76 lines
2.0 KiB
Go
76 lines
2.0 KiB
Go
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// The packer package contains the core components of Packer.
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package packer
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import "os"
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// A command is a runnable sub-command of the `packer` application.
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// When `packer` is called with the proper subcommand, this will be
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// called.
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//
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// The mapping of command names to command interfaces is in the
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// Environment struct.
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type Command interface {
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Run(env *Environment, args []string) int
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}
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// The environment struct contains all the state necessary for a single
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// instance of Packer.
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//
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// It is *not* a singleton, but generally a single environment is created
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// when Packer starts running to represent that Packer run. Technically,
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// if you're building a custom Packer binary, you could instantiate multiple
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// environments and run them in parallel.
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type Environment struct {
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command map[string]Command
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ui Ui
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}
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// This creates a new environment
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func NewEnvironment() *Environment {
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env := &Environment{}
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env.command = make(map[string]Command)
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env.command["version"] = new(versionCommand)
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env.ui = &ReaderWriterUi{ os.Stdin, os.Stdout }
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return env
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}
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// Executes a command as if it was typed on the command-line interface.
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// The return value is the exit code of the command.
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func (e *Environment) Cli(args []string) int {
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if len(args) == 0 {
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e.PrintHelp()
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return 1
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}
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command, ok := e.command[args[0]]
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if !ok {
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// The command was not found. In this case, let's go through
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// the arguments and see if the user is requesting the version.
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for _, arg := range args {
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if arg == "--version" || arg == "-v" {
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command = e.command["version"]
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break
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}
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}
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// If we still don't have a command, show the help.
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if command == nil {
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e.PrintHelp()
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return 1
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}
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}
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return command.Run(e, args)
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}
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// Returns the UI for the environment. The UI is the interface that should
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// be used for all communication with the outside world.
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func (e *Environment) Ui() Ui {
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return e.ui
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}
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// Prints the CLI help to the UI.
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func (e *Environment) PrintHelp() {
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e.ui.Say("Bad.\n")
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}
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