Debugging why Nexus Repository 2 cannot find an artifact (?describe)

Visit my.sonatype.com for documentation on Nexus Repository version 2.

If you are unable to find an artifact that you just know is there locally in your Nexus Repository 2, the most likely causes of failure are:

1. The proxy repository containing the artifact is not in your group repository
2. The download was blocked by a routing rule

Nexus Repository 2 provides a tool to debug the process used to resolve an artifact.  If you want to see information about how Nexus is finding ( or not finding ) artifacts, put the URL of the artifact that Maven is trying to download into a browser and add

?describe

to the end of it, like this: 

http://localhost:8081/nexus/content/groups/public/foo/bar/1.0/bar-1.0.jar?describe

Instead of returning the artifact, Nexus will return debug output which can answer questions like

• where Nexus Repository 2 looked for an artifact
• if the artifact could not be found and why
• when the artifact is found, statistics about the process used to find the artifact.

Tip: Check the "processedRepositoriesList" and "appliedMappings" respectively in the output.

Here we see an example output showing that the artifact was not found due to an exclusive routing rule for "./project/."  (Note that the repositories searched are also listed):

{
  "data":{
    "requestUrl":"http://localhost:8081/nexus/content/groups/public/test/project/1.0/project-1.0.jar?describe",
    "processingTimeMillis":471,
    "request":{
      "requestUrl":"http://localhost:8081/nexus/content
 /groups/public/test/project/1.0/project-1.0.jar?describe",
      "requestPath":"/test/project/1.0/project-1.0.jar",
      "requestContext":[
        "request.received.timestamp=1276286536595",
        "request.address=0:0:0:0:0:0:0:1%0",
        "request.remoteOnly=false",
        "request.url=http://localhost:8081/nexus/content/groups/public/test/project/1.0/project-
 1.0.jar?describe",
        "request.localOnly=false",
        "request.appRootUrl=http://localhost:8081/nexus"
      ]
    },
    "response":{
      "responseType":"NOT_FOUND",
      "processedRepositoriesList":[
        "public",
        "snapshots",
        "thirdparty",
        "central",
        "java.net-m2",
        "java.net-m1-m2",
        "google",
        "apache-snapshots",
        "codehaus-snapshots"
      ],
      "appliedMappings":[
        "public repository applied [11b647d6117038d8=
 [type=EXCLUSION, groupId=public, patterns=[.*/project/.*], mappedRepositories=[releases]]]"
      ]
    }
  }
}