Bicep should not require an intermediate temp folder

[JustinGrote]

Per #14403, a temp folder is used to copy all bicep files during a deployment (which currently only copies the main file).

I'd like to understand why this is necessary, it's not like the files are locked or anything, and the bicep compiler works just fine accepting a direct bicep file and then finding the relative other bicep files as modules.

It should instead just work with the files in-place.

Specifically here:

azure-powershell/src/Resources/ResourceManager/Utilities/BicepUtility.cs

Line 58 in 16e4c12

string tempPath = Path.Combine(Path.GetTempPath(), Path.GetFileName(bicepTemplateFilePath));

Since you are just calling bicep build anyways, you should instead of saving it to a file use the --stdout parameter and capture the output.

Alternatively if you want a json file and can't handle accepting the stream, you can use --outdir and specify a GUID-randomized destination path in temp (to avoid issues with parallel deployments)

However, honestly you should just be incorporating and using the Bicep .NET APIs rather than the CLI command. See https://github.com/StefanIvemo/BicepPowerShell/blob/main/Source/Private/ParseBicep.ps1 for an implementation example (in powershell but easy to convert to C#)

Bicep CLI version 0.3.1 (d0f5c9b164)

Usage:
  bicep build [options] <file>
    Builds a .bicep file

    Arguments:
      <file>        The input file.

    Options:
      --outdir <dir>    Saves the output at the specified directory.
      --outfile <file>  Saves the output as the specified file path.
      --stdout          Prints the output to stdout.

    Examples:
      bicep build file.bicep
      bicep build file.bicep --stdout
      bicep build file.bicep --outdir dir1
      bicep build file.bicep --outfile file.json

  bicep decompile [options] <file>
    Attempts to decompile a template .json file to .bicep

    Arguments:
      <file>        The input file.

  bicep [options]
    Options:
      --version  -v   Shows bicep version information
      --help     -h   Shows this usage information

[BethanyZhou]

Hi JustinGrote,

Thank you for your insights, it helps me a lot.

The reasons why a temp folder is used to copy all bicep files during a deployment are as following:

1. We want to hide bicep build result from user because we think the compile process should be transparent to user who targets to deployment.
2. Using 'stdout' is a good idea to avoid temporary json file. Given that we need read json file twice during our deployment process: first for dynamic parameter processing; second for template deployment, we decided to keep json file in a temporary folder.
3. When we supported bicep deployment feature, the latest bicep CLI version is v0.2.*. At that moment, bicep had not supported '--outdir' yet. Json file will be placed into the location same with main bicep file. To avoid overwriting important file in mistake, we decided to copy bicep file to a temporary folder.
4. Besides, we planned to support TemplateUri in accepting bicep file at the initial design. In this case, we need download the bicep file from its uri. These downloaded files should be put into a temporary folder as well. However, we removed this feature for some feasibility factors .
5. Combining point 3 and 4, we keeped all bicep files in the temp folder.

Reviewed our current situation, I agree with you it is unnecessary to copy all bicep files to a temp folder. Redirect the output path by --outdir is a good idea.

And we will evaluate the pros and cons about using the Bicep .NET APIs.

Thanks again,
Beth

[JustinGrote]

This was resolved with #14444. Thank you @BethanyZhou!