私的GolangのDockerfile

.air.toml

# Config file for [Air](https://github.com/cosmtrek/air) in TOML format

# Working directory
# . or absolute path, please note that the directories following must be under root.
root = "."
tmp_dir = "tmp"

[build]
# Just plain old shell command. You could use `make` as well.
cmd = "go build -o ./tmp/main ./src/main.go"
# Binary file yields from `cmd`.
bin = "tmp/main"
# Customize binary, can setup environment variables when run your app.
full_bin = "APP_ENV=dev APP_USER=air ./tmp/main"
# Watch these filename extensions.
include_ext = ["go", "tpl", "tmpl", "html"]
# Ignore these filename extensions or directories.
exclude_dir = ["assets", "tmp", "vendor", "frontend/node_modules"]
# Watch these directories if you specified.
include_dir = []
# Exclude files.
exclude_file = []
# Exclude specific regular expressions.
exclude_regex = ["_test.go"]
# Exclude unchanged files.
exclude_unchanged = true
# Follow symlink for directories
follow_symlink = true
# This log file places in your tmp_dir.
log = "air.log"
# It's not necessary to trigger build each time file changes if it's too frequent.
delay = 1000 # ms
# Stop running old binary when build errors occur.
stop_on_error = true
# Send Interrupt signal before killing process (windows does not support this feature)
send_interrupt = false
# Delay after sending Interrupt signal
kill_delay = 500 # ms

[log]
# Show log time
time = false

[color]
# Customize each part's color. If no color found, use the raw app log.
main = "magenta"
watcher = "cyan"
build = "yellow"
runner = "green"

[misc]
# Delete tmp directory on exit
clean_on_exit = true

docker-compose.yaml

version: "3.8"

services:
  server:
    build:
      context: .
      dockerfile: Dockerfile
      target: Dev
    stdin_open: true
    tty: true
    ports:
      - 80:80
    volumes:
      - type: bind
        source: src
        target: /go/app/src

Dockerfile

# ============
# Dev
# ============
FROM golang:1.18.3 as Dev
ENV TZ=Asia/Tokyo

ENV CGO_ENABLED=0
ENV GOOS=linux
ENV GOARCH=amd64
ENV ROOTPATH=/go/app

WORKDIR ${ROOTPATH}

RUN go install github.com/cosmtrek/air@v1.40.0
COPY go.mod go.sum .air.toml ./
RUN go mod download

COPY src/ ${ROOTPATH}/src/

CMD ["air", "-c", ".air.toml"]


# ============
# Builder
# ============
FROM golang:1.18.3 as Builder
ENV TZ=Asia/Tokyo

ENV CGO_ENABLED=0
ENV GOOS=linux
ENV GOARCH=amd64
ENV ROOTPATH=/go/app

WORKDIR ${ROOTPATH}

COPY go.mod go.sum ./
RUN go mod download

COPY src/ ${ROOTPATH}/src/

RUN go build \
    -o ${ROOTPATH}/bin/main \
    -ldflags '-s -w' \
    ./src/main.go


# ============
# Deploy
# ============
FROM gcr.io/distroless/static-debian11
ENV TZ=Asia/Tokyo

COPY --from=Builder /go/app/bin/main /app/main

EXPOSE 8080
USER nonroot:nonroot
CMD ["/app/main"]