can't build the module

[SinisterSpatula]

Hi, I'm getting an error message when I build using xcaddy in a Dockerfile, go errors that say stuff is redeclared. Been stuck for a long while trying to figure out how to solve it. Initally I was using the official caddy-builder-alpine image, but your module requires go 1.24.0 and they haven't updated from 1.23 in that image yet.

error message:

25.86 2025/02/28 08:56:07 [INFO] exec (timeout=0s): /usr/local/go/bin/go build -o /usr/bin/caddy -ldflags -w -s -trimpath -tags nobadger,nomysql,nopgx 
26.60 # runtime
26.60 /usr/local/go/src/runtime/map.go:877:6: mapiterinit redeclared in this block
26.60   /usr/local/go/src/runtime/linkname_swiss.go:91:6: other declaration of mapiterinit
26.60 /usr/local/go/src/runtime/map.go:937:6: mapiternext redeclared in this block
26.60   /usr/local/go/src/runtime/linkname_swiss.go:144:6: other declaration of mapiternext
26.60 /usr/local/go/src/runtime/map.go:1519:6: reflect_mapiterinit redeclared in this block
26.60   /usr/local/go/src/runtime/linkname_swiss.go:123:6: other declaration of reflect_mapiterinit
26.60 /usr/local/go/src/runtime/map.go:1536:6: reflect_mapiternext redeclared in this block
26.60   /usr/local/go/src/runtime/linkname_swiss.go:173:6: other declaration of reflect_mapiternext
26.60 /usr/local/go/src/runtime/map.go:1550:6: reflect_mapiterkey redeclared in this block
26.60   /usr/local/go/src/runtime/linkname_swiss.go:191:6: other declaration of reflect_mapiterkey
26.60 /usr/local/go/src/runtime/map.go:1564:6: reflect_mapiterelem redeclared in this block
26.60   /usr/local/go/src/runtime/linkname_swiss.go:209:6: other declaration of reflect_mapiterelem
26.60 /usr/local/go/src/runtime/map_fast32_swiss.go:18:6: mapaccess1_fast32 redeclared in this block
26.60   /usr/local/go/src/runtime/map_fast32.go:13:6: other declaration of mapaccess1_fast32
26.60 /usr/local/go/src/runtime/map_fast32_swiss.go:29:6: mapaccess2_fast32 redeclared in this block
26.60   /usr/local/go/src/runtime/map_fast32.go:62:6: other declaration of mapaccess2_fast32
26.60 /usr/local/go/src/runtime/map_fast32_swiss.go:41:6: mapassign_fast32 redeclared in this block
26.60   /usr/local/go/src/runtime/map_fast32.go:113:6: other declaration of mapassign_fast32
26.60 /usr/local/go/src/runtime/map_fast32_swiss.go:52:6: mapassign_fast32ptr redeclared in this block
26.60   /usr/local/go/src/runtime/map_fast32.go:212:6: other declaration of mapassign_fast32ptr
26.60 /usr/local/go/src/runtime/map_fast32_swiss.go:52:6: too many errors
26.64 2025/02/28 08:56:08 [INFO] Skipping cleanup as requested; leaving folder intact: /tmp/buildenv_2025-02-28-0855.4189852179
26.64 2025/02/28 08:56:08 [FATAL] exit status 1
------
failed to solve: process "/bin/sh -c xcaddy build     --with github.com/caddy-dns/porkbun     --with github.com/greenpau/caddy-security     --with github.com/mholt/caddy-l4     --with github.com/caddyserver/transform-encoder     --with github.com/hslatman/caddy-crowdsec-bouncer/http@main     --with github.com/hslatman/caddy-crowdsec-bouncer/layer4@main     --with github.com/aksdb/caddy-cgi/v2" did not complete successfully: exit code: 1
root@0ceaf8fc5009:/opt/stacks/caddy#

My Dockerfile:

# Set Caddy version
ARG CADDY_VERSION=2.9.1
ARG GO_VERSION=1.24.0

# Use Caddy builder image
FROM caddy:${CADDY_VERSION}-builder-alpine AS builder

# Bring in ARGs to the build stage
ARG GO_VERSION

# Install necessary build tools
RUN apk add --no-cache git gcc musl-dev wget

# Download and install Go
RUN wget https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz && \
    tar -C /usr/local -xzf go${GO_VERSION}.linux-amd64.tar.gz && \
    rm go${GO_VERSION}.linux-amd64.tar.gz

# Set Go environment variables
ENV PATH /usr/local/go/bin:$PATH

# Build Caddy with the desired plugins
RUN xcaddy build \
    --with github.com/caddy-dns/porkbun \
    --with github.com/greenpau/caddy-security \
    --with github.com/mholt/caddy-l4 \
    --with github.com/caddyserver/transform-encoder \
    --with github.com/hslatman/caddy-crowdsec-bouncer/http@main \
    --with github.com/hslatman/caddy-crowdsec-bouncer/layer4@main \
    --with github.com/aksdb/caddy-cgi/v2

# Use a lightweight Caddy image for the final stage
FROM caddy:${CADDY_VERSION}-alpine

# Copy the custom Caddy binary
COPY --from=builder /usr/bin/caddy /usr/bin/caddy

# Run Caddy with the specified configuration
CMD ["caddy", "run", "--config", "/etc/caddy/Caddyfile", "--adapter", "caddyfile"]

[SinisterSpatula]

Disregard, I was able to solve it this way:

# Stage 1: Build Caddy with Go 1.24.0
FROM golang:1.24.0-alpine AS builder

# Set Caddy version
ARG CADDY_VERSION=2.9.1

# Install necessary build tools
RUN apk add --no-cache git gcc musl-dev

# Install xcaddy
RUN go install github.com/caddyserver/xcaddy/cmd/xcaddy@latest

# Build Caddy with the specified plugins
RUN xcaddy build v${CADDY_VERSION} \
    --output /usr/local/bin/caddy \
    --with github.com/caddy-dns/porkbun \
    --with github.com/greenpau/caddy-security \
    --with github.com/mholt/caddy-l4 \
    --with github.com/caddyserver/transform-encoder \
    --with github.com/hslatman/caddy-crowdsec-bouncer/http@main \
    --with github.com/hslatman/caddy-crowdsec-bouncer/layer4@main \
    --with github.com/aksdb/caddy-cgi/v2

# Stage 2: Create a lightweight runtime image
FROM alpine:latest

# Install runtime dependencies
RUN apk add --no-cache ca-certificates

# Copy Caddy binary from the builder stage
COPY --from=builder /usr/local/bin/caddy /usr/bin/caddy

# Run Caddy
CMD ["caddy", "run", "--config", "/etc/caddy/Caddyfile", "--adapter", "caddyfile"]

[demiGod095]

Using the previous version compiled successfully for me with caddy:2.9.1-builder

RUN xcaddy build \
    --with=github.com/aksdb/caddy-cgi/v2@v2.2.5

Can someone tell me if this is OK to do in prod ?
basic cgi hello world seems to be working.

Thank you.

[polarathene]

This issue can be closed?

Latest release of Caddy is 2.10.2 (Aug 2025), with the prior release in that same month raising the Go requirement for building to v1.25.0. The official image was updated alongside that with the images for Caddy v2.10.2 published Oct 2025 👍

compose.yaml:

services
  caddy:
    image: localhost/caddy:latest # image will be built and tagged with this name
    pull_policy: build # force build instead of attempting to pull
    build:
      # NOTE:
      # - `$$` escapes `$` to opt-out of the Docker Compose ENV interpolation feature.
      # - `ARG CADDY_VERSION` is only used by the `FROM` instructions.
      # - The builder's `RUN` instruction inherits the images own `ENV CADDY_VERSION=v2.10.2`
      #   (which contains the required `v` prefix), which is used as the `ARG` was not added into scope.
      # - xcaddy will by default use the `CADDY_VERSION` ENV it has available already:
      #   https://github.com/caddyserver/xcaddy#command-usage
      dockerfile_inline: |
        ARG CADDY_VERSION=2.10.2
        FROM caddy:$${CADDY_VERSION}-builder AS builder
        RUN xcaddy build \
          --with github.com/aksdb/caddy-cgi/v2

        FROM caddy:$${CADDY_VERSION}
        COPY --link --from=builder /usr/bin/caddy /usr/bin/caddy