我应该安装哪些库才能在基于 Alpine 的图像中的 ASP NET Core 应用程序中使用 System.Drawing.Common

Question

I have the following code in dotnet core 3.0 application:

...
// This url returns image (Content-Type: Blob)
var imageUrl = "https://barcode.tec-it.com/barcode.ashx?data=ABC-abc-1234&code=Code128&dpi=96";
HttpClient client = HttpClientFactory.Create();
using (var input = await client.GetStreamAsync(imageUrl))
{
    var bitmap = new Bitmap(input); // this is dangerous code
}
...

I want to run this code inside docker container, which based on alpine3.9 (mcr.microsoft.com/dotnet/core/aspnet:3.0.0-alpine3.9) I know that I should install additional libraries inside docker container for working with System.Drawing.Common:

FROM mcr.microsoft.com/dotnet/core/aspnet:3.0.0-alpine3.9
RUN echo "http://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories \
    && apk update \
    && apk add \
        libgdiplus

But anyway - it fails with the following stacktrace:

System.ArgumentException: Parameter is not valid.
   at System.Drawing.Image.InitializeFromStream(Stream stream)
   at System.Drawing.Bitmap..ctor(Stream stream)

I know that this code works fine inside debian-based container which I cook like this:

FROM mcr.microsoft.com/dotnet/core/aspnet:3.0
RUN apt-get update \
    && apt-get install -y --no-install-recommends \
    libgdiplus

I tried to install libgdiplus-dev , fontconfig and ttf-dejavu libraries inside alpine container but it doesn't works

So the main question - is it libraries related issue or bug inside dotnet? If first - what libraries should I install for this to work?

Answer 1

TL;DR

change https://barcode.tec-it.com/barcode.ashx?data=ABC-abc-1234&code=Code128&dpi=96 to https://www.scandit.com/wp-content/themes/scandit/barcode-generator.php?symbology=code128&value=213214214&size=200&ec=L

DESCRIPTION

It is bug inside dotnet - https://github.com/dotnet/corefx/issues/41527 Issue link generates GIF - it causes issue. Workaround - use link which will generates JPEG

Answer 2

For me the following modification of dockerfile worked (.net core 3.1). Pay attention that libgdiplus, libc-dev and libx11-dev are added to the runtime:

FROM mcr.microsoft.com/dotnet/core/sdk:3.1-alpine3.12 as builder
WORKDIR /app
COPY nuget.config nuget.config

RUN apk update
RUN apk add --update nodejs nodejs-npm

RUN cd XXX.XXXXXXX.YYYYYY && dotnet restore --configfile ../nuget.config && 
dotnet publish -c Release -o ../out/

FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-alpine3.12
WORKDIR /app

# Alpine 3.x Docker images no longer have tzdata package 
RUN apk update && \
apk add --no-cache tzdata

RUN apk add libgdiplus --repository https://dl-3.alpinelinux.org/alpine/edge/testing/
RUN apk add libc-dev libx11-dev

COPY --from=builder /app/out .
CMD ["dotnet", "XXX.XXXXXXX.YYYYYY"]