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>
This will allow us to have a windows-to-linux CI, where the linux host
can be anywhere, connecting with TLS.
Signed-off-by: Tibor Vass <tibor@docker.com>
Attempt layer mounts from up to 3 source repositories, possibly
falling back to a standard blob upload for cross repository pushes.
Addresses compatiblity issues with token servers which do not grant
multiple repository scopes, resulting in an authentication failure for
layer mounts, which would otherwise cause the push to terminate with an
error.
Signed-off-by: Brian Bland <brian.bland@docker.com>
In cases where the a plugin responds with both a null or empty volume
and a null or empty Err, the daemon would panic.
This is because we assumed the idiom if `err` is nil, then `v` must not
be but in reality the plugin may return whatever it wants and we want to
make sure it doesn't harm the daemon.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
If cgroup swap memory limit isn't enabled, then
the -m flag doesn't work and the container that is created for
both of these tests is very large. Because we are trying to run the
containers out of memory, this takes a very long time and causes the
tests to fail most of the time.
Follow-up to #17913
Signed-off-by: Christopher Jones <tophj@linux.vnet.ibm.com>
The container started with `-d` as part of the test requires a `waitRun`
to ensure it is actually running before attempting any other operation.
Signed-off-by: Arnaud Porterie <arnaud.porterie@docker.com>
- Allow to filter containers by volume with `--filter volume=name` and `filter volume=/dest`.
- Show their names in the list with the custom format `{{ .Mounts }}`.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Now that the various fixes are all committed, let's see if this gets
less flaky now.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Add `--restart` flag for `update` command, so we can change restart
policy for a container no matter it's running or stopped.
Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
The restarts in the authz plugin test suite seems to be causing
flakiness in CI, and can be avoided by separating the daemon start and
busybox image load.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Arnaud Porterie
David Calavera
Brian Goff
Sebastiaan van Stijn
Riyaz Faizullabhoy
Tibor Vass
Tibor Vass
Vincent Demeester
John Howard
Brian Bland
Lei Jitang
Qiang Huang
Christopher Jones
Wen Cheng Ma
Stefan Weil
Phil Estes
Antonio Murdaca
Zhang Wei
Antonio Murdaca