Docker build dumps tarballs in ./tmp instead of cluttering project root

.gitignore

@@ -3,3 +3,4 @@
 /client/bwtest
 /client/libbottledwater.a
 /kafka/bottledwater
+tmp

Makefile

@@ -15,12 +15,15 @@ clean:
 	$(MAKE) -C client clean
 	$(MAKE) -C kafka clean
 
-docker: avro-1.7.7.tar.gz librdkafka-0.9.0.tar.gz bottledwater-bin.tar.gz bottledwater-ext.tar.gz
+docker: tmp/avro-1.7.7.tar.gz tmp/librdkafka-0.9.0.tar.gz tmp/bottledwater-bin.tar.gz tmp/bottledwater-ext.tar.gz
 	docker build -f build/Dockerfile.postgres -t local-postgres-bw:$(DOCKER_TAG) .
 	docker build -f build/Dockerfile.client -t local-bottledwater:$(DOCKER_TAG) .
 
-%.tar.gz: docker-build
-	docker run --rm bwbuild:$(DOCKER_TAG) cat /$@ > $@
+tmp:
+	mkdir tmp
+
+tmp/%.tar.gz: tmp docker-build
+	docker run --rm bwbuild:$(DOCKER_TAG) cat /$*.tar.gz > $@
 
 docker-build:
 	docker build -f build/Dockerfile.build -t bwbuild:$(DOCKER_TAG) .

build/Dockerfile.build

@@ -8,10 +8,10 @@
 #   docker build -f build/Dockerfile.build -t bwbuild:v1 .
 #   docker run -it --name bwbuild --rm bwbuild:v1 bash
 #   (Meanwhile, in another terminal:)
-#   docker cp bwbuild:/avro-1.7.7.tar.gz .
-#   docker cp bwbuild:/librdkafka-0.9.0.tar.gz .
-#   docker cp bwbuild:/bottledwater-ext.tar.gz .
-#   docker cp bwbuild:/bottledwater-bin.tar.gz .
+#   docker cp bwbuild:/avro-1.7.7.tar.gz tmp/
+#   docker cp bwbuild:/librdkafka-0.9.0.tar.gz tmp/
+#   docker cp bwbuild:/bottledwater-ext.tar.gz tmp/
+#   docker cp bwbuild:/bottledwater-bin.tar.gz tmp/
 #   (Now type `exit` in the bash shell above.)
 #
 # See the other Dockerfiles in this directory for using those build artifacts.

build/Dockerfile.client

@@ -12,9 +12,9 @@ RUN apt-get update && \
     apt-get upgrade -y && \
     apt-get install -y libcurl3 libjansson4 libpq5
 
-ADD avro-1.7.7.tar.gz /
-ADD librdkafka-0.9.0.tar.gz /
-ADD bottledwater-bin.tar.gz /
+ADD tmp/avro-1.7.7.tar.gz /
+ADD tmp/librdkafka-0.9.0.tar.gz /
+ADD tmp/bottledwater-bin.tar.gz /
 
 RUN cp /usr/local/lib/librdkafka.so.1 /usr/lib/x86_64-linux-gnu && \
     cp /usr/local/lib/libavro.so.22.0.0 /usr/lib/x86_64-linux-gnu

build/Dockerfile.postgres

@@ -18,7 +18,7 @@
 
 FROM postgres:9.4
 
-ADD bottledwater-ext.tar.gz /
-ADD avro-1.7.7.tar.gz /
+ADD tmp/bottledwater-ext.tar.gz /
+ADD tmp/avro-1.7.7.tar.gz /
 RUN cp /usr/local/lib/libavro.so.22.0.0 /usr/lib/x86_64-linux-gnu/libavro.so.22.0.0
 COPY build/replication-config.sh /docker-entrypoint-initdb.d/replication-config.sh