Example resolving dynamic versions with ivy on Sonatype Nexus 3

introduction

Nexus 3 is missing a feature, to list artifacts or folders by just using suburls of the final artifact. Nexus 2 had this feature and the project here is a minimal apache ant/ivy example to demonstrate effects of the changed behavior.

problem

If ivy is resolving dynamic versions from a maven repository it usually reads a maven-metadata.xml file (which should contain all available versions).

The problem with ivy is, that itself does not create or update the maven-metadata.xml (see this posting). This way one either have to rely on scheduled tasks of the repository manager, on the price of timing issues. New artifact versions may not be found immediately after being uploaded or SNAPSHOT versions are not correctly identified as changed and become obsolete in local caches.

The solution to this problem is to tell ivys ibiblio resolver to useMavenMetadata="false" (see this blog).

effect

Resolving dynamic versions - such as commons-logging:commons-logging:1.+ - from Nexus 2 works just fine:

...
[ivy:resolve] == resolving dependencies #;working@NBDR246->commons-logging#commons-logging;1.+ [default->compile]
[ivy:resolve] default-cache: no cached resolved revision for commons-logging#commons-logging;1.+
[ivy:resolve]           tried https://repo1.maven.org/maven2/commons-logging/commons-logging/[revision]/commons-logging-[revision].pom
[ivy:resolve] Execution environment profile JavaSE-1.2 loaded
...

while it does not with a Nexus 3 repository manager:

...
[ivy:resolve] default-cache: no cached resolved revision for commons-logging#commons-logging;1.+
[ivy:resolve]           tried http://localhost:8081/repository/maven-public/commons-logging/commons-logging/[revision]/commons-logging-[revision].pom

[ivy:resolve]           tried http://localhost:8081/repository/maven-public/commons-logging/commons-logging/[revision]/commons-logging-[revision].jar

[ivy:resolve]   ibiblio: no ivy file nor artifact found for commons-logging#commons-logging;1.+
[ivy:resolve] WARN:     module not found: commons-logging#commons-logging;1.+
[ivy:resolve] WARN: ==== ibiblio: tried
[ivy:resolve] WARN:   http://localhost:8081/repository/maven-public/commons-logging/commons-logging/[revision]/commons-logging-[revision].pom
[ivy:resolve] WARN:   -- artifact commons-logging#commons-logging;1.+!commons-logging.jar:
[ivy:resolve] WARN:   http://localhost:8081/repository/maven-public/commons-logging/commons-logging/[revision]/commons-logging-[revision].jar
[ivy:resolve]   resolved ivy file produced in cache
[ivy:resolve] :: downloading artifacts ::
[ivy:resolve] :: resolution report :: resolve 85ms :: artifacts dl 0ms
        ---------------------------------------------------------------------
        |                  |            modules            ||   artifacts   |
        |       conf       | number| search|dwnlded|evicted|| number|dwnlded|
        ---------------------------------------------------------------------
        |      default     |   1   |   0   |   0   |   0   ||   0   |   0   |
        ---------------------------------------------------------------------
[ivy:resolve] WARN:     ::::::::::::::::::::::::::::::::::::::::::::::
[ivy:resolve] WARN:     ::          UNRESOLVED DEPENDENCIES         ::
[ivy:resolve] WARN:     ::::::::::::::::::::::::::::::::::::::::::::::
[ivy:resolve] WARN:     :: commons-logging#commons-logging;1.+: not found
[ivy:resolve] WARN:     ::::::::::::::::::::::::::::::::::::::::::::::
...

running the example

The following command can be used to reproduce the described effects (a running ant installation is required, ivy will be downloaded):

# maven central url
ant resolve-dynamic-central
# local nexus 3 url (default installation)
ant resolve-dynamic-local
# individual repository base-url
ant resolve-dynamic -Divy.repository.url=<url>