} & {
+				contents: "hello world"
+			}
+		}
+
+		withInput: {
+			build: docker.#Build & {
+				steps: [
+					docker.#Dockerfile & {
+						source: client.filesystem."./testdata".read.contents
+					},
+					docker.#Run & {
+						command: {
+							name: "/bin/sh"
+							args: ["-c", """
+							hello >> /test.txt
+						"""]
+						}
+					},
+				]
+			}
+
+			verify: dagger.#ReadFile & {
+				input: build.output.rootfs
+				path:  "/test.txt"
+			} & {
+				contents: "hello world"
+			}
+		}
+	}
+}
diff --git a/pkg/universe.dagger.io/docker/test/test.bats b/pkg/universe.dagger.io/docker/test/test.bats
index f95740d7..bebf70cb 100644
--- a/pkg/universe.dagger.io/docker/test/test.bats
+++ b/pkg/universe.dagger.io/docker/test/test.bats
@@ -5,5 +5,8 @@ setup() {
 }
 
 @test "docker" {
-    dagger "do" -p ./ test
+    dagger "do" -p ./build.cue test
+    dagger "do" -p ./dockerfile.cue test
+    dagger "do" -p ./run.cue test
+    dagger "do" -p ./image.cue test
 }
diff --git a/pkg/universe.dagger.io/docker/test/testdata/Dockerfile b/pkg/universe.dagger.io/docker/test/testdata/Dockerfile
new file mode 100644
index 00000000..430a482a
--- /dev/null
+++ b/pkg/universe.dagger.io/docker/test/testdata/Dockerfile
@@ -0,0 +1,19 @@
+###
+# STAGE: builder
+# Build a simple go program
+# GO TO STAGE: app
+###
+FROM golang:1.17-alpine as builder
+
+WORKDIR /app
+
+COPY go.mod .
+COPY main.go .
+
+RUN go build -o hello main.go
+
+FROM alpine:3.15@sha256:21a3deaa0d32a8057914f36584b5288d2e5ecc984380bc0118285c70fa8c9300
+
+COPY --from=builder /app/hello /bin/hello
+
+ENTRYPOINT ["hello"]
\ No newline at end of file
diff --git a/pkg/universe.dagger.io/docker/test/testdata/go.mod b/pkg/universe.dagger.io/docker/test/testdata/go.mod
new file mode 100644
index 00000000..9bacf229
--- /dev/null
+++ b/pkg/universe.dagger.io/docker/test/testdata/go.mod
@@ -0,0 +1,3 @@
+module test.com
+
+go 1.17
diff --git a/pkg/universe.dagger.io/docker/test/testdata/main.go b/pkg/universe.dagger.io/docker/test/testdata/main.go
new file mode 100644
index 00000000..75b323ab
--- /dev/null
+++ b/pkg/universe.dagger.io/docker/test/testdata/main.go
@@ -0,0 +1,7 @@
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Printf("hello world")
+}