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
This is more aligned with `Daemon.GetImage` and less confusing.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Upstream-commit: d7d512bb927023b76c3c01f54a3655ee7c341637
Component: engine
Remove double reference between containers and exec configurations by
keeping only the container id.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Upstream-commit: 9ca2e4e81cdb950f2b5958a7712153d1a6dd6e4c
Component: engine
It'll allow to separate daemon layer more cleanly later.
Signed-off-by: Alexander Morozov <lk4d4@docker.com>
Upstream-commit: bb0e7eb196c65972ea66154461b7e654d776f92a
Component: engine
Create a supervisor interface to let the container monitor to emit events.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Upstream-commit: ca5ede2d0a23cb84cac3b863c363d0269e6438df
Component: engine
Although having a request ID available throughout the codebase is very
valuable, the impact of requiring a Context as an argument to every
function in the codepath of an API request, is too significant and was
not properly understood at the time of the review.
Furthermore, mixing API-layer code with non-API-layer code makes the
latter usable only by API-layer code (one that has a notion of Context).
This reverts commit de4164043546d2b9ee3bf323dbc41f4979c84480, reversing
changes made to 7daeecd42d7bb112bfe01532c8c9a962bb0c7967.
Signed-off-by: Tibor Vass <tibor@docker.com>
Conflicts:
api/server/container.go
builder/internals.go
daemon/container_unix.go
daemon/create.go
Upstream-commit: b08f071e18043abe8ce15f56826d38dd26bedb78
Component: engine
This PR adds a "request ID" to each event generated, the 'docker events'
stream now looks like this:
```
2015-09-10T15:02:50.000000000-07:00 [reqid: c01e3534ddca] de7c5d4ca927253cf4e978ee9c4545161e406e9b5a14617efb52c658b249174a: (from ubuntu) create
```
Note the `[reqID: c01e3534ddca]` part, that's new.
Each HTTP request will generate its own unique ID. So, if you do a
`docker build` you'll see a series of events all with the same reqID.
This allow for log processing tools to determine which events are all related
to the same http request.
I didn't propigate the context to all possible funcs in the daemon,
I decided to just do the ones that needed it in order to get the reqID
into the events. I'd like to have people review this direction first, and
if we're ok with it then I'll make sure we're consistent about when
we pass around the context - IOW, make sure that all funcs at the same level
have a context passed in even if they don't call the log funcs - this will
ensure we're consistent w/o passing it around for all calls unnecessarily.
ping @icecrime @calavera @crosbymichael
Signed-off-by: Doug Davis <dug@us.ibm.com>
Upstream-commit: 26b1064967d9fcefd4c35f60e96bf6d7c9a3b5f8
Component: engine
- some method names were changed to have a 'Locking' suffix, as the
downcased versions already existed, and the existing functions simply
had locks around the already downcased version.
- deleting unused functions
- package comment
- magic numbers replaced by golang constants
- comments all over
Signed-off-by: Morgan Bauer <mbauer@us.ibm.com>
Upstream-commit: abd72d4008dde7ee8249170d49eb4bc963c51e24
Component: engine
1. /container/<name>/exec - Creates a new exec command instance in the daemon and container '<name>'. Returns an unique ID for each exec command.
2. /exec/<name>/start - Starts an existing exec command instance. Removes the exec command from the daemon once it completes.
Adding /exec/<name>/resize to resize tty session of an exec command.
Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Upstream-commit: bfebdfde78753f85d53d62634654de0b80f6872d
Component: engine
This is part of an effort to break apart the deprecated server/ package
Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Upstream-commit: e0fd96f850a65cfa6b386fb6b91ee8ced58f5fc2
Component: engine
