Add docker runtime image (#21)

Closes #17

.travis.yml

@@ -2,13 +2,9 @@ sudo: required
 services:
   - docker
 install:
-  - curl -fsSL https://github.com/docker/compose/releases/download/1.12.0/docker-compose-`uname -s`-`uname -m` > docker-compose
-  - chmod +x docker-compose
-  - sudo mv docker-compose /usr/local/bin/docker-compose
+  - docker version
   - docker-compose version
-  - docker-compose pull
-  - docker-compose build
-  - docker-compose up -d
-  - docker-compose run dbmate go version
 script:
   - make
+  - docker build -t dbmate .
+  - docker run --rm dbmate --help

Dockerfile

@@ -1,4 +1,5 @@
-FROM golang:1.9
+# build image
+FROM golang:1.9 as build
 
 # required to force cgo (for sqlite driver) with cross compile
 ENV CGO_ENABLED 1
@@ -13,6 +14,9 @@ COPY . $GOPATH/src/github.com/amacneil/dbmate
 WORKDIR $GOPATH/src/github.com/amacneil/dbmate
 
 # build
-RUN go install -v ./cmd/dbmate
+RUN go build -ldflags '-s' -o /go/bin/dbmate ./cmd/dbmate
 
-CMD dbmate
+# runtime image
+FROM debian:stretch-slim
+COPY --from=build /go/bin/dbmate /usr/local/bin/dbmate
+ENTRYPOINT ["dbmate"]

Makefile

@@ -13,14 +13,14 @@ container:
 	$(DC) up -d
 
 lint:
-	$(DC) run dbmate golint -set_exit_status $(PACKAGES)
-	$(DC) run dbmate go vet $(PACKAGES)
-	$(DC) run dbmate errcheck $(PACKAGES)
+	$(DC) run --rm dbmate golint -set_exit_status $(PACKAGES)
+	$(DC) run --rm dbmate go vet $(PACKAGES)
+	$(DC) run --rm dbmate errcheck $(PACKAGES)
 
 test:
-	$(DC) run dbmate go test -v $(PACKAGES)
+	$(DC) run --rm dbmate go test -v $(PACKAGES)
 
 build: clean
-	$(DC) run -e GOARCH=amd64 dbmate go build $(BUILD_FLAGS) -o dist/dbmate-linux-amd64 ./cmd/dbmate
+	$(DC) run --rm -e GOARCH=amd64 dbmate go build $(BUILD_FLAGS) -o dist/dbmate-linux-amd64 ./cmd/dbmate
 	# musl target does not support sqlite
-	$(DC) run -e GOARCH=amd64 -e CGO_ENABLED=0 dbmate go build $(BUILD_FLAGS) -o dist/dbmate-linux-musl-amd64 ./cmd/dbmate
+	$(DC) run --rm -e GOARCH=amd64 -e CGO_ENABLED=0 dbmate go build $(BUILD_FLAGS) -o dist/dbmate-linux-musl-amd64 ./cmd/dbmate

README.md

@@ -42,6 +42,14 @@ $ sudo curl -fsSL -o /usr/local/bin/dbmate https://github.com/amacneil/dbmate/re
 $ sudo chmod +x /usr/local/bin/dbmate
 ```
 
+**Docker**
+
+You can run dbmate using the official docker image:
+
+```sh
+$ docker run --rm amacneil/dbmate --help
+```
+
 **Heroku**
 
 To use dbmate on Heroku, the easiest method is to store the linux binary in your git repository:
@@ -55,7 +63,7 @@ $ git commit -m "Add dbmate binary"
 $ git push heroku master
 ```
 
-You can now run dbmate on heroku:
+You can then run dbmate on heroku:
 
 ```sh
 $ heroku run bin/dbmate-heroku up

docker-compose.yml

@@ -1,7 +1,9 @@
-version: '2.1'
+version: '2.3'
 services:
   dbmate:
-    build: .
+    build:
+      context: .
+      target: build
     volumes:
       - .:/go/src/github.com/amacneil/dbmate
     depends_on: