bake cache misses with multiple targets #414
Description
I was hoping to speed up builds by using the parallelism provided by bake.
Therfore i'm running buildx bake -f docker-bake.hcl
group "default" {
targets = [ "s1","s2","s3","s4","s5","s6","s7","s8","s9","s10","s11","s12","s13","s14","s15","s16","s17","s18","s19","s20","s21"]
}
target "s1" {
context = "./s1"
}
target "s2" {
context = "./s2"
}
target "s3" {
context = "./s3"
}
...
target "s21" {
context = "./s21"
}but nearly all of the time one (or more) of the images gets rebuilt, even if they should hit the cache.
=> CACHED [s1 build-app.web 2/7] WORKDIR /app 0.0s
=> CACHED [s1 build-app.web 3/7] COPY package*.json /app/ 0.0s
=> CACHED [s1 build-app.web 4/7] RUN npm ci 0.0s
=> CACHED [s1 build-app.web 5/7] COPY ./*.json /app/ 0.0s
=> CACHED [s1 build-app.web 6/7] COPY ./src /app/src 0.0s
=> [s19 build 6/6] RUN npm run build 2.8s
If i specify single targets, the cache is used as i would expect:
for i in {1..21}; do buildx bake -f docker-bake.hcl s$i; done
What if found out so far:
- The more default targets i have, the less likely the cache is used for some of them.
- When i try to reproduce this with trivial Dockerfiles containing only a single
RUNthe problem doesn't occure
Are there any ideas why this is happening or how i could investigate this further?