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<a href="https://community.jboss.org/index.jspa" style="text-decoration: none; color: #E1E1E1">JBoss Community</a></h1>
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Single Installation Patching
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new comment by <a href="https://community.jboss.org/people/jmesnil">Jeff Mesnil</a> <a href="https://community.jboss.org/docs/DOC-47500#comment-11114">View all comments on this document</a>
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<div class="jive-rendered-content"><p>I have been working on the patch CLI command to patch an AS7 installation and add to tweak the code related to module to be able to generate a correct patch generated by diffing 2 AS7 installations.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>When comparing modules to check whether they have been updated, computing the dir's checksum is not correct:</p><p>* Jar files generated during AS7 build can not have the same checksum since the creation date of the class files is store in the jar's zip entries.</p><p>=> this concerns AS7's own modules (org/jboss/as/...) and also jandex jars for 3rd party libraries</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>To circumvent that, instead of computing the SHA-1 of the jar files, I compute the checksum of the file's zip entries name/size/crc (ie I exclude the date metadata).</p><p>I also need to exclude some entries from the jar:</p><p>* Some java sources are generated at build time (logger and bundle classes) and embed their generation date into the code => the .class files have different size and crc</p><p>* META-INF/MANIFEST.MF and pom.properties files also contains the jar creation date => these files have different size and crc</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>When a module dir is compared, .index files (generated at runtime) should not be taken into account (they are not present in the pristine AS7 installations I used to generate the patch by diff)</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I have a branch for this[1] which uses the same hash algo (based on the zip entries metadata) for all jars. This could likely be reduced only to jars in org/jboss/as and -jandex.jar.</p><p>With these changes, the patch code is able to compute a "suitable" checksum for module.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I also think the module's resource checksum should be based on the content of the module.xml. Only resources listed in the <resources> element should be included in the checksum. Eg adding a README to a module should not change its checksum. This means a 2-step check:</p><p>1. check that the module.xml are identical (with a file checksum)</p><p>2. check that the resources listed by the module are "equivalent" (with jar-specific checksum for jar + file checksum for other resources)</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>What do you think?</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>[1] <a class="jive-link-external-small" href="https://github.com/jmesnil/jboss-as/compare/emuckenhuber:patches-master...patches_module_checksum">https://github.com/jmesnil/jboss-as/compare/emuckenhuber:patches-master...patches_module_checksum</a></p></div>
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