Go Dockerfile 问题 为什么找不到二进制 dlv 没有这样的文件或目录

您在基于alpine的发行版中构建了dlv个.dlv个可执行文件与libc.musl个链接:

# ldd dlv 
        linux-vdso.so.1 (0x00007ffcd251d000)
        libc.musl-x86_64.so.1 => not found

但后来你切换到了基于glibc的图像debian:buster-slim.该映像没有所需的库.

# find / -name libc.musl*                                        
<nothing found>

这就是为什么不能执行dlv--动态链接器找不到正确的库.

您需要内置基于glibc的对接器.例如，替换第一行

FROM golang:bullseye AS builder

顺便说一句.构建之后，您需要在特权模式下运行容器

$ docker build . -t try-dlv
...
$ docker run --privileged --rm try-dlv
API server listening at: [::]:40000
2022-10-30T10:51:02Z warning layer=rpc Listening for remote connections (connections are not authenticated nor encrypted)

在非特权容器dlv中，不允许产生子进程.

$ docker run --rm try-dlv
API server listening at: [::]:40000
2022-10-30T10:55:46Z warning layer=rpc Listening for remote connections (connections are not authenticated nor encrypted)
could not launch process: fork/exec /app/fooapp: operation not permitted

Really Minimal Image个

你用debian:buster-slim来最小化图像，它的大小是80MB.但如果您需要really small映像，则使用busybox，其开销仅为4.86MB.

FROM golang:bullseye AS builder

# Build Delve for debugging
RUN go install github.com/go-delve/delve/cmd/dlv@latest

# Create and change to the app directory.
WORKDIR /app
ENV CGO_ENABLED=0

# Retrieve application dependencies.
COPY go.* ./
RUN go mod download

# Copy local code to the container image.
COPY . ./

# Build the binary.
RUN go build -o fooapp .

# Download certificates
RUN set -x && apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
    ca-certificates 

# Use the official Debian slim image for a lean production container.
FROM busybox:glibc

EXPOSE 8000 40000

# Copy the binary to the production image from the builder stage.
COPY --from=builder /app/fooapp /app/fooapp 
# COPY --from=builder /app/ /app

COPY --from=builder /go/bin/dlv /dlv

COPY --from=builder /etc/ssl /etc/ssl

# Run dlv as pass fooapp as parameter
CMD ["/dlv", "--listen=:40000", "--headless=true", "--api-version=2", "--accept-multiclient", "exec", "/app/fooapp"]
# ENTRYPOINT ["/bin/sh"]

图像大小为25MB，其中18MB来自dlv，2MB来自Hello Worldapply.

在 Select 图像时，应注意具有相同的libc种口味.golang:bullseye个链接对glibc个链接.因此，最小图像必须是基于glibc的.

但如果你想要更舒适一点，使用安装了gcompat包的alpine.它是一个相当丰富的Linux，有很多外部包，只需要额外的6MB，而不是busybox MB.

FROM golang:bullseye AS builder

# Build Delve for debugging
RUN go install github.com/go-delve/delve/cmd/dlv@latest

# Create and change to the app directory.
WORKDIR /app
ENV CGO_ENABLED=0

# Copy local code to the container image.
COPY . ./

# Retrieve application dependencies.
RUN go mod tidy

# Build the binary.
RUN go build -o fooapp .

# Use alpine lean production container.
# FROM busybox:glibc
FROM alpine:latest

# gcompat is the package to glibc-based apps
# ca-certificates contains trusted TLS CA certs
# bash is just for the comfort, I hate /bin/sh
RUN apk add gcompat ca-certificates bash

EXPOSE 8000 40000

# Copy the binary to the production image from the builder stage.
COPY --from=builder /app/fooapp /app/fooapp 
# COPY --from=builder /app/ /app

COPY --from=builder /go/bin/dlv /dlv

# Run dlv as pass fooapp as parameter
CMD ["/dlv", "--listen=:40000", "--headless=true", "--api-version=2", "--accept-multiclient", "exec", "/app/fooapp"]
# ENTRYPOINT ["/bin/bash"]