How to chain two Spring Cloud Contracts

Question

I am trying to write a two Spring Cloud contracts using Groovy script. A field in the request body of the second contract (contract2) shall be the value of the 'cookie' field present in the response of the first contract (contract1). I am not able to extract the field from the response.

I tried to extract the 'cookie' from the response using String cookie = getBody().properties.get('data').properties.get('cookie') but it triggered compilation error. What can I try next?

 package contracts

import org.springframework.cloud.contract.spec.Contract

def contract1 = Contract.make {
    request {
        method 'POST'
        url '/contract1'
        headers {
            contentType('application/json')
        }
        body(["url"  : "test",
              "name": "test",
              "dnsServer": "8.8.8.8",                      
              "vlan"    : "52"])
    }
    response {
        status 200
        body("data" : ["cookie": anyNonBlankString()]])
        headers {
            contentType(applicationJson())
        }
    }
}
def contract2 = Contract.make {
    request {
        method 'POST'
        url '/contract2'
        headers {
            contentType('application/json')
        }
        body(["model"  : "test model",
              "cookie" : <shall be the cookie generated by the response of contract1>
              ])
    }
    response {
        status 200
    }
}
[contract1, contract2]

Edit 1

I added String cookie = getResponse().properties.get("data").properties.get("cookie") right after the 'response' block in 'contract1'. Then I did "mvn clean spring-cloud-contract:generateTests" from terminal. I got the below compilation error:

[ERROR] Exception occurred while trying to evaluate the contract at path [C:\neilb\pagination\workspace\src\test\resources\contracts\ve_lifecycle.groovy]
java.lang.NullPointerException: Cannot get property 'properties' on null object
    at org.codehaus.groovy.runtime.NullObject.getProperty (NullObject.java:60)
    at org.codehaus.groovy.runtime.InvokerHelper.getProperty (InvokerHelper.java:190)
    at org.codehaus.groovy.runtime.callsite.NullCallSite.getProperty (NullCallSite.java:46)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGetProperty (AbstractCallSite.java:298)
    at contracts.ve_lifecycle$_run_closure1.doCall (ve_lifecycle.groovy:31)
    at contracts.ve_lifecycle$_run_closure1.doCall (ve_lifecycle.groovy)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:567)
    at org.codehaus.groovy.reflection.CachedMethod.invoke (CachedMethod.java:101)
    at groovy.lang.MetaMethod.doMethodInvoke (MetaMethod.java:323)
    at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod (ClosureMetaClass.java:263)
    at groovy.lang.MetaClassImpl.invokeMethod (MetaClassImpl.java:1041)
    at groovy.lang.Closure.call (Closure.java:405)
    at groovy.lang.Closure.call (Closure.java:399)
    at org.springframework.cloud.contract.spec.Contract.make (Contract.java:180)
    at org.springframework.cloud.contract.spec.Contract$make.call (Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall (CallSiteArray.java:47)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call (AbstractCallSite.java:115)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call (AbstractCallSite.java:127)
    at contracts.ve_lifecycle.run (ve_lifecycle.groovy:5)
    at groovy.lang.GroovyShell.evaluate (GroovyShell.java:443)
    at groovy.lang.GroovyShell.evaluate (GroovyShell.java:490)
    at org.springframework.cloud.contract.verifier.util.ContractVerifierDslConverter.toObject (ContractVerifierDslConverter.groovy:141)
    at org.springframework.cloud.contract.verifier.util.ContractVerifierDslConverter.convertAsCollection (ContractVerifierDslConverter.groovy:99)
    at org.springframework.cloud.contract.verifier.file.ContractFileScanner.appendRecursively (ContractFileScanner.groovy:249)
    at org.springframework.cloud.contract.verifier.file.ContractFileScanner.findContractsRecursively (ContractFileScanner.groovy:221)
    at org.springframework.cloud.contract.verifier.TestGenerator.generateTestClasses (TestGenerator.groovy:125)
    at org.springframework.cloud.contract.verifier.TestGenerator.generate (TestGenerator.groovy:104)
    at org.springframework.cloud.contract.maven.verifier.GenerateTestsMojo.execute (GenerateTestsMojo.java:301)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke (Method.java:567)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)