9f82b75e57
* removed packer.Cache and references since packer.Cache is never used except in the download step. The download step now uses the new func packer.CachePath(targetPath) for this, the behavior is the same. * removed download code from packer that was reimplemented into the go-getter library: progress bar, http download restart, checksuming from file, skip already downloaded files, symlinking, make a download cancellable by context. * on windows if packer is running without symlinking rights and we are getting a local file, the file will be copied instead to avoid errors. * added unit tests for step_download that are now CI tested on windows, mac & linux. * files are now downloaded under cache dir `sha1(filename + "?checksum=" + checksum) + file_extension` * since the output dir is based on the source url and the checksum, when the checksum fails, the file is auto deleted. * a download file is protected and locked by a file lock, * updated docs * updated go modules and vendors |
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| .. | ||
| .gitignore | ||
| .travis.yml | ||
| LICENSE | ||
| README.md | ||
| appveyor.yml | ||
| errors.go | ||
| stack.go | ||
README.md
errors 
Package errors provides simple error handling primitives.
go get github.com/pkg/errors
The traditional error handling idiom in Go is roughly akin to
if err != nil {
return err
}
which applied recursively up the call stack results in error reports without context or debugging information. The errors package allows programmers to add context to the failure path in their code in a way that does not destroy the original value of the error.
Adding context to an error
The errors.Wrap function returns a new error that adds context to the original error. For example
_, err := ioutil.ReadAll(r)
if err != nil {
return errors.Wrap(err, "read failed")
}
Retrieving the cause of an error
Using errors.Wrap constructs a stack of errors, adding context to the preceding error. Depending on the nature of the error it may be necessary to reverse the operation of errors.Wrap to retrieve the original error for inspection. Any error value which implements this interface can be inspected by errors.Cause.
type causer interface {
Cause() error
}
errors.Cause will recursively retrieve the topmost error which does not implement causer, which is assumed to be the original cause. For example:
switch err := errors.Cause(err).(type) {
case *MyError:
// handle specifically
default:
// unknown error
}
Read the package documentation for more information.
Contributing
We welcome pull requests, bug fixes and issue reports. With that said, the bar for adding new symbols to this package is intentionally set high.
Before proposing a change, please discuss your change by raising an issue.
License
BSD-2-Clause