open-nomad/vendor/github.com/hashicorp/go-getter/get.go

136 lines
3.7 KiB
Go

// getter is a package for downloading files or directories from a variety of
// protocols.
//
// getter is unique in its ability to download both directories and files.
// It also detects certain source strings to be protocol-specific URLs. For
// example, "github.com/hashicorp/go-getter" would turn into a Git URL and
// use the Git protocol.
//
// Protocols and detectors are extensible.
//
// To get started, see Client.
package getter
import (
"bytes"
"fmt"
"net/url"
"os/exec"
"regexp"
"syscall"
)
// Getter defines the interface that schemes must implement to download
// things.
type Getter interface {
// Get downloads the given URL into the given directory. This always
// assumes that we're updating and gets the latest version that it can.
//
// The directory may already exist (if we're updating). If it is in a
// format that isn't understood, an error should be returned. Get shouldn't
// simply nuke the directory.
Get(string, *url.URL) error
// GetFile downloads the give URL into the given path. The URL must
// reference a single file. If possible, the Getter should check if
// the remote end contains the same file and no-op this operation.
GetFile(string, *url.URL) error
}
// Getters is the mapping of scheme to the Getter implementation that will
// be used to get a dependency.
var Getters map[string]Getter
// forcedRegexp is the regular expression that finds forced getters. This
// syntax is schema::url, example: git::https://foo.com
var forcedRegexp = regexp.MustCompile(`^([A-Za-z0-9]+)::(.+)$`)
func init() {
httpGetter := new(HttpGetter)
Getters = map[string]Getter{
"file": new(FileGetter),
"git": new(GitGetter),
"hg": new(HgGetter),
"s3": new(S3Getter),
"http": httpGetter,
"https": httpGetter,
}
}
// Get downloads the directory specified by src into the folder specified by
// dst. If dst already exists, Get will attempt to update it.
//
// src is a URL, whereas dst is always just a file path to a folder. This
// folder doesn't need to exist. It will be created if it doesn't exist.
func Get(dst, src string) error {
return (&Client{
Src: src,
Dst: dst,
Dir: true,
Getters: Getters,
}).Get()
}
// GetAny downloads a URL into the given destination. Unlike Get or
// GetFile, both directories and files are supported.
//
// dst must be a directory. If src is a file, it will be downloaded
// into dst with the basename of the URL. If src is a directory or
// archive, it will be unpacked directly into dst.
func GetAny(dst, src string) error {
return (&Client{
Src: src,
Dst: dst,
Mode: ClientModeAny,
Getters: Getters,
}).Get()
}
// GetFile downloads the file specified by src into the path specified by
// dst.
func GetFile(dst, src string) error {
return (&Client{
Src: src,
Dst: dst,
Dir: false,
Getters: Getters,
}).Get()
}
// getRunCommand is a helper that will run a command and capture the output
// in the case an error happens.
func getRunCommand(cmd *exec.Cmd) error {
var buf bytes.Buffer
cmd.Stdout = &buf
cmd.Stderr = &buf
err := cmd.Run()
if err == nil {
return nil
}
if exiterr, ok := err.(*exec.ExitError); ok {
// The program has exited with an exit code != 0
if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
return fmt.Errorf(
"%s exited with %d: %s",
cmd.Path,
status.ExitStatus(),
buf.String())
}
}
return fmt.Errorf("error running %s: %s", cmd.Path, buf.String())
}
// getForcedGetter takes a source and returns the tuple of the forced
// getter and the raw URL (without the force syntax).
func getForcedGetter(src string) (string, string) {
var forced string
if ms := forcedRegexp.FindStringSubmatch(src); ms != nil {
forced = ms[1]
src = ms[2]
}
return forced, src
}