diff --git a/Dockerfile b/Dockerfile
index 6a0dbf3..d8d3825 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,18 +1,21 @@
 FROM golang:alpine as builder
 
-ADD . /go/src/github.com/Luzifer/ots
+COPY . /go/src/github.com/Luzifer/ots
 WORKDIR /go/src/github.com/Luzifer/ots
 
 RUN set -ex \
  && apk add --update git \
- && go install -ldflags "-X main.version=$(git describe --tags || git rev-parse --short HEAD || echo dev)"
+ && go install \
+      -ldflags "-X main.version=$(git describe --tags --always || echo dev)" \
+      -mod=readonly
 
 FROM alpine:latest
 
 LABEL maintainer "Knut Ahlers <knut@ahlers.me>"
 
 RUN set -ex \
- && apk --no-cache add ca-certificates
+ && apk --no-cache add \
+      ca-certificates
 
 COPY --from=builder /go/bin/ots /usr/local/bin/ots
 
diff --git a/Dockerfile.minimal b/Dockerfile.minimal
index 63a3d9a..0f9b4cd 100644
--- a/Dockerfile.minimal
+++ b/Dockerfile.minimal
@@ -2,12 +2,14 @@ FROM golang:alpine as builder
 
 ENV CGO_ENABLED=0
 
-ADD . /go/src/github.com/Luzifer/ots
+COPY . /go/src/github.com/Luzifer/ots
 WORKDIR /go/src/github.com/Luzifer/ots
 
 RUN set -ex \
  && apk add --update git \
- && go install -ldflags "-X main.version=$(git describe --tags || git rev-parse --short HEAD || echo dev)"
+ && go install \
+      -ldflags "-X main.version=$(git describe --tags --always || echo dev)" \
+      -mod=readonly
 
 FROM scratch