Layer consolidation

.devcontainer/Dockerfile

@@ -1,34 +1,27 @@
-#-----------------------------------------------------------------------------------------
+#-------------------------------------------------------------------------------------------------------------
 # Copyright (c) Microsoft Corporation. All rights reserved.
-# Licensed under the MIT License. See LICENSE in the project root for license information.
-#-----------------------------------------------------------------------------------------
+# Licensed under the MIT License. See https://go.microsoft.com/fwlink/?linkid=2090316 for license information.
+#-------------------------------------------------------------------------------------------------------------
 
 FROM golang:1
 
-# Configure apt
+# Avoid warnings by switching to noninteractive
 ENV DEBIAN_FRONTEND=noninteractive
+
+# Configure apt, install packages and tools
 RUN apt-get update \
-    && apt-get -y install --no-install-recommends apt-utils 2>&1
-
-# gocode-gomod
-RUN go get -x -d github.com/stamblerre/gocode 2>&1 \
+    && apt-get -y install --no-install-recommends apt-utils 2>&1 \
+    #
+    # Verify git, process tools, lsb-release (common in install instructions for CLIs) installed
+    && apt-get -y install git procps lsb-release \
+    #
+    # Install gocode-gomod
+    && go get -x -d github.com/stamblerre/gocode 2>&1 \
     && go build -o gocode-gomod github.com/stamblerre/gocode \
-    && mv gocode-gomod $GOPATH/bin/
-
-# Install git, process tools, lsb-release (common in install instructions for CLIs)
-RUN apt-get -y install git procps lsb-release
-
-# Clean up
-RUN apt-get autoremove -y \
-    && apt-get clean -y \
-    && rm -rf /var/lib/apt/lists/*
-ENV DEBIAN_FRONTEND=dialog
-
-# Set the default shell to bash rather than sh
-ENV SHELL /bin/bash
-
-# go tools
-RUN go get -u -v \
+    && mv gocode-gomod $GOPATH/bin/ \
+    #
+    # Install Go tools
+    && go get -u -v \
         github.com/mdempsky/gocode \
         github.com/uudashr/gopkgs/cmd/gopkgs \
         github.com/ramya-rao-a/go-outline \
@@ -51,4 +44,9 @@ RUN go get -u -v \
         honnef.co/go/tools/... \
         github.com/golangci/golangci-lint/cmd/golangci-lint \
         github.com/mgechev/revive \
-    github.com/derekparker/delve/cmd/dlv 2>&1
+        github.com/derekparker/delve/cmd/dlv 2>&1 \
+    #
+    # Clean up
+    && apt-get autoremove -y \
+    && apt-get clean -y \
+    && rm -rf /var/lib/apt/lists/*