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() }