How to Merge 2 Lists Together (Of Containers) In Helm?

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To merge two lists together in Helm, you can use the append function. This function concatenates two or more lists, resulting in a single list that contains all the elements of the original lists.


For example, if you have two lists named list1 and list2, you can merge them together like this:

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{{ $mergedList := append list1 list2 }}


This will combine the elements of list1 and list2 into a single list called mergedList. You can then use this merged list in your Helm templates as needed.

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How to debug errors when merging lists in Helm?

When merging lists in Helm, there are a few common errors that can occur. These include issues such as incorrect syntax in the values file, conflicting values between lists, or mismatched data types. Here are some tips for debugging these errors:

  1. Check the syntax of your values file: Ensure that the syntax in your values file is correct and that there are no typos or missing commas. Check for any nested lists or maps that may be causing issues.
  2. Verify that the lists you are trying to merge have compatible data types: Lists with incompatible data types (e.g. string and integer) cannot be merged. Make sure that the values in the lists you are trying to merge are of the same data type.
  3. Use the {{ printf "%#v" .Values.someList }} template to debug the values of your lists: This will allow you to see the contents of the lists in your template and identify any issues with the data.
  4. Use the toYaml function to convert your lists to YAML format: This can help you to see the structure of your lists more clearly and identify any discrepancies or conflicts that may be causing errors.
  5. Break down the merge operation into smaller steps: If you are still having trouble merging lists, try breaking down the merge operation into smaller steps and merging the lists incrementally. This can help you to pinpoint the source of the error more easily.


By following these tips and carefully reviewing your values files and template code, you should be able to debug errors when merging lists in Helm more effectively.


How to merge large lists efficiently in Helm?

Merging large lists in Helm efficiently can be challenging due to the limitations of the templating language. However, there are a few strategies that can help improve performance:

  1. Use the append function: Helm provides the append function, which can be used to merge two or more lists together efficiently. By using this function instead of manually merging the lists, you can avoid unnecessary iterations and improve performance.
  2. Split the lists into smaller chunks: If you have very large lists that need to be merged, consider splitting them into smaller chunks and merging each chunk separately. This can help reduce the overall computational complexity and improve the performance of the merge operation.
  3. Use external tools or scripts: If Helm's templating language is too limited for your use case, consider using external tools or scripts to perform the merge operation instead. You can write a custom script in a language like Python or JavaScript to handle the merging of large lists more efficiently.
  4. Optimize your template logic: Review your Helm templates and look for opportunities to optimize the logic that processes the lists. Avoid unnecessary loops or iterations, and try to simplify the template logic as much as possible to improve performance.


By using these strategies and optimizing your Helm templates, you can merge large lists more efficiently and improve the overall performance of your Helm deployments.


How to merge lists with encryption or hashing in Helm?

To merge lists with encryption or hashing in Helm, you can use built-in functions such as sha256 or sops. Here's a step-by-step guide:

  1. Import the necessary functions:
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{{- include "helm-toolkit.imports" . }}


  1. Use the sha256 function to hash the contents of your lists. For example, if you have two lists list1 and list2, you can concatenate them and then hash the result:
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{{$mergedLists := list}}
{{$mergedLists = append $mergedLists list1}}
{{$mergedLists = append $mergedLists list2}}
{{$hash := sha256 (printf "%s" $mergedLists)}}


  1. Alternatively, you can use a tool like sops to encrypt or decrypt your lists before merging them. First, install sops and follow the instructions to encrypt your lists. Then, in your Helm templates, you can decrypt the lists using sops and merge them:
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{{$decryptedList1 := sops_decrypt (required $list1)}}
{{$decryptedList2 := sops_decrypt (required $list2)}}
{{$mergedLists := list}}
{{$mergedLists = append $mergedLists $decryptedList1}}
{{$mergedLists = append $mergedLists $decryptedList2}}


By using these methods, you can securely merge lists with encryption or hashing in Helm. Remember to follow best practices for handling sensitive data and encryption keys.

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