Bug: Processor Condition Doesn't Allow Dict Access To .Metadata

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Introduction

In this article, we will be discussing a bug that occurs when trying to access a dictionary within the .Metadata field in a processor condition. This bug is specific to the Conduit processor and has been identified in version v0.13.4. We will go through the steps to reproduce the bug, the version in which it was identified, and provide a solution to resolve the issue.

Bug Description

The bug occurs when the processor crashes with an error message indicating that the condition is invalid due to a bad character in the template. The error message is as follows:

failed to build source processor tasks: invalid condition: template: :1: bad character U+005B '['" stack=[{"file":"github.com/conduitio/conduit@v0.13.4/pkg/provisioning/service.go","func":"github.com/conduitio/conduit/pkg/provisioning.(*Service).Init","line":132},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/provisioning/service.go","func":"github.com/conduitio/conduit/pkg/provisioning.(*Service).provisionPipeline","line":260},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/lifecycle-poc/service.go","func":"github.com/conduitio/conduit/pkg/lifecycle-poc.(*Service).Start","line":159},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/lifecycle-poc/service.go","func":"github.com/conduitio/conduit/pkg/lifecycle-poc.(*Service).buildRunnablePipeline","line":301},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/lifecycle-poc/service.go","func":"github.com/conduitio/conduit/pkg/lifecycle-poc.(*Service).buildSourceTasks","line":411},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/processor/service.go","func":"github.com/conduitio/conduit/pkg/processor.(*Service).MakeRunnableProcessor","line":105}]

Steps to Reproduce

To reproduce the bug, follow these steps:

  1. Create a processor with a condition that accesses a dictionary within the .Metadata field. For example:
- id: route_default
  plugin: 'filter'
  condition: '{{ ne .Metadata["outbox.route"] "default" }}'
  1. Run the processor with the condition specified above.

Version

The bug was identified in version v0.13.4 of the Conduit processor.

Solution

To resolve the bug, you can modify the condition to access the dictionary within the .Metadata field using the get function. For example:

- id: route_default
  plugin: 'filter'
  condition: '{{ get .Metadata "outbox.route" }} != "default" '

Alternatively, you can use the eq function to compare the value of the dictionary with the expected value. For example:

- id: route_default
  plugin: 'filter'
  condition: '{{ eq .Metadata["outbox.route"] "default" }}'

By modifying the condition to use the get or eq function, can resolve the bug and access the dictionary within the .Metadata field without encountering the invalid condition error.

Conclusion

Introduction

In our previous article, we discussed a bug that occurs when trying to access a dictionary within the .Metadata field in a processor condition. This bug is specific to the Conduit processor and has been identified in version v0.13.4. In this article, we will provide a Q&A section to help you better understand the bug and its resolution.

Q&A

Q: What is the bug in the Conduit processor?

A: The bug occurs when trying to access a dictionary within the .Metadata field in a processor condition. This results in an invalid condition error and causes the processor to crash.

Q: What is the error message that I will see when the bug occurs?

A: The error message will be as follows:

failed to build source processor tasks: invalid condition: template: :1: bad character U+005B '['" stack=[{"file":"github.com/conduitio/conduit@v0.13.4/pkg/provisioning/service.go","func":"github.com/conduitio/conduit/pkg/provisioning.(*Service).Init","line":132},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/provisioning/service.go","func":"github.com/conduitio/conduit/pkg/provisioning.(*Service).provisionPipeline","line":260},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/lifecycle-poc/service.go","func":"github.com/conduitio/conduit/pkg/lifecycle-poc.(*Service).Start","line":159},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/lifecycle-poc/service.go","func":"github.com/conduitio/conduit/pkg/lifecycle-poc.(*Service).buildRunnablePipeline","line":301},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/lifecycle-poc/service.go","func":"github.com/conduitio/conduit/pkg/lifecycle-poc.(*Service).buildSourceTasks","line":411},{"file":"github.com/conduitio/conduit@v0.13.4/pkg/processor/service.go","func":"github.com/conduitio/conduit/pkg/processor.(*Service).MakeRunnableProcessor","line":105}]

Q: How can I reproduce the bug?

A: To reproduce the bug, follow these steps:

  1. Create a processor with a condition that accesses a dictionary within the .Metadata field. For example:
- id: route_default
  plugin: 'filter'
  condition: '{{ ne .Metadata["outbox.route"] "default" }}'
  1. Run the processor with the condition specified above.

Q: What is the solution to the bug?

A: To resolve the bug, you can modify the condition to access the dictionary within the .Metadata field using the get function. For example:

- id: route_default
  plugin: 'filter'
  condition: '{{ get .Metadata "outbox.route" }} != "default" '

Alternatively, you can use the eq function to compare the value of the dictionary with the expected value. For example:

- id: route_default
  plugin: 'filter'
  condition: '{{ eq .Metadata["outbox.route"] "default" }}'

Q: Why do I need to use the get or eq function to access the dictionary?

A: The get or eq function is used to access the dictionary within the .Metadata field because the original condition syntax is not supported in the Conduit processor. By using the get or eq function, you can safely access the dictionary without encountering the invalid condition error.

Q: Is this bug specific to the Conduit processor?

A: Yes, this bug is specific to the Conduit processor and has been identified in version v0.13.4.

Q: How can I prevent this bug from occurring in the future?

A: To prevent this bug from occurring in the future, make sure to use the get or eq function to access the dictionary within the .Metadata field. Additionally, always check the Conduit processor documentation for any updates or changes to the condition syntax.

Conclusion

In conclusion, the bug that occurs when trying to access a dictionary within the .Metadata field in a processor condition is a known issue in version v0.13.4 of the Conduit processor. By modifying the condition to use the get or eq function, you can resolve the bug and access the dictionary without encountering the invalid condition error. We hope this Q&A article has provided valuable information to help you resolve this issue and continue using the Conduit processor with confidence.