What package should I install instead of libpcre++-dev to use C code in Alpine Golang? - docker

Question

I have a Golang program inside a docker container (I use Ubuntu 18). Also I use github.com/glenn-brown/golang-pkg-pcre/src/pkg/pcre for regex in my Golang app. Before using this library I should install libpcre++-dev this way:
sudo apt-get install libpcre++-dev
But I use golang:alpine in my Dockerfile and this is no libpcre++-dev library in alpine packages.
What package should I install instead of libpcre++-dev?
p.s. I have tried to install libc6-compat, pcre pcre-dev, libpcrecpp but I see this error:
github.com/glenn-brown/golang-pkg-pcre/src/pkg/pcre
/go/pkg/mod/github.com/glenn-brown/golang-pkg-pcre#v0.0.0-20120522223659-48bb82a8b8ce/src/pkg/pcre/pcre.go:52:10:
fatal error: pcre.h: No such file or directory #include
^~~~~~~~ compilation terminated
My Dockerfile:
FROM golang:alpine
RUN apk update
RUN apk upgrade
RUN apk add --update --no-cache build-base gcc g++ pcre pcre-dev libc6-compat
# Install git + SSL ca certificates.
# Git is required for fetching the dependencies.
# Ca-certificates is required to call HTTPS endpoints.
RUN apk update && apk add --no-cache curl git ca-certificates tzdata \
&& update-ca-certificates 2> /dev/null || true
I build my app this way:
- CGO_ENABLED=1 GOOS=linux GOARCH=amd64 go build -a -installsuffix cgo -ldflags="-w -s" -o bin/backend ./cmd/backend/main.go
EDIT
I have change my Dockerfile (add line below)
RUN apk add --update --no-cache build-base gcc g++ pcre pcre-dev libc6-compat
And now I have a new error:
Error loading shared library libpcre.so.1: No such file or directory
(needed by /bin/backend)

Answer 1

You can try one of these, as both package
RUN apk add --virtual build-dependencies
RUn apk add --no-cache build-base gcc
build-essential is a metapackage (a package that installs many other
packages, like g++ and gcc: the GNU C & C++ compilers).
Or you can install the alpine sdk.
You can start with alpine-sdk, which is a "metapackage that pulls in
the most essential packages used to build new packages."
http://wiki.alpinelinux.org/wiki/Developer_Documentation has more
info.
RUN apk add --update alpine-sdk
docker-alpine-issues-24
Or you can use golang:latest which will work fine.
FROM golang:latest
RUN apt-get update
RUN apt-get install libpcre++-dev -y

Answer 2

You can use one of the Debian-based golang images instead. By the time you're installing GNU libc and a full C toolchain on top of this anyways, there's not really going to be much space savings over the Alpine base image. You can (and should) use a multi-stage build where the final image just contains your compiled binary, and that can use an Alpine base.
The result would look something like:
# Build-time image; just has the parts needed to run `go build`
FROM golang:1.12-buster AS build
# Install additional build-time tools
RUN apt-get update \
&& apt-get install --assume-yes \
build-essential ca-certificates git-core tzdata \
libpcre++-dev
# Build your application
WORKDIR /app
COPY . .
ENV GO111MODULE=on
RUN go build -o myapp ./cmd/myapp
# Runtime image; has only what we need to run the application
FROM alpine:3.10
# Note that you'll need the shared library for libpcre++
RUN apk add ca-certificates tzdata libpcrepp
COPY --from=build /app/myapp /usr/bin/myapp
CMD ["myapp"]