Aspire.Hosting.Dapr should allow specifying CLI executable location

[ReubenBond]

To allow consuming the dapr CLI in a GitHub Actions workflow, I believe we should support picking up the CLI from an env var value or allow some other way to specify it. Currently, it only checks some fixed locations. For context, see this comment: dotnet/aspire-samples#108 (comment)

cc @philliphoff

[joperezr]

Once this is fixed, we should remove this workaround too: https://github.com/dotnet/aspire-samples/pull/108/files#diff-4086428da29370d30522a6a1482c189fa0479bd64a457ba72b29f27b14c4d079R10

[davidfowl]

Can we find it on the path as an option? There’s already a way to specify the path in the call to AddDapr

[DamianEdwards]

I'm working around this in the samples CI now by capturing the Dapr CLI path output from the step that installs it and injecting it as an environment variable to the build and test steps. Then the AppHost project has code like this:

// Workaround for https://github.com/dotnet/aspire/issues/2219
if (builder.Configuration.GetValue<string>("DAPR_CLI_PATH") is { } daprCliPath)
{
    builder.Services.Configure<DaprOptions>(options =>
    {
        options.DaprPath = daprCliPath;
    });
}