Can different codebuild builds provide simillar sha256 hash of artifacts inisde build

Question

I'm creating a pipeline triggered by codecommit repo. in build phase it builds .net 6 lambdas using dotnet build and store them using dotnet lambda package commands. when i try to compare the hash of zip artifacts with the hash of artifacts from previous builds stored on s3 (there is a tag on s3 object containing hash) it outputs me different value of newly builded hash even if i get the same binary files. When i try to do the same on my PC it output the same value for hash of zip artifacts in different attempts

Can i update my build stage to have the same hash for unchanged files in zip?

Deeksha · Answer

1. Ensure that the build process is consistent across different builds:
    Verify that the source code, build configuration, and dependencies are exactly the same for each build.
    Confirm that the build environment (e.g., runtime version, SDK versions) is consistent.

2. Check that the build commands (e.g., dotnet build, dotnet lambda package) are executed in the same way.
     Investigate the build artifact packaging process:
     The SHA-256 hash is calculated based on the contents of the final build artifact (e.g., the ZIP file).

3. Ensure that the packaging process (e.g., dotnet lambda package) is consistent and not introducing any changes to the artifact contents.

4. Consider using a deterministic packaging approach, such as setting the ZipFileTimestamps option to Static when using the dotnet 
    lambda package command. Leverage the sha256sum command to verify the hash: After the build, use the sha256sum command to 
   calculate the hash of the local build artifact.

5. Compare this hash with the hash stored in the S3 object tag.
     If the hashes match, the artifact contents are the same, and the issue may be with the way the hash is being calculated or compared.

6. Check the AWS CodeBuild documentation for any updates or changes related to artifact hashing:
     The AWS CodeBuild documentation provides information about the sha256sum parameter for build artifacts.
      Review the documentation for any updates or changes that may affect the way hashes are calculated or compared.

7. Consider using a more robust file integrity verification mechanism:
    In addition to the SHA-256 hash, you could also use other file integrity verification techniques, such as digital signatures or 
    checksums. This can provide an additional layer of assurance that the build artifacts have not been tampered with.

Can different codebuild builds provide simillar sha256 hash of artifacts inisde build

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