[[sec:build_script]]
== Build scripts

The build script is either a `build.gradle` file written in Groovy or a `build.gradle.kts` file in Kotlin.

The link:{groovyDslPath}/index.html[Groovy DSL^] and the link:{kotlinDslPath}/index.html[Kotlin DSL^] are the only accepted languages for Gradle scripts.

Let's take a look at an example and break it down:

====
[.multi-language-sample]
=====
.build.gradle.kts

apiVersion: release-notes/v2
kind: feature
area: traffic-management

releaseNotes:
- |

{{ $gateway := index .Values "gateways" "istio-ingressgateway" }}
{{- if not $gateway.customService }}
apiVersion: v1
kind: Service
metadata:
  name: {{ $gateway.name }}
  namespace: {{ .Release.Namespace }}
  annotations:
    {{- range $key, $val := $gateway.serviceAnnotations }}
    {{ $key }}: {{ $val | quote }}
    {{- end }}
  labels:
{{ $gateway.labels | toYaml | indent 4 }}
    release: {{ .Release.Name }}

	MOVOU	(AX), X1
	PCMPEQB	X0, X1
	PMOVMSKB X1, DX
	BSFL	DX, DX
	JNZ	ssesuccess

failure:
	MOVQ $-1, (R8)
	RET

// We've found a chunk containing the byte.
// The chunk was loaded from DI.
// The index of the matching byte in the chunk is DX.
// The start of the data is SI.
ssesuccess:
	SUBQ SI, DI	// Compute offset of chunk within data.
	ADDQ DX, DI	// Add offset of byte within chunk.
	MOVQ DI, (R8)
	RET

{{ $gateway := index .Values "gateways" "istio-egressgateway" }}
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: {{ $gateway.name }}-sds
  namespace: {{ .Release.Namespace }}
  labels:
    release: {{ .Release.Name }}
    istio.io/rev: {{ .Values.revision | default "default" | quote }}
    install.operator.istio.io/owning-resource: {{ .Values.ownerName | default "unknown" }}
    operator.istio.io/component: "EgressGateways"
rules:

{{ $gateway := index .Values "gateways" "istio-ingressgateway" }}
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: {{ $gateway.name }}-sds
  namespace: {{ .Release.Namespace }}
  labels:
    release: {{ .Release.Name }}
    istio.io/rev: {{ .Values.revision | default "default" | quote }}
    install.operator.istio.io/owning-resource: {{ .Values.ownerName | default "unknown" }}
    operator.istio.io/component: "IngressGateways"
rules:

    }
}
----
<1> You can use the link:{kotlinDslPath}/gradle/org.gradle.api.tasks/-task-container/index.html[register()] method to create new tasks.
<2> You can use the link:{kotlinDslPath}/gradle/org.gradle.api.tasks/-task-collection/index.html[named()] method to configure existing tasks.
=====
[.multi-language-sample]
=====
.app/build.gradle
[source, groovy]
----

{{- if .Values.global.defaultPodDisruptionBudget.enabled }}
{{ $gateway := index .Values "gateways" "istio-egressgateway" }}
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
  name: {{ $gateway.name }}
  namespace: {{ .Release.Namespace }}
  labels:
{{ $gateway.labels | toYaml | trim | indent 4 }}
    release: {{ .Release.Name }}
    istio.io/rev: {{ .Values.revision | default "default" | quote }}

//go:build gc

#include "textflag.h"

// func stfle() facilityList
TEXT ·stfle(SB), NOSPLIT|NOFRAME, $0-32
	MOVD $ret+0(FP), R1
	MOVD $3, R0          // last doubleword index to store
	XC   $32, (R1), (R1) // clear 4 doublewords (32 bytes)
	WORD $0xb2b01000     // store facility list extended (STFLE)
	RET

// func kmQuery() queryResult
TEXT ·kmQuery(SB), NOSPLIT|NOFRAME, $0-16

// license that can be found in the LICENSE file.

#include "textflag.h"

// func stfle() facilityList
TEXT ·stfle(SB), NOSPLIT|NOFRAME, $0-32
	MOVD $ret+0(FP), R1
	MOVD $3, R0          // last doubleword index to store
	XC   $32, (R1), (R1) // clear 4 doublewords (32 bytes)
	WORD $0xb2b01000     // store facility list extended (STFLE)
	RET

// func kmQuery() queryResult
TEXT ·kmQuery(SB), NOSPLIT|NOFRAME, $0-16