| Carsten Ziegeler | db30186 | 2011-11-18 09:40:49 +0000 | [diff] [blame] | 1 | OSGi Service Diagnostics and WebConsole Plugin |
| 2 | ============================================== |
| 3 | |
| Arjun Panday | 0462b39 | 2012-11-07 18:55:10 +0000 | [diff] [blame] | 4 | This projects aims at easing diagnostics of OSGi services and finding about missing and/or circular dependencies. |
| Carsten Ziegeler | db30186 | 2011-11-18 09:40:49 +0000 | [diff] [blame] | 5 | |
| 6 | Typically in a large system with many cascading dependencies managed by different trackers such as DeclarativeService, DependencyManager or others, tracking the root cause of a top level service not being started can become very cumbersome. When building service oriented architectures, it is often the case that a single missing requirement will lock a full stack of services, but to find that one requirement is like finding a needle in a haystack! |
| 7 | |
| 8 | The basic idea here is to ask each dependency manager instance about its unresolved dependencies, merge all answers and filter the result to keep only the root causes. |
| 9 | |
| 10 | Typically, if A depends on B which depends on C which depends on D, and D is nowhere to be found, I need only show the "C -> D" missing requirement; if D is resolved, then the whole stack is unlocked. |
| 11 | |
| 12 | Similarly, if D is known by another dependency management system, but unregistered because it depends on E which is missing, then only the "D -> E" requirement is relevant. |
| 13 | |
| 14 | Project organization (core): |
| 15 | ============================ |
| 16 | * servicediagnostics: the API package. It holds the main service interface as well as the plugin interface, to extend to other dependency management systems |
| 17 | |
| 18 | * servicediagnostics.impl: the implementation package. It contains plugins implementations for org.apache.felix.scr and org.apache.felix.dependencymanager, as well as the main service implementation. |
| 19 | |
| 20 | * servicediagnostics.webconsole: a Felix WebConsole plugin that displays a graphical view of the diagnostics result. Alternatively it can also show a graph of all services currently registered in the service registry and the bundles using them. See Screenshot-notavail.png and Screenshot-all.png. |
| 21 | |
| 22 | The "sample" part simply contains some test classes and a helper class to launch Felix. |
| 23 | |
| 24 | How to build the project: |
| 25 | ========================= |
| 26 | |
| 27 | > mvn install |
| 28 | |
| 29 | How to run: |
| 30 | =========== |
| 31 | I'm providing a simple run script just to try out the service. |
| Carsten Ziegeler | db30186 | 2011-11-18 09:40:49 +0000 | [diff] [blame] | 32 | > ./run.sh |
| 33 | |
| 34 | It should display: |
| 35 | [INFO] Started jetty 6.1.x at port(s) HTTP:8080 |
| 36 | |
| 37 | You can then point your browser to |
| 38 | http://localhost:8080/system/console/servicegraph |
| 39 | |
| 40 | (login/password is admin/admin) |
| 41 | then click on either "Unavail" or "All". |
| 42 | The "bubbles" can be dragged around for better readability. The colors are random and don't mean anything. |
| 43 | On the "All" view, arrows point from bundles to the services they use. |
| 44 | On the "Unavail" view, arrows point from a leaf component to its missing dependencies. |
| 45 | |
| 46 | (note: the lib directory is provided for dependencies that are not readily available as OSGi bundles from maven) |
| 47 | |
| 48 | Issues & TODOs: |
| 49 | =============== |
| 50 | * use of JSONObject in Servlet.scala is a bit awkward, but Scala's native json is still incomplete.. |
| Carsten Ziegeler | db30186 | 2011-11-18 09:40:49 +0000 | [diff] [blame] | 51 | * no support for iPojo, Blueprint, basic ServiceTrackers... more plugins could be developed. I only wrote the ones i'm using. |