Problem:
There are multiple ways to set a parameter store value. Which one should I use?
Solution:
1. Set parameter at deploy time:
Use this pattern when you want to create or update a plain-text SSM parameter during deployment. Creates an AWS::SSM::Parameter resource that resolves at deploy time.
new ssm.StringParameter(this, 'Param', {
parameterName: '/my/plain/parameter',
stringValue: 'my-value',
});
2. Set parameter with a JSON value:
Use when you need to store structured data (e.g., configuration or mapping) as a JSON string.
The object is serialized with JSON.stringify() before being written to SSM.
new ssm.StringParameter(this, 'JsonParam', {
parameterName: '/app/config',
stringValue: JSON.stringify({
apiUrl: 'https://api.example.com',
featureFlags: { enableNewUI: true, betaAccess: false },
}),
});
To read it back, retrieve the value and parse it:.
const config = JSON.parse(ssm.StringParameter
.fromStringParameterAttributes(this, 'JsonParamRef', {
parameterName: '/app/config',
})
.stringValue);
3. Set parameter with a lazy value:
Use when the parameter value depends on another construct (e.g., a pipeline name) and must be evaluated dynamically at synth. cdk.Lazy defers the value computation until synthesis.
new ssm.StringParameter(this, 'LazyParam', {
parameterName: '/pipeline/name',
stringValue: cdk.Lazy.string({
produce: () => pipeline.pipeline.pipelineName,
}),
});