Developing applications with Momento SDKs

Welcome! This page provides information about common constructs you will need in order to assemble Momento clients in all of our SDKs. This page covers how to provide your Momento credentials (called auth tokens), how to configure your client, and some basic information about error handling and production readiness.

Constructing a Topics client

The TopicClient is the main object you will use in your code to interact with Momento services. To instantiate one, you need to pass a CredentialProvider, a Configuration, and a default time to live (TTL) value. The default TTL determines how long items using that CacheClient will be stored in the cache before the cache deletes them.

Here is an example of how to construct a TopicClient:

JavaScript

new TopicClient({
  configuration: TopicConfigurations.Default.latest(),
  credentialProvider: CredentialProvider.fromEnvironmentVariable('MOMENTO_API_KEY'),
});

info

Full example code and imports can be found here

Python

TopicClientAsync(
    TopicConfigurations.Default.latest(), CredentialProvider.from_environment_variable("MOMENTO_API_KEY")
)

info

Full example code and imports can be found here

Kotlin

TopicClient(
    CredentialProvider.fromEnvVar("MOMENTO_API_KEY"), TopicConfigurations.Laptop.latest
).use { topicClient ->
    //...
}

info

Full example code and imports can be found here

Go

credProvider, err := auth.NewEnvMomentoTokenProvider("MOMENTO_API_KEY")
if err != nil {
	panic(err)
}

topicClient, err = momento.NewTopicClient(
	config.TopicsDefault(),
	credProvider,
)
if err != nil {
	panic(err)
}

info

Full example code and imports can be found here

C#

new TopicClient(
    TopicConfigurations.Laptop.latest(),
    new EnvMomentoTokenProvider("MOMENTO_API_KEY")
);

info

Full example code and imports can be found here

Rust

  let _topic_client = TopicClient::builder()
      .configuration(momento::topics::configurations::Laptop::latest())
      .credential_provider(CredentialProvider::from_env_var("MOMENTO_API_KEY")?)
      .build()?;

info

Full example code and imports can be found here

Swift

do {
    let credentialProvider = try CredentialProvider.fromEnvironmentVariable(envVariableName: "MOMENTO_API_KEY")
    let topicClient = TopicClient(
        configuration: TopicClientConfigurations.iOS.latest(),
        credentialProvider: credentialProvider
    )
} catch {
    print("Unable to create topic client: \(error)")
    exit(1)
}

info

Full example code and imports can be found here

Dart

try {
  final topicClient = TopicClient(
      CredentialProvider.fromEnvironmentVariable("MOMENTO_API_KEY"),
      TopicClientConfigurations.latest());
} catch (e) {
  print("Unable to create topic client: $e");
  exit(1);
}

info

Full example code and imports can be found here

Instantiating credential providers using Momento API keys

You need to provide a Momento API key when instantiating a Momento client. If you don't have one yet, you can get one from the Momento Web Console. Once you have a token, provide it to Momento SDKs when you create an instance of CredentialProvider. There are convenient factory methods provided to construct a CredentialProvider object, either from an environment variable or from a String. Below is an example of how to instantiate CredentialProvider from an environment variable:

JavaScript

CredentialProvider.fromEnvironmentVariable('MOMENTO_API_KEY');

info

Full example code and imports can be found here

Python

CredentialProvider.from_environment_variable("MOMENTO_API_KEY")

info

Full example code and imports can be found here

Java

CredentialProvider.fromEnvVar("MOMENTO_API_KEY");

info

Full example code and imports can be found here

Kotlin

CredentialProvider.fromEnvVar("MOMENTO_API_KEY")

info

Full example code and imports can be found here

Go

credentialProvider, err = auth.NewEnvMomentoTokenProvider("MOMENTO_API_KEY")
if err != nil {
	panic(err)
}

info

Full example code and imports can be found here

PHP

CredentialProvider::fromEnvironmentVariable("MOMENTO_API_KEY");

info

Full example code and imports can be found here

Rust

  let _credential_provider = CredentialProvider::from_env_var("MOMENTO_API_KEY".to_string());


allow(non_snake_case)]
b fn example_API_ConfigurationLaptop() {
  let _config = momento::cache::configurations::Laptop::latest();


allow(non_snake_case)]
b fn example_API_ConfigurationInRegionDefaultLatest() {
  let _config = momento::cache::configurations::InRegion::latest();


allow(non_snake_case)]
b fn example_API_ConfigurationInRegionLowLatency() {
  let _config = momento::cache::configurations::LowLatency::latest();


allow(non_snake_case)]
b fn example_API_ConfigurationLambdaLatest() {
  let _config = momento::cache::configurations::Lambda::latest();


allow(non_snake_case)]
b fn example_API_InstantiateCacheClient() -> Result<(), MomentoError> {
  let _cache_client = CacheClient::builder()
      .default_ttl(Duration::from_secs(60))
      .configuration(Laptop::latest())
      .credential_provider(CredentialProvider::from_env_var(
          "MOMENTO_API_KEY".to_string(),
      )?)
      .build()?;

info

Full example code and imports can be found here

Elixir

Momento.Auth.CredentialProvider.from_env_var!("MOMENTO_AUTH_TOKEN")

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Full example code and imports can be found here

If you're storing your Momento API key in a secret manager such as AWS Secret Manager, GCP Secret Manager, or a local config file, you must first retrieve the credentials from there and then instantiate a CredentialProvider from a string, like this:

JavaScript

const apiKey = retrieveApiKeyFromYourSecretsManager();
CredentialProvider.fromString({apiKey: apiKey});

info

Full example code and imports can be found here

Java

final String authToken = retrieveAuthTokenFromYourSecretsManager();
CredentialProvider.fromString(authToken);

info

Full example code and imports can be found here

Kotlin

val authToken = retrieveAuthTokenFromYourSecretsManager()
CredentialProvider.fromString(authToken)

info

Full example code and imports can be found here

Go

apiKey := RetrieveApiKeyFromYourSecretsManager()
credentialProvider, err = auth.NewStringMomentoTokenProvider(apiKey)
if err != nil {
	fmt.Println("Error parsing API key:", err)
}

info

Full example code and imports can be found here

Rust

  let _credential_provider = CredentialProvider::from_string("my-api-key".to_string());


allow(non_snake_case)]
b fn example_API_CredentialProviderFromEnvVar() {
  let _credential_provider = CredentialProvider::from_env_var("MOMENTO_API_KEY".to_string());


allow(non_snake_case)]
b fn example_API_ConfigurationLaptop() {
  let _config = momento::cache::configurations::Laptop::latest();


allow(non_snake_case)]
b fn example_API_ConfigurationInRegionDefaultLatest() {
  let _config = momento::cache::configurations::InRegion::latest();


allow(non_snake_case)]
b fn example_API_ConfigurationInRegionLowLatency() {
  let _config = momento::cache::configurations::LowLatency::latest();


allow(non_snake_case)]
b fn example_API_ConfigurationLambdaLatest() {
  let _config = momento::cache::configurations::Lambda::latest();


allow(non_snake_case)]
b fn example_API_InstantiateCacheClient() -> Result<(), MomentoError> {
  let _cache_client = CacheClient::builder()
      .default_ttl(Duration::from_secs(60))
      .configuration(Laptop::latest())
      .credential_provider(CredentialProvider::from_env_var(
          "MOMENTO_API_KEY".to_string(),
      )?)
      .build()?;

info

Full example code and imports can be found here

Elixir

auth_token = retrieve_auth_token_from_your_secrets_manager()
Momento.Auth.CredentialProvider.from_string!(auth_token)

info

Full example code and imports can be found here

For an example of how to retrieve credentials from AWS Secrets Manager, see Retrieving a Momento auth token from AWS Secrets Manager.

For general information on Momento authentication, see our auth page.

For more information, see our Response Objects page, and the docs for the specific SDK that you are using (under Develop->SDKs in the left nav).