How do i use Docker to build Golang Azure functions

Question

I was using below docker file but couldnot make it work. As golang is a custom one, so how do we install azure function core tools and run the container app.

FROM golang:1.22-alpine AS builder


RUN mkdir /app

ADD . /app

WORKDIR /app

RUN GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -o custom_handler custom_handler.go


# Final image based on Azure Functions runtime
FROM mcr.microsoft.com/azure-functions/v3:preview

WORKDIR /home/site/wwwroot

# Copy the compiled binary from the builder stage
COPY --from=builder /app/custom_handler ./

# Set the entrypoint to execute the function app
ENTRYPOINT ["./custom_handler"]

# Expose the port for HTTP triggers
EXPOSE 8080

Answer 1

Thanks for posting your question in the Microsoft Q&A forum.

It seems like there might be a couple of issues in your Dockerfile. Here's an updated version:

WORKDIR /app

# Copy the Go module files
COPY go.* ./

RUN go mod download

COPY . .

RUN CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -o custom_handler .

# Final image based on Azure Functions runtime
FROM mcr.microsoft.com/azure-functions/go:3.0

WORKDIR /home/site/wwwroot

# Copy the compiled binary from the builder stage
COPY --from=builder /app/custom_handler ./

# Set the entrypoint to execute the function app
ENTRYPOINT ["./custom_handler"]

# Expose the port for HTTP triggers
EXPOSE 8080

Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful

Answer 2

raviteja aketi Thanks for posting your question in Microsoft Q&A. From the description above, you are looking to build Golang function with docker and the question is on installing Azure Function Core Tools.

We have an Example of an Azure Function App golang custom handler source code and full description about the project is listed here. To install Functions Core Tools, check out Dockerfile which is built from base golang:1.17.6-bullseye and you can update to the latest supported versions. Full detailed instructions are available here (Install the Azure Functions Core Tools). I didn't see alpine is listed as supported but you can give a try with the same instructions or switch to bullseye and validate.

Note: azure-functions-core-tools-4 for V4 and azure-functions-core-tools-3 for V3

I hope this helps and let me know if you have any questions or face any errors.

---

If you found the answer to your question helpful, please take a moment to mark it as Yes for others to benefit from your experience. Or simply add a comment tagging me and would be happy to answer your questions.