Take TokenCredential instead of bearer token

[thovoll]

All our SDKs take an endpoint and a credential, which is almost always a TokenCredential define in azure_core, with implementations like DefaultAzureCredential in azure_identity. This is laid out in our guidelines.

I recommend taking a look at what we've done for our other Azure SDKs - any packages starting with "azure*" (as opposed to "microsoft.azure*" or something). I'm not sure about data lake specifically, but for storage in general we already have good examples you should match (type names, method names besides casing, param names, etc. - something we all do across official languages):

For example,

• https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/storage/Azure.Storage.Files.DataLake/src
• https://github.com/Azure/azure-sdk-for-java/tree/main/sdk/storage/azure-storage-file-datalake/src

Specific to authentication, the TokenCredential is responsible for authenticating the user and getting a token. How that is attached to your request is up to you (and we have some helps in azure_core that may help, though not as many built out as with our other languages). In general, you should not roll your own authentication. Some libraries will, in addition, take a connection string. Follow whatever official languages are doing for guidance in those cases, though.

Originally posted by @heaths in #358 (comment)

[cataggar]

@thovoll, can you provide examples where this applies? I thought TokenCredential was being used.

[thovoll]

Yes, for example here: https://github.com/thovoll/azure-sdk-for-rust/blob/cf5bf36f7714979e84ee61f2f29cc7ff1cbb07f0/sdk/storage/src/data_lake/clients/data_lake_client.rs#L20

Currently takes a String, but should take a TokenCredential.

[cataggar]

Support for TokenCredential was added