Docker构建命令行过长，重复使用--build-arg是否有更优方案？

Absolutely, dealing with a sprawling docker build command stuffed with endless --build-arg flags is such a headache—no one wants to type (or maintain) that mess. Here are some cleaner, more scalable alternatives:

1. Use a Build Argument File (--build-arg-file) #

If you're running Docker 23.0 or newer, this is the simplest fix. Docker added support for loading build arguments from a file directly, so you can dump all your args into a single file instead of listing them one by one.

First, create a file (let's call it build-args.env) with your arguments in key-value pairs:

APP_VERSION=1.2.3
DB_HOST=db.example.com
API_KEY="abc123-with-spaces"  # Quote values that have spaces
# This is a comment, it'll be ignored

Then run your build command like this:

docker build --build-arg-file build-args.env -t myapp:latest .

Pro tip: The file uses the same syntax as .env files—no spaces around the = sign, and comments start with #.

2. Auto-Pass Environment Variables #

If your build arguments match environment variables on your host machine, you can skip explicit --build-arg flags entirely by linking them in your Dockerfile.

In your Dockerfile, set each ARG to default to the corresponding host environment variable:

ARG APP_VERSION=${APP_VERSION}
ARG DB_HOST=${DB_HOST}

RUN echo "Building app version: $APP_VERSION"
RUN echo "Connecting to DB at: $DB_HOST"

Then, either export the variables in your shell:

export APP_VERSION=1.2.3
export DB_HOST=db.example.com
docker build -t myapp:latest .

Or load them from a .env file using the --env-file flag:

docker build --env-file .env -t myapp:latest .

Docker will automatically pull in any environment variables that match your ARG names.

3. Use Docker Compose for Builds #

If you're already using Docker Compose for your project, it's perfect for centralizing build arguments. Just define your args in the build section of your docker-compose.yml:

services:
  myapp:
    build:
      context: .
      dockerfile: Dockerfile
      args:
        APP_VERSION: 1.2.3
        DB_HOST: db.example.com
        API_KEY: abc123
    image: myapp:latest

You can even pull values from a .env file to keep sensitive data separate:

# docker-compose.yml
services:
  myapp:
    build:
      context: .
      args:
        APP_VERSION: ${APP_VERSION}
        DB_HOST: ${DB_HOST}

Then just run:

docker-compose build

This keeps all your build configuration in one place, making it easy to update and share with your team.

4. Wrap the Command in a Shell Script #

If you need compatibility with older Docker versions or want more control, a simple shell script can eliminate the need to type all those flags every time.

Create a build.sh file:

#!/bin/bash

# Define your build arguments here
APP_VERSION="1.2.3"
DB_HOST="db.example.com"
API_KEY="abc123"

# Run the build command
docker build \
  --build-arg APP_VERSION=$APP_VERSION \
  --build-arg DB_HOST=$DB_HOST \
  --build-arg API_KEY=$API_KEY \
  -t myapp:latest .

Make it executable:

chmod +x build.sh

Then build with just:

./build.sh

You can even add command-line arguments to the script to make it dynamic (e.g., pass a version number when running the script).

内容的提问来源于stack exchange，提问作者Jay Jung