Moving all strings to the errors package wasn't a good idea after all.
Our custom implementation of Go errors predates everything that's nice
and good about working with errors in Go. Take as an example what we
have to do to get an error message:
```go
func GetErrorMessage(err error) string {
switch err.(type) {
case errcode.Error:
e, _ := err.(errcode.Error)
return e.Message
case errcode.ErrorCode:
ec, _ := err.(errcode.ErrorCode)
return ec.Message()
default:
return err.Error()
}
}
```
This goes against every good practice for Go development. The language already provides a simple, intuitive and standard way to get error messages, that is calling the `Error()` method from an error. Reinventing the error interface is a mistake.
Our custom implementation also makes very hard to reason about errors, another nice thing about Go. I found several (>10) error declarations that we don't use anywhere. This is a clear sign about how little we know about the errors we return. I also found several error usages where the number of arguments was different than the parameters declared in the error, another clear example of how difficult is to reason about errors.
Moreover, our custom implementation didn't really make easier for people to return custom HTTP status code depending on the errors. Again, it's hard to reason about when to set custom codes and how. Take an example what we have to do to extract the message and status code from an error before returning a response from the API:
```go
switch err.(type) {
case errcode.ErrorCode:
daError, _ := err.(errcode.ErrorCode)
statusCode = daError.Descriptor().HTTPStatusCode
errMsg = daError.Message()
case errcode.Error:
// For reference, if you're looking for a particular error
// then you can do something like :
// import ( derr "github.com/docker/docker/errors" )
// if daError.ErrorCode() == derr.ErrorCodeNoSuchContainer { ... }
daError, _ := err.(errcode.Error)
statusCode = daError.ErrorCode().Descriptor().HTTPStatusCode
errMsg = daError.Message
default:
// This part of will be removed once we've
// converted everything over to use the errcode package
// FIXME: this is brittle and should not be necessary.
// If we need to differentiate between different possible error types,
// we should create appropriate error types with clearly defined meaning
errStr := strings.ToLower(err.Error())
for keyword, status := range map[string]int{
"not found": http.StatusNotFound,
"no such": http.StatusNotFound,
"bad parameter": http.StatusBadRequest,
"conflict": http.StatusConflict,
"impossible": http.StatusNotAcceptable,
"wrong login/password": http.StatusUnauthorized,
"hasn't been activated": http.StatusForbidden,
} {
if strings.Contains(errStr, keyword) {
statusCode = status
break
}
}
}
```
You can notice two things in that code:
1. We have to explain how errors work, because our implementation goes against how easy to use Go errors are.
2. At no moment we arrived to remove that `switch` statement that was the original reason to use our custom implementation.
This change removes all our status errors from the errors package and puts them back in their specific contexts.
IT puts the messages back with their contexts. That way, we know right away when errors used and how to generate their messages.
It uses custom interfaces to reason about errors. Errors that need to response with a custom status code MUST implementent this simple interface:
```go
type errorWithStatus interface {
HTTPErrorStatusCode() int
}
```
This interface is very straightforward to implement. It also preserves Go errors real behavior, getting the message is as simple as using the `Error()` method.
I included helper functions to generate errors that use custom status code in `errors/errors.go`.
By doing this, we remove the hard dependency we have eeverywhere to our custom errors package. Yes, you can use it as a helper to generate error, but it's still very easy to generate errors without it.
Please, read this fantastic blog post about errors in Go: http://dave.cheney.net/2014/12/24/inspecting-errors
Signed-off-by: David Calavera <david.calavera@gmail.com>
Upstream-commit: a793564b2591035aec5412fbcbcccf220c773a4c
Component: engine
dockerinit has been around for a very long time. It was originally used
as a way for us to do configuration for LXC containers once the
container had started. LXC is no longer supported, and /.dockerinit has
been dead code for quite a while. This removes all code and references
in code to dockerinit.
Signed-off-by: Aleksa Sarai <asarai@suse.com>
Upstream-commit: 4357ed4a7363a1032edf93cf03232953c805184f
Component: engine
docker's network disconnect api now supports `Force` option which can be
used to force cleanup an endpoint from any host in the cluster.
Signed-off-by: Madhu Venugopal <madhu@docker.com>
Upstream-commit: b464f1d78cdfa2a4124e083b8f7b0f2353f12de3
Component: engine
RWLayer will now have more operations and be protected through a referenced type rather than always looked up by string in the layer store.
Separates creation of RWLayer (write capture layer) from mounting of the layer.
This allows mount labels to be applied after creation and allowing RWLayer objects to have the same lifespan as a container without performance regressions from requiring mount.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Upstream-commit: d04fa49a0dec89d2f71a813ce8eaa182184139c5
Component: engine
- Make the API client library completely standalone.
- Move windows partition isolation detection to the client, so the
driver doesn't use external types.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Upstream-commit: 7ac4232e70fe7cf7318333cd0890db7f95663079
Component: engine
Add function to get metadata from layer store for a mutable layer
fixes#18614
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
Upstream-commit: a7e096832123280d26df3c121ecad8dd012060b9
Component: engine
To make docker inspect return a consistent result of networksettings
for created container and stopped container, it's bettew to update
the network settings on container creating.
Signed-off-by: Lei Jitang <leijitang@huawei.com>
Upstream-commit: c427131c94369d5c49a4f14d78e6ab9c678e12df
Component: engine
So other packages don't need to import the daemon package when they
want to use this struct.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Signed-off-by: Tibor Vass <tibor@docker.com>
Upstream-commit: 6bb0d1816acd8d4f7a542a6aac047da2b874f476
Component: engine
