Fix number format in Rule Builder

[patrickmann]

Resolves #23541

Description

• Fix pipeline rule builder "mismatched input" parse error when numeric condition values exceed 999
• Root cause: Freemarker's default locale-aware number formatting inserts thousand separators (e.g., 1,000) into generated rule source code, which the ANTLR parser rejects
• Set numberFormat("computer") on the rule builder's Freemarker configurations to produce separator-free numbers
• Also fixes the cosmetic display of numbers in condition titles

Details

The SecureFreemarkerConfigProvider is a Guice Provider that acts as a factory — each call to get() returns a new Configuration instance. This is a deliberate design choice: different consumers (rule builder, email templates, etc.) can customize their instance without affecting others. That's why the fix is safe — setting numberFormat("computer") on the rule builder's instance doesn't change how email templates format numbers.

The two separate Configurations matter: RuleBuilderRegistry owns the config for generating rule source code (fragment templates like to_long($message.${field}) <= ${fieldValue}). RuleBuilderService owns a separate config for generating display titles (like Field 'bytes' greater than or equal '10000'). Both needed the fix independently because they create their own Configuration instances from SecureFreemarkerConfigProvider.get().

Test

• Added ParserUtilTest verifying fragment generation with numbers > 999 produces no thousand separators
• Added RuleBuilderServiceTest verifying title generation with numbers > 999 produces no thousand separators
• All existing tests pass

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (non-breaking change)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have requested a documentation update.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[Copilot]

Pull request overview

Fixes Pipeline Rule Builder failures when numeric condition values exceed 999 by preventing Freemarker locale-specific thousand separators from being inserted into generated rule source and condition/action titles.

Changes:

• Configure Rule Builder Freemarker Configuration instances to use numberFormat("computer") (no thousand separators).
• Add regression tests ensuring generated fragments and titles for values > 999 contain no separators.
• Add an unreleased changelog entry for the fix.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
graylog2-server/src/main/java/org/graylog/plugins/pipelineprocessor/rulebuilder/parser/RuleBuilderService.java	Sets Freemarker number format to computer for title template rendering.
graylog2-server/src/main/java/org/graylog/plugins/pipelineprocessor/rulebuilder/RuleBuilderRegistry.java	Sets Freemarker number format to computer for fragment template rendering used in rule source generation.
graylog2-server/src/test/java/org/graylog/plugins/pipelineprocessor/rulebuilder/parser/ParserUtilTest.java	Adds config + test asserting fragment rendering doesn’t introduce thousand separators for large numbers.
graylog2-server/src/test/java/org/graylog/plugins/pipelineprocessor/rulebuilder/parser/RuleBuilderServiceTest.java	Adds test asserting title rendering doesn’t introduce thousand separators for large numbers.
changelog/unreleased/issue-23541.toml	Adds release note entry for issue #23541.

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