From 37ef1411ceb252e007bf91079bf69e8cf047fdd0 Mon Sep 17 00:00:00 2001
From: Blake Pettersson <blake.pettersson@gmail.com>
Date: Fri, 22 Sep 2023 12:48:16 +0200
Subject: [PATCH] build: cache go mod

For local development, to remove the step where go modules are
downloaded on every `docker build`, first copy only `go.mod` and
`go.sum` to the Docker workspace.

This step only needs to be performed whenever one of those files
changes.

Signed-off-by: Blake Pettersson <blake.pettersson@gmail.com>
---
 Dockerfile | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 0f8e1c61..f9fca9bb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,15 +4,14 @@ ARG LD_FLAGS='-s -w -linkmode external -extldflags "-static"'
 ARG TARGETPLATFORM
 
 WORKDIR /app
-COPY . .
 
 RUN export GOOS=$(echo ${TARGETPLATFORM} | cut -d / -f1) && \
     export GOARCH=$(echo ${TARGETPLATFORM} | cut -d / -f2)
 
-RUN go env
+COPY go.* ./
+RUN go env && go mod download
 
-RUN go get -d -v \
-    && go install -v
+COPY . .
 
 RUN CGO_ENABLED=1 go build -ldflags="${LD_FLAGS}" -tags="sqlite_unlock_notify" -o /app/build/policyreporter -v