Command Execution Flow

Overview:

The docker command is a versatile tool for managing Docker containers, images, and networks. This document outlines the flow of a Docker command, from parsing arguments and options to interacting with the docker daemon and displaying results.

Command Parsing and Option Handling:

The docker command uses Cobra library (https://github.com/spf13/cobra) for parsing arguments and options.

Example:

docker run -it -p 80:80 nginx:latest
          

In this example, docker is the command, run is the subcommand, and -it, -p 80:80, and nginx:latest are options and arguments.

Command Execution:

The parsed arguments and options are then used to determine the appropriate command to execute. The command is then executed by calling the corresponding function in the docker CLI package.

Example:

The docker run command is handled by the run function in cmd/run/run.go (cmd/run/run.go).

Docker API Interaction:

Once a command is executed, it often interacts with the docker daemon via the Docker API (https://docs.docker.com/engine/api/v1.41/).

Example:

The docker run command sends a POST request to the docker daemon’s /containers/create endpoint (https://docs.docker.com/engine/api/v1.41/#operation/ContainerCreate) to create a new container.

Result Display:

The response from the docker daemon is then processed and displayed to the user.

Example:

The docker ps command displays a list of running containers.

Key Components:

• docker CLI package: Contains the main CLI entry point and various commands.
• Cobra library: Used for parsing arguments and options.
• Docker API: Used for communication between the docker CLI and the docker daemon.

Note:

The command execution flow may vary depending on the specific command. Refer to the relevant code files in the docker CLI repository for detailed information.