azfile: Adding readme and changelog (#20714)

* Adding README

* Adding doc.go

* Adding log.go

* Adding changelog

sdk/storage/azfile/CHANGELOG.md

@@ -4,8 +4,4 @@
 
 ### Features Added
 
-### Breaking Changes
-
-### Bugs Fixed
-
-### Other Changes
+* This is the initial preview release of the `azfile` library

sdk/storage/azfile/README.md

@@ -0,0 +1,266 @@
+# Azure File Storage SDK for Go
+
+> Service Version: 2020-10-02
+
+Azure File Shares offers fully managed file shares in the cloud that are accessible via the industry standard 
+[Server Message Block (SMB) protocol](https://docs.microsoft.com/windows/desktop/FileIO/microsoft-smb-protocol-and-cifs-protocol-overview). 
+Azure file shares can be mounted concurrently by cloud or on-premises deployments of Windows, Linux, and macOS. 
+Additionally, Azure file shares can be cached on Windows Servers with Azure File Sync for fast access near where the data is being used.
+
+[Source code][source] | [API reference documentation][docs] | [REST API documentation][rest_docs] | [Product documentation][product_docs]
+
+## Getting started
+
+### Install the package
+
+Install the Azure File Storage SDK for Go with [go get][goget]:
+
+```Powershell
+go get github.com/Azure/azure-sdk-for-go/sdk/storage/azfile
+```
+
+### Prerequisites
+
+A supported [Go][godevdl] version (the Azure SDK supports the two most recent Go releases).
+
+You need an [Azure subscription][azure_sub] and a
+[Storage Account][storage_account_docs] to use this package.
+
+To create a new Storage Account, you can use the [Azure Portal][storage_account_create_portal],
+[Azure PowerShell][storage_account_create_ps], or the [Azure CLI][storage_account_create_cli].
+Here's an example using the Azure CLI:
+
+```Powershell
+az storage account create --name MyStorageAccount --resource-group MyResourceGroup --location westus --sku Standard_LRS
+```
+
+### Authenticate the client
+
+The Azure File Storage SDK for Go allows you to interact with four types of resources: the storage
+account itself, file shares, directories, and files. Interaction with these resources starts with an instance of a
+client. To create a client object, you will need the storage account's file service URL and a
+credential that allows you to access the storage account:
+
+```go
+// create a credential for authenticating using shared key
+cred, err := service.NewSharedKeyCredential("<my-storage-account-name>", "<my-storage-account-key>")
+// TODO: handle err
+
+// create service.Client for the specified storage account that uses the above credential
+client, err := service.NewClientWithSharedKeyCredential("https://<my-storage-account-name>.file.core.windows.net/", cred, nil)
+// TODO: handle err
+```
+
+## Key concepts
+
+Azure file shares can be used to:
+
+- Completely replace or supplement traditional on-premises file servers or NAS devices.
+- "Lift and shift" applications to the cloud that expect a file share to store file application or user data.
+- Simplify new cloud development projects with shared application settings, diagnostic shares, and Dev/Test/Debug tool file shares.
+
+### Goroutine safety
+We guarantee that all client instance methods are goroutine-safe and independent of each other ([guideline](https://azure.github.io/azure-sdk/golang_introduction.html#thread-safety)). This ensures that the recommendation of reusing client instances is always safe, even across goroutines.
+
+### Additional concepts
+<!-- CLIENT COMMON BAR -->
+[Client options](https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azcore/policy#ClientOptions) |
+[Accessing the response](https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azcore/runtime#WithCaptureResponse) |
+[Handling failures](https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azcore#ResponseError) |
+[Logging](https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azcore/log)
+<!-- CLIENT COMMON BAR -->
+
+## Examples
+
+### Create a share and upload a file
+
+```go
+const (
+shareName = "sample-share"
+dirName   = "sample-dir"
+fileName  = "sample-file"
+)
+
+// Get a connection string to our Azure Storage account.  You can
+// obtain your connection string from the Azure Portal (click
+// Access Keys under Settings in the Portal Storage account blade)
+// or using the Azure CLI with:
+//
+//     az storage account show-connection-string --name <account_name> --resource-group <resource_group>
+//
+// And you can provide the connection string to your application
+// using an environment variable.
+connectionString := "<connection_string>"
+
+// Path to the local file to upload
+localFilePath := "<path_to_local_file>"
+
+// Get reference to a share and create it
+shareClient, err := share.NewClientFromConnectionString(connectionString, shareName, nil)
+// TODO: handle error
+_, err = shareClient.Create(context.TODO(), nil)
+// TODO: handle error
+
+// Get reference to a directory and create it
+dirClient := shareClient.NewDirectoryClient(dirName)
+_, err = dirClient.Create(context.TODO(), nil)
+// TODO: handle error
+
+// open the file for reading
+file, err := os.OpenFile(localFilePath, os.O_RDONLY, 0)
+// TODO: handle error
+defer file.Close()
+
+// get the size of file
+fInfo, err := file.Stat()
+// TODO: handle error
+fSize := fInfo.Size()
+
+// create the file
+fClient := dirClient.NewFileClient(fileName)
+_, err = fClient.Create(context.TODO(), fSize, nil)
+// TODO: handle error
+
+// upload the file
+err = fClient.UploadFile(context.TODO(), file, nil)
+// TODO: handle error
+```
+
+### Download a file
+
+```go
+const (
+shareName = "sample-share"
+dirName   = "sample-dir"
+fileName  = "sample-file"
+)
+
+connectionString := "<connection_string>"
+
+// Path to the save the downloaded file
+localFilePath := "<path_to_local_file>"
+
+// Get reference to the share
+shareClient, err := share.NewClientFromConnectionString(connectionString, shareName, nil)
+// TODO: handle error
+
+// Get reference to the directory
+dirClient := shareClient.NewDirectoryClient(dirName)
+
+// Get reference to the file
+fClient := dirClient.NewFileClient(fileName)
+
+// create or open a local file where we can download the Azure File
+file, err := os.Create(localFilePath)
+// TODO: handle error
+defer file.Close()
+
+// Download the file
+_, err = fClient.DownloadFile(context.TODO(), file, nil)
+// TODO: handle error
+```
+
+### Traverse a share
+
+```go
+const shareName = "sample-share"
+
+connectionString := "<connection_string>"
+
+// Get reference to the share
+shareClient, err := share.NewClientFromConnectionString(connectionString, shareName, nil)
+// TODO: handle error
+
+// Track the remaining directories to walk, starting from the root
+var dirs []*directory.Client
+dirs = append(dirs, shareClient.NewRootDirectoryClient())
+for len(dirs) > 0 {
+    dirClient := dirs[0]
+    dirs = dirs[1:]
+
+    // Get all the next directory's files and subdirectories
+    pager := dirClient.NewListFilesAndDirectoriesPager(nil)
+    for pager.More() {
+        resp, err := pager.NextPage(context.TODO())
+        // TODO: handle error
+
+        for _, d := range resp.Segment.Directories {
+            fmt.Println(*d.Name)
+            // Keep walking down directories
+            dirs = append(dirs, dirClient.NewSubdirectoryClient(*d.Name))
+        }
+
+        for _, f := range resp.Segment.Files {
+            fmt.Println(*f.Name)
+        }
+    }
+}
+```
+
+## Troubleshooting
+
+All File service operations will return an
+[*azcore.ResponseError][azcore_response_error] on failure with a
+populated `ErrorCode` field. Many of these errors are recoverable.
+The [fileerror][file_error] package provides the possible Storage error codes
+along with various helper facilities for error handling.
+
+```go
+const (
+	connectionString = "<connection_string>"
+	shareName    = "sample-share"
+)
+
+// create a client with the provided connection string
+client, err := service.NewClientFromConnectionString(connectionString, nil)
+// TODO: handle error
+
+// try to delete the share, avoiding any potential race conditions with an in-progress or completed deletion
+_, err = client.DeleteShare(context.TODO(), shareName, nil)
+
+if fileerror.HasCode(err, fileerror.ShareBeingDeleted, fileerror.ShareNotFound) {
+    // ignore any errors if the share is being deleted or already has been deleted
+} else if err != nil {
+    // TODO: some other error
+}
+```
+
+## Next steps
+
+Get started with our [File samples][samples].  They contain complete examples of the above snippets and more.
+
+## Contributing
+
+See the [Storage CONTRIBUTING.md][storage_contrib] for details on building,
+testing, and contributing to this library.
+
+This project welcomes contributions and suggestions.  Most contributions require
+you to agree to a Contributor License Agreement (CLA) declaring that you have
+the right to, and actually do, grant us the rights to use your contribution. For
+details, visit [cla.microsoft.com][cla].
+
+This project has adopted the [Microsoft Open Source Code of Conduct][coc].
+For more information see the [Code of Conduct FAQ][coc_faq]
+or contact [opencode@microsoft.com][coc_contact] with any
+additional questions or comments.
+
+<!-- LINKS -->
+[source]: https://github.com/Azure/azure-sdk-for-go/tree/main/sdk/storage
+[docs]: https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/storage/azfile
+[rest_docs]: https://docs.microsoft.com/rest/api/storageservices/file-service-rest-api
+[product_docs]: https://docs.microsoft.com/azure/storage/files/storage-files-introduction
+[godevdl]: https://go.dev/dl/
+[goget]: https://pkg.go.dev/cmd/go#hdr-Add_dependencies_to_current_module_and_install_them
+[storage_account_docs]: https://docs.microsoft.com/azure/storage/common/storage-account-overview
+[storage_account_create_ps]: https://docs.microsoft.com/azure/storage/common/storage-quickstart-create-account?tabs=azure-powershell
+[storage_account_create_cli]: https://docs.microsoft.com/azure/storage/common/storage-quickstart-create-account?tabs=azure-cli
+[storage_account_create_portal]: https://docs.microsoft.com/azure/storage/common/storage-quickstart-create-account?tabs=azure-portal
+[azure_sub]: https://azure.microsoft.com/free/
+[azcore_response_error]: https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azcore#ResponseError
+[file_error]: https://github.com/Azure/azure-sdk-for-go/tree/main/sdk/storage
+[samples]: https://github.com/Azure/azure-sdk-for-go/blob/main/sdk/storage
+[storage_contrib]: https://github.com/Azure/azure-sdk-for-go/blob/main/CONTRIBUTING.md
+[cla]: https://cla.microsoft.com
+[coc]: https://opensource.microsoft.com/codeofconduct/
+[coc_faq]: https://opensource.microsoft.com/codeofconduct/faq/
+[coc_contact]: mailto:opencode@microsoft.com

sdk/storage/azfile/directory/client_test.go

@@ -1115,7 +1115,3 @@ func (d *DirectoryRecordedTestsSuite) TestDirectoryCreateNegativeWithoutSAS() {
 	_, err = dirClient.Create(context.Background(), nil)
 	_require.Error(err)
 }
-
-// TODO: add tests for listing files and directories after file client is completed
-
-// TODO: add tests for ListHandles and ForceCloseHandles