Dependencies (vendor) are pre-loaded in build image

build/docker/bin/Dockerfile

@@ -34,6 +34,15 @@ RUN strip /opt/rocksdb/ldb /opt/rocksdb/sst_dump && \
 
 RUN go get github.com/golang/dep/cmd/dep
 
+RUN \
+    cleanup() { rm -rf $GOPATH/src/blockbook; } && \
+    trap cleanup EXIT && \
+    cd $GOPATH/src && \
+    git clone https://github.com/trezor/blockbook.git && \
+    cd blockbook && \
+    dep ensure -vendor-only && \
+    cp -r vendor /build/vendor
+
 ADD Makefile /build/Makefile
 
 VOLUME /out

build/docker/bin/Makefile

@@ -42,7 +42,7 @@ prepare-sources:
 prepare-vendor:
 	@ if [ "$(UPDATE_VENDOR)" -eq 1 ]; then \
 		echo "Updating vendor"; \
-		cd $(BLOCKBOOK_SRC) && rm -rf vendor?* && dep ensure -vendor-only ; \
+		cd $(BLOCKBOOK_SRC) && rm -rf vendor* && cp -r /build/vendor . && dep ensure -vendor-only ; \
 	else \
 		echo "Update of vendor not demanded, keeping version from src" ; \
 	fi