Add support for shallow cloning azcore.Client instances (Azure#21065)

* Add support for shallow cloning azcore.Client instances

This allows for multiple clients to share the same underlying pipeline
while having the correct client name string in traces.

* improved field names

sdk/azcore/CHANGELOG.md

@@ -1,11 +1,54 @@
 # Release History
 
+## 1.7.0 (Unreleased)
+
+### Features Added
+* Added method `WithClientName()` to type `azcore.Client` to support shallow cloning of a client with a new name used for tracing.
+
+### Breaking Changes
+> These changes affect only code written against beta versions v1.7.0-beta.1 or v1.7.0-beta.2
+* The beta features for CAE, tracing, and fakes have been omitted for this release.
+
+### Bugs Fixed
+
+### Other Changes
+
+## 1.7.0-beta.2 (2023-06-06)
+
+### Breaking Changes
+> These changes affect only code written against beta version v1.7.0-beta.1
+* Method `SpanFromContext()` on type `tracing.Tracer` had the `bool` return value removed.
+  * This includes the field `SpanFromContext` in supporting type `tracing.TracerOptions`.
+* Method `AddError()` has been removed from type `tracing.Span`.
+* Method `Span.End()` now requires an argument of type `*tracing.SpanEndOptions`.
+
 ## 1.6.1 (2023-06-06)
 
+### Bugs Fixed
+* Fixed an issue in `azcore.NewClient()` and `arm.NewClient()` that could cause an incorrect module name to be used in telemetry.
+
+### Other Changes
+* This version contains all bug fixes from `v1.7.0-beta.1`
+
+## 1.7.0-beta.1 (2023-05-24)
+
+### Features Added
+* Restored CAE support for ARM clients.
+* Added supporting features to enable distributed tracing.
+  * Added func `runtime.StartSpan()` for use by SDKs to start spans.
+  * Added method `WithContext()` to `runtime.Request` to support shallow cloning with a new context.
+  * Added field `TracingNamespace` to `runtime.PipelineOptions`.
+  * Added field `Tracer` to `runtime.NewPollerOptions` and `runtime.NewPollerFromResumeTokenOptions` types.
+  * Added field `SpanFromContext` to `tracing.TracerOptions`.
+  * Added methods `Enabled()`, `SetAttributes()`, and `SpanFromContext()` to `tracing.Tracer`.
+  * Added supporting pipeline policies to include HTTP spans when creating clients.
+* Added package `fake` to support generated fakes packages in SDKs.
+  * The package contains public surface area exposed by fake servers and supporting APIs intended only for use by the fake server implementations.
+  * Added an internal fake poller implementation.
+
 ### Bugs Fixed
 * Retry policy always clones the underlying `*http.Request` before invoking the next policy.
 * Added some non-standard error codes to the list of error codes for unregistered resource providers.
-* Fixed an issue in `azcore.NewClient()` and `arm.NewClient()` that could cause an incorrect module name to be used in telemetry.
 
 ## 1.6.0 (2023-05-04)
 

sdk/azcore/core.go

@@ -73,6 +73,10 @@ type ClientOptions = policy.ClientOptions
 type Client struct {
 	pl runtime.Pipeline
 	tr tracing.Tracer
+
+	// cached on the client to support shallow copying with new values
+	tp     tracing.Provider
+	modVer string
 }
 
 // NewClient creates a new Client instance with the provided values.
@@ -100,7 +104,13 @@ func NewClient(clientName, moduleVersion string, plOpts runtime.PipelineOptions,
 	pl := runtime.NewPipeline(mod, moduleVersion, plOpts, options)
 
 	tr := options.TracingProvider.NewTracer(client, moduleVersion)
-	return &Client{pl: pl, tr: tr}, nil
+
+	return &Client{
+		pl:     pl,
+		tr:     tr,
+		tp:     options.TracingProvider,
+		modVer: moduleVersion,
+	}, nil
 }
 
 // Pipeline returns the pipeline for this client.
@@ -112,3 +122,11 @@ func (c *Client) Pipeline() runtime.Pipeline {
 func (c *Client) Tracer() tracing.Tracer {
 	return c.tr
 }
+
+// WithClientName returns a shallow copy of the Client with its tracing client name changed to clientName.
+// Note that the values for module name and version will be preserved from the source Client.
+//   - clientName - the fully qualified name of the client ("package.Client"); this is used by the tracing provider when creating spans
+func (c *Client) WithClientName(clientName string) *Client {
+	tr := c.tp.NewTracer(clientName, c.modVer)
+	return &Client{pl: c.pl, tr: tr, tp: c.tp, modVer: c.modVer}
+}

sdk/azcore/core_test.go

@@ -7,11 +7,16 @@
 package azcore
 
 import (
+	"context"
+	"net/http"
 	"reflect"
 	"testing"
 
+	"github.com/Azure/azure-sdk-for-go/sdk/azcore/internal/exported"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/runtime"
+	"github.com/Azure/azure-sdk-for-go/sdk/azcore/tracing"
+	"github.com/Azure/azure-sdk-for-go/sdk/internal/mock"
 	"github.com/stretchr/testify/require"
 )
 
@@ -131,3 +136,41 @@ func TestNewClientError(t *testing.T) {
 	require.Error(t, err)
 	require.Nil(t, client)
 }
+
+func TestClientWithClientName(t *testing.T) {
+	srv, close := mock.NewServer()
+	defer close()
+
+	var clientName string
+	var modVersion string
+	client, err := NewClient("module/package.Client", "v1.0.0", runtime.PipelineOptions{}, &policy.ClientOptions{
+		TracingProvider: tracing.NewProvider(func(name, version string) tracing.Tracer {
+			clientName = name
+			modVersion = version
+			return tracing.NewTracer(func(ctx context.Context, spanName string, options *tracing.SpanOptions) (context.Context, tracing.Span) {
+				return ctx, tracing.Span{}
+			}, nil)
+		}, nil),
+		Transport: srv,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, client)
+	require.NotZero(t, client.Pipeline())
+	require.NotZero(t, client.Tracer())
+	require.EqualValues(t, "package.Client", clientName)
+	require.EqualValues(t, "v1.0.0", modVersion)
+
+	const requestEndpoint = "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/fakeResourceGroupo/providers/Microsoft.Storage/storageAccounts/fakeAccountName"
+	req, err := exported.NewRequest(context.Background(), http.MethodGet, srv.URL()+requestEndpoint)
+	require.NoError(t, err)
+	srv.SetResponse()
+	_, err = client.Pipeline().Do(req)
+	require.NoError(t, err)
+
+	newClient := client.WithClientName("other.Client")
+	require.EqualValues(t, "other.Client", clientName)
+	require.EqualValues(t, "v1.0.0", modVersion)
+	require.EqualValues(t, client.Pipeline(), newClient.Pipeline())
+	_, err = newClient.Pipeline().Do(req)
+	require.NoError(t, err)
+}