Plugin run does not fail on returned docker error

[timkral]

I mistakenly attempted a docker:push for a non-existent image and I noticed that my build did not fail (even though the docker logs showed an error):

[INFO] DOCKER> ... The push refers to a repository [yespath/motor] (len: 0)
14-May-2015 16:04:10    [ERROR] DOCKER> No such id: yespath/motor
14-May-2015 16:04:10    [INFO] DOCKER> ... The push refers to a repository [yespath/motor] (len: 1)
14-May-2015 16:04:10    [ERROR] DOCKER> No such id: yespath/motor
14-May-2015 16:04:10    [INFO] DOCKER> ... The push refers to a repository [yespath/motor] (len: 1)
14-May-2015 16:04:10    [ERROR] DOCKER> No such id: yespath/motor
14-May-2015 16:04:10    [INFO] DOCKER> ... The push refers to a repository [yespath/motor] (len: 1)
14-May-2015 16:04:10    [ERROR] DOCKER> No such id: yespath/motor
14-May-2015 16:04:10    [INFO] ------------------------------------------------------------------------
14-May-2015 16:04:10    [INFO] BUILD SUCCESS
14-May-2015 16:04:10    [INFO] ------------------------------------------------------------------------
14-May-2015 16:04:10    [INFO] Total time: 22.127 s
14-May-2015 16:04:10    [INFO] Finished at: 2015-05-14T23:04:10+00:00
14-May-2015 16:04:11    [INFO] Final Memory: 16M/185M
14-May-2015 16:04:11    [INFO] ------------------------------------------------------------------------
14-May-2015 16:04:11    Finished task 'Docker deploy' with result: Success

I tried testing the docker remote API directly (both v1.14 and v1.17) and I noticed that it returns a 200 status code in this case:

curl -v -X POST -L --post301 -H "X-Registry-Auth : XXXX" http://localhost:4243/images/doesnotexist/push* Hostname was NOT found in DNS cache
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 4243 (#0)
> POST /images/doesnotexist/push HTTP/1.1
> User-Agent: curl/7.35.0
> Host: localhost:4243
> Accept: */*
> X-Registry-Auth : XXXX
> 
< HTTP/1.1 200 OK
< Content-Type: application/json
< Date: Thu, 14 May 2015 23:43:30 GMT
< Transfer-Encoding: chunked
< 
{"status":"The push refers to a repository [doesnotexist] (len: 0)"}
{"errorDetail":{"message":"could not find image: no such id: doesnotexist"},"error":"could not find image: no such id: doesnotexist"}

So it seems that simply examining the response status code is not sufficient to determine if the request was successful or not.

For what it's worth, I think this is kind of a poor API contract. But still, it's disconcerting to see docker errors and a successful build.