CI: Fail build if code is wrongly formatted

.travis.yml

@@ -15,6 +15,9 @@ env:
 matrix:
   fast_finish: true
 
+before_install:
+  - make -f _dev/Makefile fmtcheck
+
 install:
   - sudo pip install docker
 

README.md

@@ -61,7 +61,8 @@ There are number of things that need to be setup before running tests. Most impo
 
 ```
 git clone https://github.com/cloudflare/tls-tris.git
-cd tls-tris; make -f _dev/Makefile build-all
+cd tls-tris; cp _dev/utils/pre-commit .git/hooks/ 
+make -f _dev/Makefile build-all
 ```
 
 ### Testing

_dev/Makefile

@@ -112,5 +112,7 @@ clean:
 clean-all: clean
 	rm -rf $(BUILD_DIR)
 
+fmtcheck:
+	$(DEV_DIR)/utils/fmtcheck.sh
 
 .PHONY: $(BUILD_DIR) clean build build-test test test-unit test-bogo test-compat

_dev/utils/fmtcheck.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+# Copyright 2012 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+gofiles=$(find . -iname "*.go" ! -path "*/_dev/*")
+#[ -z "$gofiles" ] && exit 0
+
+unformatted=$(gofmt -l $gofiles)
+[ -z "$unformatted" ] && exit 0
+
+# Some files are not gofmt'd. Print message and fail.
+
+echo >&2 "Go files must be formatted with gofmt. Please run:"
+for fn in $unformatted; do
+	echo >&2 "  gofmt -w $PWD/$fn"
+done
+
+exit 1
+

_dev/utils/pre-commit

@@ -0,0 +1,27 @@
+#!/bin/sh
+# Copyright 2012 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+# git gofmt pre-commit hook
+#
+# To use, store as .git/hooks/pre-commit inside your repository and make sure
+# it has execute permissions.
+#
+# This script does not handle file names that contain spaces.
+
+gofiles=$(git diff --cached --name-only --diff-filter=ACM | grep '\.go$')
+[ -z "$gofiles" ] && exit 0
+
+unformatted=$(gofmt -l $gofiles)
+[ -z "$unformatted" ] && exit 0
+
+# Some files are not gofmt'd. Print message and fail.
+
+echo >&2 "Go files must be formatted with gofmt. Please run:"
+for fn in $unformatted; do
+	echo >&2 "  gofmt -w $PWD/$fn"
+done
+
+exit 1
+