Configuration providers

configure will try a number of different location to find a configuration provider. It will attempt to read a file or dynamo table in the following order.

• Java System property 1config.file, if set and the file exists it will be used as sole configuration
• Environment variable $ONECONFIG_FILE, if set and the file exists it will be used as sole configuration
• Java Resource bundle 1config.edn (or .json, .txt, .properties), if present it will be used as sole configuration
• ~/.1config/<service-key>/<env>/<version>/<service-key>.<ext> (home dir) - if present it will be used as configuration. Entries in the ~/.1config/ will have precendence over the DynamoDB table.
• DynamoDB table called 1Config in the "current" region.

The name of the DynamoDB table can be customized with $ONECONFIG_DYNAMO_TABLE environment variable (or 1config.dynamo.table property). It will use the machine role to access the database. The AWS region can be controlled via the environment variable $AWS_REGION. For the AWS credentials we use the Default Credential Provider Chain. Therefore the credentials can be provided in one of the following ways:

• Environment Variables – AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY. The AWS SDK for Java uses the EnvironmentVariableCredentialsProvider class to load these credentials.

• Java System Properties – aws.accessKeyId and aws.secretKey. The AWS SDK for Java uses the SystemPropertiesCredentialsProvider to load these credentials.

• The default credential profiles file – typically located at ~/.aws/credentials (this location may vary per platform), this credentials file is shared by many of the AWS SDKs and by the AWS CLI. The AWS SDK for Java uses the ProfileCredentialsProvider to load these credentials.

  You can create a credentials file by using the aws configure command provided by the AWS CLI, or you can create it by hand-editing the file with a text editor. For information about the credentials file format, see AWS Credentials File Format.

• Instance profile credentials – these credentials can be used on EC2 instances, and are delivered through the Amazon EC2 metadata service. The AWS SDK for Java uses the InstanceProfileCredentialsProvider to load these credentials.