Terratest Helm Charts fail in Go unit tests

php Editor Strawberry discovered that Terratest Helm Charts often encountered failure problems in Go unit tests. Terratest is a Go library for writing automated, repeatable infrastructure tests, and Helm Charts is a package management tool for Kubernetes. When using Terratest for unit testing of Helm Charts, various problems sometimes occur, causing the test to fail. This article will explore the causes of these problems and provide corresponding solutions to help developers better deal with these challenges. Whether you are a beginner or an experienced developer, you can gain useful knowledge and skills from this article.

Question content

I'm trying to use terratest to unit test my helm chart, but I'm getting a strange error:

This is my unit test:

package grafana

import (
    "fmt"

    "testing"

    corev1 "k8s.io/api/core/v1"

    "github.com/gruntwork-io/terratest/modules/helm"
)

func testgrafanahelmcharttemplate(t *testing.t) {
    // path to the helm chart we will test
    helmchartgrafanapath := "../../../open-electrons-monitoring"

    // setup the args. for this test, we will set the following input values:
    // - image=grafana:latest
    options := &helm.options{
        setvalues: map[string]string{"image": "grafana:latest"},
    }

    // run rendertemplate to render the template and capture the output.
    output := helm.rendertemplate(t, options, helmchartgrafanapath, "pod", []string{"templates/grafana/grafana-deployment.yml"})

    // now we use kubernetes/client-go library to render the template output into the pod struct. this will
    // ensure the pod resource is rendered correctly.
    var pod corev1.pod
    helm.unmarshalk8syaml(t, output, &pod)

    // finally, we verify the pod spec is set to the expected container image value
    expectedcontainerimage := "grafana:latest"
    podcontainers := pod.spec.containers
    fmt.print(pod.spec)
    fmt.print("*********************************************************")
    if podcontainers[0].image != expectedcontainerimage {
        t.fatalf("rendered container image (%s) is not expected (%s)", podcontainers[0].image, expectedcontainerimage)
    }
}

The following is the output of the deployment:

testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66: apiversion: apps/v1
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66: kind: deployment
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66: metadata:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:   name: grafana-open-electrons-monitoring
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:   namespace: open-electrons-monitoring-ns
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:   labels:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     app.kubernetes.io/name: open-electrons-grafana
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     app.kubernetes.io/component: monitoring
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     app.kubernetes.io/part-of: open-electrons-grafana
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     app.kubernetes.io/managed-by: helm
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     app.kubernetes.io/instance: open-electrons-grafana
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     app.kubernetes.io/version: refs/tags/v0.0.11 # todo: better use the grafana version
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66: spec:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:   replicas: 1
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:   selector:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     matchlabels:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       app: open-electrons-grafana
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:   strategy:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     rollingupdate:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       maxsurge: 1
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       maxunavailable: 1
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     type: rollingupdate
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:   template:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     metadata:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       creationtimestamp: null
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       labels:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         name: open-electrons-grafana
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:     spec:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       securitycontext:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         runasuser: 1000
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         runasgroup: 3000
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         fsgroup: 2000
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         runasnonroot: true
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       containers:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         - image: grafana/grafana:latest
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:           imagepullpolicy: ifnotpresent
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:           name: open-electrons-grafana
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:           ports:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:             - containerport: 3000
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               protocol: tcp
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:           resources:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:             limits:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               memory: "1gi"
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               cpu: "1000m"
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:             requests:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               memory: 500m
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               cpu: "500m"
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:           volumemounts:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:             - mountpath: /var/lib/grafana
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               name: grafana-storage
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:             - mountpath: /etc/grafana/provisioning/datasources
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               name: grafana-datasources
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:               readonly: false
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       restartpolicy: always
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       terminationgraceperiodseconds: 30
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:       volumes:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         - name: grafana-storage
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:           emptydir: {}
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:         - name: grafana-datasources
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:           configmap:
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:             defaultmode: 420
testgrafanahelmcharttemplate 2023-02-12t18:59:01+01:00 logger.go:66:             name: grafana-datasources
{[] [] [] []  <nil> <nil>  map[]   <nil>  false false false <nil> nil []   nil  [] []  <nil> nil [] <nil> <nil> <nil> map[] [] <nil>}*********************************************************--- fail: testgrafanahelmcharttemplate (0.06s)

This is the output:

panic: runtime error: index out of range [0] with length 0 [recovered]
    panic: runtime error: index out of range [0] with length 0

goroutine 5 [running]:
testing.tRunner.func1.2({0x1440620, 0xc0002a85b8})
    /usr/local/go/src/testing/testing.go:1526 +0x24e
testing.tRunner.func1()
    /usr/local/go/src/testing/testing.go:1529 +0x39f
panic({0x1440620, 0xc0002a85b8})
    /usr/local/go/src/runtime/panic.go:884 +0x213

Why did it fail? What am I missing here?

Solution

I managed to fix it. The import should look like this:

appsv1 "k8s.io/api/apps/v1"

Then I have to modify the instantiation of the deployment object:

var deployment appsv1.Deployment

Instead of pod object.

The above is the detailed content of Terratest Helm Charts fail in Go unit tests. For more information, please follow other related articles on the PHP Chinese website!