Logstash Java filter plugin example "./gradlew gem" error

lakechat · November 30, 2020, 6:09pm

I was following Elasticsearch document (https://www.elastic.co/guide/en/logstash/current/java-filter-plugin.html) to write a Java filter plugin for Logtash. Somehow, I could not even get the provided example work. I stuck at " ./gradlew gem" stage. Here is the error message:

FAILURE: Build failed with an exception.
** Where:*
Build file '/Users/taoli/Documents/java_code/logstash-filter-java_filter_example/build.gradle' line: 102
** What went wrong:*

A problem occurred configuring root project 'logstash-filter-java_filter_example'.
> Could not create task ':gem'.
> No signature of method: org.gradle.api.internal.tasks.DefaultTaskDependency$TaskDependencySet.getAt() is applicable for argument types: (ArrayList) values: [[task ':downloadAndInstallJRuby', task ':removeObsoleteJars', ...]]

Possible solutions: getAt(int), getAt(java.lang.String), getAt(java.lang.String), head(), putAt(java.lang.String, java.lang.Object), wait()

I have plugin project and Logstash project in two different folders, and added gradle.properties file in the plugin project with value

LOGSTASH_CORE_PATH=/Users/taoli/Documents/java_code/logstash_src/logstash-core

I suspect that in build.gradle file, something wrong with this line:

apply from: LOGSTASH_CORE_PATH + "/../rubyUtils.gradle"

Because when I tried with "./gradlew build", it complained that it could not find all Logstash api methods.

paul.devereux · December 1, 2020, 11:12am

Hi,

You need to change line 102 from

dependsOn [downloadAndInstallJRuby, removeObsoleteJars, vendor, generateRubySupportFiles]

to

dependsOn([downloadAndInstallJRuby, removeObsoleteJars, vendor, generateRubySupportFiles])

Regards

lakechat · December 1, 2020, 6:01pm

Hi Paul,

Thanks for the response. It did let me move forward by downloading required libraries. But "compileJava" task still fails. It could not find the Logstash apis. So I guess this statement failed:

apply from: LOGSTASH_CORE_PATH + "/../rubyUtils.gradle"

Any idea what went wrong?

Thanks.

Cnu311 · December 2, 2020, 3:02pm

Hi,
I faced the same issue. I found this file (link provided below) and used in my path.

github.com

elastic/logstash/blob/master/rubyUtils.gradle

/*
 * Licensed to Elasticsearch B.V. under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch B.V. licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

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lakechat · December 3, 2020, 12:21am

Hi,

I am able to compile, build and install gem now. Here are what happened:

In plugin project, modify build.gradle line 102, add '()" as pointed out by Paul
In the same file, for this line
implementation fileTree(dir: LOGSTASH_CORE_PATH, include: "build/libs/logstash-core-?.?.?.jar")

it seems not working, so I just replace it with direct path, like this

implementation files('/Users/test/workspace/logstash/logstash-core/build/libs/logstash-core-7.10.1.jar')

It requires JDK to install gem. Somehow, only JDK 8.0 works for me.

Hope these help.

system · December 31, 2020, 12:19am

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