Parameters¶

Read and cache configuration from SSM Parameter Store, Secrets Manager, DynamoDB or AppConfig.

Install¶

Use Go 1.27 or newer:

CGO_ENABLED=0 go get github.com/rambow-cloud/powertools-lambda-go/parameters@v1.2.0
CGO_ENABLED=0 go get github.com/rambow-cloud/powertools-lambda-go/logger@v1.2.0

Read an SSM parameter¶

Create a String parameter named /orders/feature with value enabled. This example calls SSM: configure the AWS SDK region and credentials, and allow ssm:GetParameter for that parameter.

Input

/orders/feature = enabled

Code

package main

import (
    "context"
    "os"

    "github.com/rambow-cloud/powertools-lambda-go/logger"
    "github.com/rambow-cloud/powertools-lambda-go/parameters/ssm"
)

func main() {
    appLog := logger.New(logger.WithServiceName("orders"))
    if err := run(appLog); err != nil {
        if logErr := appLog.Error("Application failed", err); logErr != nil {
            panic(logErr)
        }
        os.Exit(1)
    }
}

func run(appLog *logger.Logger) error {
    value, err := ssm.GetParameter(context.Background(), "/orders/feature", ssm.GetOptions{})
    if err != nil {
        return err
    }
    return appLog.Info("Feature configuration loaded", logger.Fields{"feature": value})
}

The Logger timestamp varies on each run.

Output

{
  "level": "INFO",
  "message": "Feature configuration loaded",
  "timestamp": "2026-10-15T00:00:00.000Z",
  "service": "orders",
  "sampling_rate": 0,
  "feature": "enabled"
}

Cache a value for longer¶

value, err := ssm.GetParameter(ctx, "/orders/feature", ssm.GetOptions{
    Options: parameters.Options{MaxAge: parameters.Age(30 * time.Second)},
})

Repeated calls within the cache lifetime reuse the value. Set ForceFetch: true to bypass a cached value for that call. The default lifetime is five seconds.

Decode JSON configuration¶

If /orders/config contains {"enabled":true,"limit":10}, request a JSON transform:

value, err := ssm.GetParameter(ctx, "/orders/config", ssm.GetOptions{
    Options: parameters.Options{Transform: parameters.JSON},
})

The returned value is a decoded object with enabled and limit, rather than a JSON string. Import the root parameters package for transform constants.

Choose a provider¶

Use New(client, ...) when you need a custom SDK client, region or endpoint. See provider options for examples.

Things to know¶

• Use the invocation context for service calls; default providers and their caches are reused across warm invocations.
• Reading SecureString parameters also requires decryption permissions. Grant only access to the configuration your function needs.
• Cache entries are local to an execution environment. Use ClearCaches or a provider’s ClearCache when explicitly invalidating them.

Next steps¶

See the API and behavior notes for advanced options, and module installation for dependencies.