Add native hints#648
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In order to let any Java project including PebbleTemplates as a dependency to be able to build and run a native image using the AOT-compiler GraalVM, it is necessary to add native hints to the GraalVM so that it can maintain class and variables information during compile time (and consequently runtime) to be used as information for Reflection, Proxies and other JVM mechanisms. This will add the necessary TypeHints for the SpringBoot starter only, in order to enable the building of a project using Spring Boot as framework, and to promote further experiments with other frameworks.
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Proposed fix for #647 |
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Unfortunately, even with the added hints for the ForNode class, for the inner LoopVariable class, it is not possible to let the native image reach its fields due to the fact that it is a private class. So, even with the hints, we end up with a similar error to this one: 2023-03-18 00:29:24.390 -ERROR 1 --- [nio-7300-exec-3] o.a.c.c.C.[.[.[.[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [/api/planrepository] threw exception [Request processing failed: io.pebbletemplates.pebble.error.PebbleException: Could not perform addition (**template**:6)] with root cause
io.pebbletemplates.pebble.error.AttributeNotFoundException: Attribute [index] of [io.pebbletemplates.pebble.node.ForNode$LoopVariables] does not exist or can not be accessed and strict variables is set to true. (**template**:6)
at io.pebbletemplates.pebble.node.expression.GetAttributeExpression.evaluate(GetAttributeExpression.java:91) ~[native:na]
at io.pebbletemplates.pebble.node.expression.AddExpression.evaluate(AddExpression.java:22) ~[native:na]
at io.pebbletemplates.pebble.node.expression.FilterExpression.evaluate(FilterExpression.java:66) ~[native:na]
at io.pebbletemplates.pebble.node.PrintNode.render(PrintNode.java:37) ~[na:na]
at io.pebbletemplates.pebble.node.BodyNode.render(BodyNode.java:44) ~[native:na]
at io.pebbletemplates.pebble.node.ForNode.render(ForNode.java:125) ~[native:na]
at io.pebbletemplates.pebble.node.BodyNode.render(BodyNode.java:44) ~[native:na]
at io.pebbletemplates.pebble.node.RootNode.render(RootNode.java:31) ~[na:na]
at io.pebbletemplates.pebble.template.PebbleTemplateImpl.evaluate(PebbleTemplateImpl.java:157) ~[native:na]
at io.pebbletemplates.pebble.template.PebbleTemplateImpl.evaluate(PebbleTemplateImpl.java:96) ~[native:na]Is there any way to solve this? |
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Never had the chance to try GraalVM. Can't help you on that one |
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I haven't tested it but I wanted to one day now that it works out of the box on Spring boot. @noblehelm Were you able to work around the problem? If you override the class by creating in your project ,the same class file in the same package (ugly but works), and make it public, does that solve the problem? |
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I've managed to make it work by transforming the LoopVariable class into an immutable class/object, with private fields and its respective Getters, and making it public instead of private. Then, it was just a jump over into adding the apropriate type hint for the LoopVariable and everything worked. I've pushed a new commit to the PR, will do a squash if required. |
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Ok let me know when you are done testing |
Upon tests made based on the native-image.peb resource file, only the inner LoopVariable class and the UnaryMinusExpression actually required the type hint for the native image generation to work. The rest worked out of the box for the spring-boot module.
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I've finished the tests and included the resource file Upon tests, the only expression that actually required the type hint was the UnaryMinus. All of the rest worked out-of-the-box with the Spring integration. So, I removed the code in order to reflect only what is actually needed. If sometime in the future another expression is to be added, maybe a type hint can be added there IF it does require the hint. Otherwise, there is no necessity to do it. |
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If you wish, I can squash the commits before merge. |
Include missing test examples
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Any updates? |
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Thanks ! Will try to do a release soon ! |
In order to let any Java project including PebbleTemplates as a dependency to be able to build and run a native image using the AOT-compiler GraalVM, it is necessary to add native hints to the GraalVM so that it can maintain class and variables information during compile time (and consequently runtime) to be used as information for Reflection, Proxies and other JVM mechanisms.
This will add the necessary TypeHints for the SpringBoot starter only, in order to enable the building of a project using Spring Boot as framework, and to promote further experiments with other frameworks.