Eric Helgeson

Posted on May 17, 2019 Edited on Jul 23, 2020

Grails 4 Upgrade Notes

#grails #groovy #micronaut #webdev

Grails 4 is the next iteration of the Grails web framework. Grails is a developer friendly framework built on top of Spring-boot, Groovy, and now Micronaut.

Status

Grails 4 is released!

I've ported a non-trivial app from Grails 3.3.9 to 4.0.0 as well as updated to JDK11. The total effort was only a few hours - welcome news to many who are upgrading.

Initial app startup time is about 15 seconds - 2x faster than the same app in Grails 3.3.9.

Reloading has changed and there are a few options. The default option is from spring-dev-tools - fast restart. This restarts your app faster then a normal restart, but still can be extremely slow for large projects.

Hot reloading options are JRebel - a paid option that works for JDK8/11 - or spring-loaded though it only supports JDK8 and is no longer maintained. Instructions for spring-loaded

IDE Support all works in Grails 4 (same as 3.3.9) - IntelliJ is still my recommended IDE for any Grails, Groovy, or Java developer.

Updates

There are tons of updates to Grails 4 and the frameworks it builds upon. Here's a list of updates and release notes you should review if you're updating your apps.

Grails 4
- Upgrade notes
- New app diff from 3.3.10 -> 4.0.0
Micronaut 1.1
Spring Boot 2.1
Spring 5.1
Groovy 2.5
Hibernate 5.3/5.4 support
Java 11

Install

SDKMan makes installing and managing a JVM and many frameworks a snap:

sdk install java 11.0.2-open
sdk install grails 4.0.3

Plugins

Plugins are an essential part of the Grails developer experience. Luckily many plugins that worked in Grails 3 work out of the box in Grails 4 - or with only slight modifications due.

Working Plugins

Spring-Security-Core 4.0.0
- New delegation password strategy:
- https://www.baeldung.com/spring-security-5-password-storage
- If you already used bcrypt can do it all at once too:
- UPDATE my_users SET password = CONCAT('{bcrypt}', password);
Spring-session-redis (boot starter)
- Updated dependencies

compile "org.springframework.boot:spring-boot-starter-data-redis"
compile "org.springframework.session:spring-session-data-redis"

Spring-Websocket

compile "org.grails.plugins:grails-spring-websocket:2.5.0.RC1"

Grails-Quartz

buildscript {
    dependencies {
        classpath 'org.grails.plugins:quartz:2.0.13' // Needed to compile *Job classes
    }
}

dependencies {
    compile 'org.grails.plugins:quartz:2.0.13'
    compile 'org.quartz-scheduler:quartz:2.2.1' // Is not pulled in by default
}

Database Migration Plugin 3.1.0.RC1
Asset-Pipeline 3.1.0
External Config
- Works - use RC1+

    compile 'org.grails.plugins:external-config:2.0.0'

Spring Security UI
- https://github.com/grails-plugins/grails-spring-security-ui/issues/111
Schwartz Plugin
- 2.0.0.RC1
Grails Cache Plugin
- 5.0.0.RC1
Spring Security OAuth2 Provider
- 4.0.0-RC1
Sentry
Grails Mail
- 3.0.0

Not working

Audit-Logging Plugin
- WIP @ https://github.com/robertoschwald/grails-audit-logging-plugin/pull/183

Resolved

~~Asset Pipeline Handlebars issue:~~
- Needed to update to change //= require handlebars/handlebars.js to //= require handlebars-runtime

2019-01-13 16:59:42.280  WARN --- [nio-8080-exec-1] asset.pipeline.DirectiveProcessor        : Unable to Locate Asset: /handlebars/handlebars.js
Warning: Nashorn engine is planned to be removed from a future JDK release

~~Gson Views~~
- Resolved.
- Unable to render json with simple objects (just get null response)
- Domain classes dont render:

  Model variable [someDomain] of with value [Description] type [com.x.SomeDomain] is not of the correct type [com.x.SomeDomain]. Stacktrace follows:

Opened Issue https://github.com/grails/grails-views/issues/202

Other notes Notes

Hot reload for JDK8 only
- spring-loaded supports only up to JDK8.
- Fast reload takes about 5-6 seconds (hopefully can improve)
org.grails:grails-datastore-rest-client no longer maintained
- Use a different http client such as
  - micronaut-http-client, http-builder-ng, feign, okhttp, etc
- Or use the old unmaintained GORM 6 version:

compile('org.grails:grails-datastore-rest-client:6.1.9.RELEASE'){
    exclude group:'org.grails', module:'grails-plugin-converters'
}

Groovy 2.5.x
- Doesn't include the Date Utils helpers by default - need to add them in.
- compile 'org.codehaus.groovy:groovy-dateutil'
- (Should just update to java.time.*)
- JDK 11 Warnings (expected)
- https://dev.to/erichelgeson/removing-illegal-reflective-access-warnings-in-grails-4-393o
- .pop() & collections behavior changed to align with Java - https://issues.apache.org/jira/browse/GROOVY-9388
Dependencies changes (Gradle 5.1)
- An issue where dependencies like com.jameskleeh:excel-builder - don't pull in their dependencies (eg: Apache POI)
Hibernate Deprecated warnings (expected)

Hibernate's legacy org.hibernate.Criteria API is deprecated; use the JPA javax.persistence.criteria.CriteriaQuery instead
// and
HHH020100: The Ehcache second-level cache provider for Hibernate is deprecated.  See https://hibernate.atlassian.net/browse/HHH-12441 for details.

Hide them in logback.groovy
- logger('org.hibernate.orm.deprecation', ERROR, ['STDOUT'], false)

Notes or tips of your own?

Join us over on the grails-community slack channel or comment below!

Top comments (10)

Robert Oschwald • Jul 15 '19

Grails Cache Plugin: Not working, yet. github.com/grails-plugins/grails-c...

Grails Schwartz Plugin: Not working, yet. github.com/agileorbit/grails-schwa...

Audit-Logging Plugin: Not working, yet. WIP. github.com/robertoschwald/grails-a...

Works:

Db-Migration Plugin: 3.1.0.RC1

Asset-Pipeline-Grails: 3.0.10

Eric Helgeson • Jul 15 '19

Updated with this list, thanks!

amit-pawar-rx • Jan 20 '20

@eric can you please help me to underdstand how to work with the resultTranformer() in UTC , its giving error with respect to criteria.

groovy.lang.MissingMethodException: No signature of method: grails.gorm.CriteriaBuilder.resultTransformer() is applicable for argument types: (org.hibernate.transform.AliasToEntityMapResultTransformer) values: [org.hibernate.transform.AliasToEntityMapResultTransformer@3213c334]
at org.grails.datastore.gorm.query.criteria.AbstractCriteriaBuilder.invokeMethod(AbstractCriteriaBuilder.java:302)

Eric Helgeson • Jan 20 '20

Stackoverflow may be a better place to ask questions - i'm not sure what your question has to do with this post.

Jason Heithoff • Jul 29 '19

Great notes, wanted to add some of mine:

Spring Security CAS will now require this dependency:

compile group: 'org.springframework.security', name: 'spring-security-cas', version: '5.1.5.RELEASE'

An older plugin of mine was using the older hystrix library which isn't supported in spring boot 2 so:

Change:

compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-hystrix', version: '*'

compile group: 'org.springframework.cloud', name: 'spring-cloud-starter-netflix-hystrix', version: '2.1.2.RELEASE'

Tirla-Alin • Mar 4 '20

Great post!

miguel bautista • Oct 8 '19 • Edited

Hello. Is there a way to avoid running Bootstrap again after changing a class? my problem is that I have a lot of initialization processes there. thanks

vijaykanwar • Sep 23 '19

Hi Eric

We need to update grail 2.3.8 to latest 4.
What is the best approach to do that?
is any think you can help me on this ?

Thanks
vijay Kanwar

Eric Helgeson • Sep 25 '19

Hi Vijay - I would start by creating a fresh Grails 4 app and pulling over a few parts of the old app at a time - fixing errors as you go. If you find anything that would be useful here - let me know! Also jump on the Grails Slack channel if you have questions.

purpleraven • Apr 17 '22

Best information about upgrade to Grails 4