copying * files in Docker to directory gives error - docker

Question

I have the following Dockerfile
FROM openjdk:8-jdk-alpine
RUN mkdir -p /webpieces
COPY * /webpieces
WORKDIR "/webpieces"
ENTRYPOINT ["./bin/webpiecesexample"]
When I build like so, I get the following error
Deans-MacBook-Pro:webpiecesexample dean$ docker build -t gcr.io/braided-topic/webpieces2 .
Sending build context to Docker daemon 75.56MB
Step 1/5 : FROM openjdk:8-jdk-alpine
---> a3562aa0b991
Step 2/5 : RUN mkdir -p /webpieces
---> Running in bc615c0cd540
Removing intermediate container bc615c0cd540
---> 69a2f4530c44
Step 3/5 : COPY * /webpieces
When using COPY with more than one source file, the destination must be a directory and end with a /
When I trim the DockerFile and just build with the first two lines and then run with a basic shell to view the directories, I see the webpieces directory there
docker run -it --entrypoint sh gcr.io/braided-topic-266113/webpieces2
I can cd into webpieces and everything. Why is the copy command not working here?
docker version here:
Deans-MacBook-Pro:distributions dean$ docker version
Client: Docker Engine - Community
Version: 19.03.5
API version: 1.40
Go version: go1.12.12
Git commit: 633a0ea
Built: Wed Nov 13 07:22:34 2019
OS/Arch: darwin/amd64
Experimental: false
Server: Docker Engine - Community
Engine:
Version: 19.03.5
API version: 1.40 (minimum version 1.12)
Go version: go1.12.12
Git commit: 633a0ea
Built: Wed Nov 13 07:29:19 2019
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: v1.2.10
GitCommit: b34a5c8af56e510852c35414db4c1f4fa6172339
runc:
Version: 1.0.0-rc8+dev
GitCommit: 3e425f80a8c931f88e6d94a8c831b9d5aa481657
docker-init:
Version: 0.18.0
GitCommit: fec3683

Answer 1

When using COPY with more than one source file, the destination must be a directory and end with a /.
Change the COPY line to
COPY * /webpieces/
...it seems to copy the contents of each directory instead of the directories themselves. I would prefer not to name each directory I am moving as we prefer auto-add when we make changes.
Use . instead of * and it'll preserve all the nesting.
COPY . /webpieces/