Use Go Modules instead of Glock (fixes #338)

Previously, this project was using glock to manage external go
dependencies. As of go 1.11, go comes with builtin module support. Go
Modules fully supersede glock functionality. As of go 1.16, either an
environment variable or go modules are required for this project to
build.

This commit migrates the repository away from glock, and instead uses go
modules. This gets rid of an unneeded dependency, and also allows the
project to natively compile under go 1.16 (which requires `go.mod` by
default).

For go >= 1.13, compilation will "just work". To build under go 1.11 and
go 1.12 one needs to set an environment variable 'GO111MODULE=on'. Since
go <= 1.14 can be considered end of life, this change will likely not be
impact any existing build scripts.

This commit also updates the Travis Tests with more modern go versions,
so that they can pass.

.travis.yml

@@ -1,8 +1,8 @@
 language: go
 go:
-- "1.9"
-- "1.10"
-- "1.11"
+- "1.14"
+- "1.15"
+- "1.16"
 install:
 - make get-deps
 script:

Makefile

@@ -30,7 +30,7 @@ dist: dist-clean
 
 
 release: dist
-	glock sync -n < GLOCKFILE
+	go mod tidy
 	tar -cvzf docker-gen-alpine-linux-amd64-$(TAG).tar.gz -C dist/alpine-linux/amd64 docker-gen
 	tar -cvzf docker-gen-alpine-linux-arm64-$(TAG).tar.gz -C dist/alpine-linux/arm64 docker-gen
 	tar -cvzf docker-gen-alpine-linux-armhf-$(TAG).tar.gz -C dist/alpine-linux/armhf docker-gen
@@ -43,8 +43,7 @@ release: dist
 	tar -cvzf docker-gen-darwin-i386-$(TAG).tar.gz -C dist/darwin/i386 docker-gen
 
 get-deps:
-	go get github.com/robfig/glock
-	glock sync -n < GLOCKFILE
+	go get ./...
 
 check-gofmt:
 	if [ -n "$(shell gofmt -l .)" ]; then \

README.md

@@ -434,8 +434,11 @@ $ docker-gen -notify "/bin/bash /tmp/etcd.sh" -interval 10 templates/etcd.tmpl /
 
 ### Development
 
-This project uses [glock](https://github.com/robfig/glock) for managing 3rd party dependencies.
-You'll need to install glock into your workspace before hacking on docker-gen.
+This project uses [Go Modules](https://golang.org/ref/mod) for managing 3rd party dependencies.
+This means that at least `go 1.11` is required. 
+
+For `go 1.11` and `go 1.12` it is additionally required to manually enable support by setting `GO111MODULE=on`. 
+For later versions, this is not required. 
 
 ```
 $ git clone <your fork>

go.mod

@@ -0,0 +1,27 @@
+module github.com/jwilder/docker-gen
+
+go 1.11
+
+require (
+	github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 // indirect
+	github.com/BurntSushi/toml v0.3.1
+	github.com/Microsoft/go-winio v0.4.16 // indirect
+	github.com/Nvveen/Gotty v0.0.0-20120604004816-cd527374f1e5 // indirect
+	github.com/containerd/continuity v0.0.0-20210315143101-93e15499afd5 // indirect
+	github.com/docker/docker v1.4.2-0.20171014114940-f2afa2623594 // indirect
+	github.com/docker/go-connections v0.4.0 // indirect
+	github.com/docker/go-units v0.3.2 // indirect
+	github.com/fsouza/go-dockerclient v0.0.0-20171009031830-d2a6d0596004
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/google/go-cmp v0.5.5 // indirect
+	github.com/gorilla/context v1.1.1 // indirect
+	github.com/gorilla/mux v0.0.0-20160718151158-d391bea3118c // indirect
+	github.com/gotestyourself/gotestyourself v2.2.0+incompatible // indirect
+	github.com/opencontainers/image-spec v1.0.1 // indirect
+	github.com/opencontainers/runc v0.1.1 // indirect
+	github.com/opencontainers/selinux v1.8.0 // indirect
+	github.com/sirupsen/logrus v1.8.1 // indirect
+	github.com/stretchr/testify v1.7.0 // indirect
+	golang.org/x/sys v0.0.0-20210331175145-43e1dd70ce54 // indirect
+	gotest.tools v2.2.0+incompatible // indirect
+)