Docker container exit with error code error libcurl not found - docker

Question

I am building a container, you can see the docker file, its for rust app deployment on Argonaut. but its not able to start. Here you can see the Dockerfile.
FROM rust:1.64.0-buster AS builder
WORKDIR /app
ARG TOKEN
ARG DATABASE_URL
RUN git config --global url."https://${TOKEN}:#github.com/".insteadOf "https://github.com/"
COPY . .
ENV CARGO_NET_GIT_FETCH_WITH_CLI true
RUN rustup component add rustfmt
RUN apt-get update -y && apt-get install git wget ca-certificates curl gnupg lsb-release cmake libcurl4 -y
RUN cargo build
FROM debian:buster-slim
WORKDIR /app
COPY --from=builder /app/target/debug/linkedin /app/target/release/linkedin
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
CMD ["/app/target/release/linkedin"]
EXPOSE 3000
It builds successfully but when it works it gets exit with error code 127.
linkedin-leadr-1 | /app/target/release/linkedin: error while loading shared libraries: libcurl.so.4: cannot open shared object file: No such file or directory
Have not found what's wrong with it, even though I am installing libcurl4. but my docker container is not able to find it. Can you please give me the solution?

Answer 1

As you install libcurl4 in your build environment but not in your execution environment, that's most likely the reason.
There are two ways to solve this:
Install libcurl4 in your final image, or
Link statically by replacing cargo build with
RUN rustup target add x86_64-unknown-linux-musl
RUN cargo build --target=x86_64-unknown-linux-musl --release
The --release flag should get added either way, as I'm sure you don't want to deliver unoptimized debug builds to your enduser ;)
Note that if you choose to install libcurl4 in your final image, you need to clean up the apt cache afterwards, otherwise your image grows immensely:
RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install --yes \
libcurl4 \
&& apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
The full Dockerfile with libcurl4 installed would then look like this:
FROM rust:1.64.0-buster AS builder
WORKDIR /app
ARG TOKEN
ARG DATABASE_URL
RUN git config --global url."https://${TOKEN}:#github.com/".insteadOf "https://github.com/"
COPY . .
ENV CARGO_NET_GIT_FETCH_WITH_CLI true
RUN rustup component add rustfmt
RUN apt-get update -y && apt-get install git wget ca-certificates curl gnupg lsb-release cmake libcurl4 -y
RUN cargo build
# Copy the libcurl shared library from the builder stage into the final container
RUN mkdir -p /usr/local/lib && \
cp /usr/lib/x86_64-linux-gnu/libcurl.so.4 /usr/local/lib && \
ln -s /usr/local/lib/libcurl.so.4 /usr/local/lib/libcurl.so
FROM debian:buster-slim
RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install --yes \
libcurl4 \
&& apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
WORKDIR /app
COPY --from=builder /app/target/debug/linkedin /app/target/release/linkedin
COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
CMD ["/app/target/release/linkedin"]
EXPOSE 3000