Docker - Permission Denied when Write Files to Host

1. Dockerfile

I created a normal user JohnnyChu to run the program in docker.
It will write a log file in /data/log inner container and container volume bind the host /foo/log. Now, it will occur permission denied problem.

# build stage
FROM golang:1.12.9-alpine AS build-env
RUN apk update -qq && apk --no-cache add git gcc g++
COPY . /src/
ARG BUILD_ENV
RUN cd /src && go build -tags ${BUILD_ENV} -o /src/dist/app

# final stage
FROM alpine:3.10.2
WORKDIR /app/
COPY --from=build-env /src/dist/ /app/
RUN addgroup -S JohnnyChu && adduser -S JohnnyChu -G JohnnyChu && chown -R JohnnyChu:JohnnyChu /app/
USER JohnnyChu
EXPOSE 8080
ENTRYPOINT ["./app"]

2. Run

# docker run -v /foo/log:/data/log  ... --name boo ...

2. Check User UID:GID inner Container.

# docker exec -it boo sh
/app $ cat /etc/passwd
...
...
guest:x:405:100:guest:/dev/null:/sbin/nologin
nobody:x:65534:65534:nobody:/:/sbin/nologin
JohnnyChu:x:100:101:Linux User,,,:/home/JohnnyChu:/sbin/nologin <--- UID:100 GID:101

3. Chown Host's Log Folder

# chown -R 100:101 /foo/log

4. Restart Container

# docker restart boo