Update to Delve 1.4.0 but change --only-same-user default to false (#38)

Author: briandealwis

go/Dockerfile

@@ -1,8 +1,18 @@
 FROM golang:1.14.1 as delve
-RUN curl --location --output delve-1.3.1.tar.gz https://github.com/go-delve/delve/archive/v1.3.1.tar.gz \
-  && tar xzf delve-1.3.1.tar.gz
+
+RUN curl --location --output delve-1.4.0.tar.gz https://github.com/go-delve/delve/archive/v1.4.0.tar.gz \
+  && tar xzf delve-1.4.0.tar.gz
+
+# Patch delve to change default for --only-same-user to false
+# Required as `kubectl port-forward` to dlv port is refused.
+# We must install patch(1) to apply the patch.
+COPY delve-only-same-user.patch .
+RUN apt-get update && apt-get install -y --no-install-recommends \
+  patch \
+  && patch -p0 < delve-only-same-user.patch
+
 # Produce an as-static-as-possible dlv binary to work on musl and glibc
-RUN cd delve-1.3.1 && CGO_ENABLED=0 go build -o /go/dlv -ldflags '-extldflags "-static"' ./cmd/dlv/
+RUN cd delve-1.4.0 && CGO_ENABLED=0 go build -o /go/dlv -ldflags '-extldflags "-static"' ./cmd/dlv/
 
 # Now populate the duct-tape image with the language runtime debugging support files
 # The debian image is about 95MB bigger

go/delve-only-same-user.patch

@@ -0,0 +1,13 @@
+diff --git delve-1.4.0/cmd/dlv/cmds/commands.go delve-1.4.0/cmd/dlv/cmds/commands.go
+index 0a17860..7e46206 100644
+--- delve-1.4.0/cmd/dlv/cmds/commands.go
++++ delve-1.4.0/cmd/dlv/cmds/commands.go
+@@ -114,7 +114,7 @@ func New(docCall bool) *cobra.Command {
+ 	RootCommand.PersistentFlags().StringVar(&BuildFlags, "build-flags", buildFlagsDefault, "Build flags, to be passed to the compiler.")
+ 	RootCommand.PersistentFlags().StringVar(&WorkingDir, "wd", ".", "Working directory for running the program.")
+ 	RootCommand.PersistentFlags().BoolVarP(&CheckGoVersion, "check-go-version", "", true, "Checks that the version of Go in use is compatible with Delve.")
+-	RootCommand.PersistentFlags().BoolVarP(&CheckLocalConnUser, "only-same-user", "", true, "Only connections from the same user that started this instance of Delve are allowed to connect.")
++	RootCommand.PersistentFlags().BoolVarP(&CheckLocalConnUser, "only-same-user", "", false, "Only connections from the same user that started this instance of Delve are allowed to connect.")
+ 	RootCommand.PersistentFlags().StringVar(&Backend, "backend", "default", `Backend selection (see 'dlv help backend').`)
+ 
+ 	// 'attach' subcommand.