Add incremental dockerfiles

04-building-container-images/sample-app/api-golang/.dockerignore

@@ -0,0 +1,3 @@
+Makefile
+README.md
+Dockerfile*

04-building-container-images/sample-app/api-golang/Dockerfile

@@ -1,19 +0,0 @@
-# syntax=docker/dockerfile:1
-
-# Alpine is chosen for its small footprint
-# compared to Ubuntu
-FROM golang:1.19-alpine
-
-WORKDIR /app
-
-# Download necessary Go modules
-COPY go.mod ./
-COPY go.sum ./
-
-RUN go mod download
-
-COPY . .
-
-CMD ["go", "run", "./main.go"]
-
-# TODO use best practices: https://snyk.io/blog/containerizing-go-applications-with-docker/

04-building-container-images/sample-app/api-golang/Dockerfile.0

@@ -0,0 +1,9 @@
+FROM golang
+
+WORKDIR /app 
+
+COPY . .
+
+RUN go mod download
+
+CMD ["go", "run", "./main.go"]

04-building-container-images/sample-app/api-golang/Dockerfile.1

@@ -0,0 +1,11 @@
+# Pin specific version for stability
+# Use alpine for reduced image size
+FROM golang:1.19-alpine
+
+WORKDIR /app 
+
+COPY . .
+
+RUN go mod download
+
+CMD ["go", "run", "./main.go"]

04-building-container-images/sample-app/api-golang/Dockerfile.2

@@ -0,0 +1,14 @@
+# Pin specific version for stability
+# Use alpine for reduced image size
+FROM golang:1.19-alpine
+
+WORKDIR /app 
+
+COPY . .
+
+RUN go mod download
+
+# Compile application during build rather than at runtime
+RUN go build -o api-golang
+
+CMD ["./api-golang"]

04-building-container-images/sample-app/api-golang/Dockerfile.3

@@ -0,0 +1,17 @@
+# Pin specific version for stability
+# Use alpine for reduced image size
+FROM golang:1.19-alpine
+
+WORKDIR /app 
+
+# Copy only files required to install dependencies (better layer caching)
+COPY go.mod go.sum ./
+
+RUN go mod download
+
+COPY . .
+
+# Compile application during build rather than at runtime
+RUN go build -o api-golang
+
+CMD ["./api-golang"]

04-building-container-images/sample-app/api-golang/Dockerfile.4

@@ -0,0 +1,29 @@
+# Pin specific version for stability
+# Use separate stage for building image
+# Use debian for easier build utilities
+FROM golang:1.19-bullseye AS build
+
+WORKDIR /app 
+
+# Copy only files required to install dependencies (better layer caching)
+COPY go.mod go.sum ./
+
+RUN go mod download
+
+COPY . .
+
+# Compile application during build rather than at runtime
+# Add -w and -s flags to 
+RUN go build \
+  -ldflags="-linkmode external -extldflags -static" \
+  -o api-golang
+
+# Use separate stage for deployable image
+FROM scratch
+
+WORKDIR /
+
+# Copy the binary from the build stage
+COPY --from=build /app/api-golang api-golang
+
+CMD ["/api-golang"]

04-building-container-images/sample-app/api-golang/Dockerfile.5

@@ -0,0 +1,35 @@
+# Pin specific version for stability
+# Use separate stage for building image
+# Use debian for easier build utilities
+FROM golang:1.19-bullseye AS build
+
+WORKDIR /app 
+
+# Copy only files required to install dependencies (better layer caching)
+COPY go.mod go.sum ./
+
+RUN go mod download
+
+COPY . .
+
+# Compile application during build rather than at runtime
+# Add flags to statically link binary
+RUN go build \
+  -ldflags="-linkmode external -extldflags -static" \
+  -o api-golang
+
+# Use separate stage for deployable image
+FROM scratch
+
+# Set gin mode
+ENV GIN_MODE=release
+
+WORKDIR /
+
+# Copy the binary from the build stage
+COPY --from=build /app/api-golang api-golang
+
+# Indicate expected port
+EXPOSE 8080
+
+CMD ["/api-golang"]

04-building-container-images/sample-app/api-golang/Dockerfile.6

@@ -0,0 +1,47 @@
+# Pin specific version for stability
+# Use separate stage for building image
+# Use debian for easier build utilities
+FROM golang:1.19-bullseye AS build
+
+# Add non root user
+RUN useradd -u 1001 nonroot
+
+WORKDIR /app 
+
+# Copy only files required to install dependencies (better layer caching)
+COPY go.mod go.sum ./
+
+# Use cache mount to speed up install of existing dependencies
+RUN --mount=type=cache,target=/go/pkg/mod \
+  --mount=type=cache,target=/root/.cache/go-build \
+  go mod download
+
+COPY . .
+
+# Compile application during build rather than at runtime
+# Add flags to statically link binary
+RUN go build \
+  -ldflags="-linkmode external -extldflags -static" \
+  -o api-golang
+
+# Use separate stage for deployable image
+FROM scratch
+
+# Set gin mode
+ENV GIN_MODE=release
+
+WORKDIR /
+
+# Copy the passwd file
+COPY --from=build /etc/passwd /etc/passwd
+
+# Copy the binary from the build stage
+COPY --from=build /app/api-golang api-golang
+
+# Use nonroot user
+USER nonroot
+
+# Indicate expected port
+EXPOSE 8080
+
+CMD ["/api-golang"]

04-building-container-images/sample-app/api-golang/Makefile

@@ -1,4 +1,4 @@
 .PHONY: run-local
 run-local:
-		DATABASE_URL=postgres://postgres:foobarbaz@localhost:5432/postgres \
-		go run main.go
+	DATABASE_URL=postgres://postgres:foobarbaz@localhost:5432/postgres \
+		go run main.go