Add examples and some rewording

content/blog/resource-transforms/index.md

@@ -14,14 +14,151 @@ Pulumi has supported a [Transformations](/docs/concepts/options/transformations)
 
 However, there is one major limitation with the existing Transformations system: it isn't able to transform the children of _packaged_ component resources, such as those in [awsx](/registry/packages/awsx) and [eks](/registry/packages/eks). This limitation is due to the fact that _packaged_ component resources are created in a separate provider process and Transformations only work with resources created in your program's process.
 
-To address this limitation we're introducing a new system called [Transforms](/docs/concepts/options/transforms), which works with all resources, including packaged component resources and their children. The new Transforms system is intended to fully replace the old Transformations system.
+To address this limitation we're introducing a new system called [Transforms](/docs/concepts/options/transforms), which works with all resources, including packaged component resources and their children. The new Transforms system is intended to fully replace the old Transformations system (we plan to deprecate the old system in the future).
 
 <!--more-->
 
-Using the new Transforms system is similar to the old system, for example:
+Here's an example that demonstrates adding tags to all `Subnet` child resources created by the `Vpc` packaged component:
 
-TODO
+{{< chooser language "typescript,python,go,csharp" >}}
 
-Note that there are some behavior differences between the two systems, necessary to make Transforms work across process boundaries. A guide on [Migrating from Transformations to Transforms](/docs/concepts/options/transformations/#migrating-from-transformations-to-transforms) is available to help transition to the new system.
+{{% choosable language typescript %}}
 
-We're excited to address this limitation, allowing you to transform all resources in your program, including packaged components. If you have any questions or feedback, please don't hesitate to reach out to us on [Slack](https://slack.pulumi.com/).
+```typescript
+import * as pulumi from "@pulumi/pulumi";
+import * as awsx from "@pulumi/awsx";
+
+const myTags = { test: "TEST" };
+
+pulumi.runtime.registerResourceTransform(args => {
+    if (args.type === "aws:ec2/subnet:Subnet") {
+        const tags = pulumi.output(args.props.tags || {});
+        args.props.tags = tags.apply(t => ({ ...t, ...myTags }));
+        return { props: args.props, opts: args.opts };
+    }
+    return undefined;
+});
+
+const vpc = new awsx.ec2.Vpc("test");
+```
+
+{{% /choosable %}}
+{{% choosable language python %}}
+
+```python
+import pulumi
+from pulumi_awsx import ec2
+
+my_tags = { "test": "TEST" }
+
+def tag_transform(args):
+    if args.type_ == "aws:ec2/subnet:Subnet":
+        tags = pulumi.Output.from_input(args.props.get("tags", {}))
+        args.props["tags"] = tags.apply(lambda v: {**v, **my_tags})
+        return pulumi.ResourceTransformResult(args.props, args.opts)
+
+pulumi.runtime.register_resource_transform(tag_transform)
+
+my_vpc = ec2.Vpc("my-vpc")
+```
+
+{{% /choosable %}}
+{{% choosable language go %}}
+
+```go
+package main
+
+import (
+	"context"
+
+	"github.com/pulumi/pulumi-awsx/sdk/v2/go/awsx/ec2"
+	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
+)
+
+func main() {
+	pulumi.Run(func(ctx *pulumi.Context) error {
+		myTags := map[string]string{"test": "TEST"}
+
+		err := ctx.RegisterResourceTransform(func(_ context.Context, args *pulumi.ResourceTransformArgs) *pulumi.ResourceTransformResult {
+			if args.Type == "aws:ec2/subnet:Subnet" {
+				tags, ok := args.Props["tags"].(pulumi.StringMapInput)
+				if !ok {
+					tags = pulumi.StringMap{}
+				}
+				args.Props["tags"] = tags.ToStringMapOutput().ApplyT(func(m map[string]string) map[string]string {
+					result := make(map[string]string)
+					for k, v := range m {
+						result[k] = v
+					}
+					for k, v := range myTags {
+						result[k] = v
+					}
+					return result
+				})
+				return &pulumi.ResourceTransformResult{
+					Props: args.Props,
+					Opts:  args.Opts,
+				}
+			}
+			return nil
+		})
+		if err != nil {
+			return err
+		}
+
+		_, err = ec2.NewVpc(ctx, "test", nil)
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+}
+```
+
+{{% /choosable %}}
+{{% choosable language csharp %}}
+
+```csharp
+using Pulumi;
+using Pulumi.Awsx.Ec2;
+using System.Collections.Immutable;
+
+await Deployment.RunAsync<MyStack>();
+
+class MyStack : Stack
+{
+    public MyStack() : base(new StackOptions
+    {
+        ResourceTransforms =
+        {
+            async (args, _) => {
+                var myTags = ImmutableDictionary.Create<string, object>()
+                    .Add("test", "Test");
+
+                if (args.Type == "aws:ec2/subnet:Subnet")
+                {
+                    var tags = args.Args.TryGetValue("tags", out var tagsValue) &&
+                        tagsValue is ImmutableDictionary<string, object> tagsDictionary
+                            ? tagsDictionary
+                            : ImmutableDictionary<string, object>.Empty;
+                    tags = tags.AddRange(myTags);
+                    return new(args.Args.SetItem("tags", tags), args.Options);
+                }
+                return null;
+            },
+        }
+    })
+    {
+        var vpc = new Vpc("test");
+    }
+}
+```
+
+{{% /choosable %}}
+
+{{< /chooser >}}
+
+Using the new Transforms system is similar to the old system, but there are some differences between the two systems. A guide on [Migrating from Transformations to Transforms](/docs/concepts/options/transformations/#migrating-from-transformations-to-transforms) is available to help transition to the new system.
+
+We're excited to make it possible to transform all resources in your program, including those from packaged components. If you have any questions or feedback, please don't hesitate to reach out to us on [Slack](https://slack.pulumi.com/).