Update go-pgx to add connection pool with token refresh. (#145)

* Initial start to integrate sdk
* Updated example to add pgxpool and token refresh logic and tests.
* Update to add verbose output to test in github actions
* Clean up code remove unnecessary comments.
* Update crypto version to latest.
* Update example and README.md

Author: imforster

.github/workflows/go-pgx-integ-tests.yml

@@ -52,4 +52,4 @@ jobs:
         REGION: ${{ secrets.GO_PGX_CLUSTER_REGION }}
       run: |
         go env -w GOPROXY=direct
-        go test
+        go test -v

go/pgx/README.md

@@ -1,29 +1,83 @@
-# Aurora DSQL pgx code examples
+# PGX with Aurora DSQL
 
 ## Overview
 
-The code examples in this topic show you how to use DSQL with Go pgx.
+This code example demonstrates how to use the `pgx` driver with Amazon Aurora DSQL. The example shows you how to connect to an Aurora DSQL cluster and perform database operations using IAM authentication.
+
+Aurora DSQL is a distributed SQL database service that provides high availability and scalability for your PostgreSQL-compatible applications. `pgx` is a pure Go driver and toolkit for PostgreSQL that offers robust features including automatic connection pool management and authentication token refresh.
+
+
+## About the code example
+
+The example demonstrates a flexible connection approach using IAM authentication:
+
+- Implements automatic token refresh mechanism to maintain continuous database connectivity
+- Handles secure IAM-based authentication token generation
+- Provides connection pooling and management
+- Demonstrates best practices for Aurora DSQL connectivity in Go applications
+
+## ⚠️ Important
+
+- Running this code might result in charges to your AWS account.
+- We recommend that you grant your code least privilege. At most, grant only the
+  minimum permissions required to perform the task. For more information, see
+  Grant least privilege in the AWS IAM User Guide.
+- This code is not tested in every AWS Region. For more information, see
+  AWS Regional Services.
+
+## Configuration
+
+The following environment variables can be used to configure the connection parameter in this example:
+
+- `CLUSTER_ENDPOINT`: Your Aurora cluster endpoint (required)
+- `REGION`: AWS region where your cluster is located (required)
+- `CLUSTER_USER`: Database user (defaults to "admin")
+- `DB_HOST`: Database host (defaults to CLUSTER_ENDPOINT)
+- `DB_PORT`: Database port (defaults to 5432)
+- `DB_USER`: Database user (defaults to CLUSTER_USER)
+- `DB_NAME`: Database name (defaults to "postgres")
+- `DB_USE_IAM`: Whether to use IAM authentication (defaults to false)
+- `DB_REFRESH_TOKEN`: Whether to enable token refresh (defaults to true)
+- `TOKEN_REFRESH_INTERVAL`: Token refresh interval in seconds (defaults to 900 seconds / 15 minutes)
 
 ## Run the examples
 
 ### Prerequisites
 
-* Go version >= 1.21
-* AWS credentials file is configured
-
+- You must have an AWS account, and have your default credentials and AWS Region
+  configured as described in the
+  [Globally configuring AWS SDKs and tools](https://docs.aws.amazon.com/credref/latest/refdocs/creds-config-files.html)
+  guide.
+-You must have an Aurora DSQL cluster. For information about creating an Aurora DSQL cluster, see the
+      [Getting started with Aurora DSQL](https://docs.aws.amazon.com/aurora-dsql/latest/userguide/getting-started.html)
+      guide.
+- If connecting as a non-admin user, ensure the user is linked to an IAM role and is granted access to the `myschema`
+  schema. See the
+  [Using database roles with IAM roles](https://docs.aws.amazon.com/aurora-dsql/latest/userguide/using-database-and-iam-roles.html)
+  guide.
+- Go version >= 1.21
 
 ### Setup test running environment
 
 Ensure you are authenticated with AWS credentials. No other setup is needed besides having Go installed.
 
+### Environment Variables
+Set the following required environment variables:
+
+```shell
+# Your cluster endpoint (e.g., "cluster-name.cluster-xxx.region.rds.amazonaws.com")
+export CLUSTER_ENDPOINT="<your cluster endpoint>"
+
+# Your AWS region (e.g., "us-east-1")
+export REGION="<your cluster region>"
+```
+
 ### Run the example tests
 
 In a terminal run the following commands:
 
 ```sh
 # Use the account credentials dedicated for golang
-export CLUSTER_ENDPOINT="<your cluster endpoint>"
-export REGION="<your cluster region>"
 go env -w GOPROXY=direct
 go test
 
@@ -32,6 +86,22 @@ go build
 ./example
 ```
 
+## Token Refresh
+
+Token Refresh
+The implementation includes an automatic token refresh mechanism that:
+
+1. Creates a new token before the current one expires (default: every 15 minutes)
+
+1. Ensures continuous database connectivity
+
+1. Handles token generation and rotation securelye fresh connections with valid authentication tokens.
+
+## Additional resources
+
+- [Amazon Aurora DSQL Documentation](https://docs.aws.amazon.com/aurora-dsql/latest/userguide/what-is-aurora-dsql.html)
+- [AWS SDK for Go Documentation](https://docs.aws.amazon.com/sdk-for-go/)
+
 ---
 
 Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.