Spring Expression Language Tricks
Introduction
Spinnaker uses the Spring Expression Language (SpEL) for pipeline expressions, so you can do a lot of interesting things with Spinnaker expressions. Here are a couple of the more interesting examples that we’ve come across (this page will grow)
Prerequisites
N/A
Instructions
Basic Math
Take the number of instances for a deployment and multiply by a non-integer value:Note: “Get Deployment” is the name of the “Find Artifacts from Resource (Manifest)” stage that looks at a Kubernetes deployment object.
${ (0.8 * #stage("Get Deployment")["outputs"]["manifest"]["spec"]["replicas"]).intValue() }
Helper Properties
Create a parameter environment with 3 options
Access the value of the variable via a helper property, in this case, parameter. For example:
The environment is: ${ parameters.environment }
Some Helper Properties are already defined, for example:
The execution id is automatically set: ${execution['id']}
Helper Functions
Read and print a JSON, for example:
${#readJson('{"development": "dev", "staging": "stage", "production":"prod"}').toString()}
You can also access a value in the JSON with the environment parameter from the Helper Properties Section:
${#readJson('{"development": "dev", "staging": "stage", "production":"prod"}')[parameters.environment]}
Ternary Operator
? :
Simple example:
${ true ? "True text" : "False text" }
Example (in the text of a Manual Judgement stage), where Get Service is a “Find Artifacts From Resource (Manifest)” that looks at a Kubernetes service object:
The loadBalancer ingress is ${ #stage("Get Service")["outputs"]["manifest"]["status"]["loadBalancer"].containsKey("ingress") ? "ready" : "not ready" }.
Whitelisted Java Classes
Some Java classes are available for use in SpEL expressions (see Spinnaker Reference Docs)For example, generating the current date in MM-dd-yyyy format:
${new java.text.SimpleDateFormat("MM-dd-yyyy").format(new java.util.Date())}
Sometimes you may want to call a static method. For example, to generate a UUID:
${T(java.util.UUID).randomUUID() }