github.com/replicatedcom/ship@v0.50.0/pkg/patch/patcher.go

package patch

import (
	"encoding/json"
	"path"
	"path/filepath"
	"reflect"
	"strconv"

	"github.com/ghodss/yaml"
	"github.com/go-kit/kit/log"
	"github.com/go-kit/kit/log/level"
	"github.com/pkg/errors"
	"github.com/spf13/afero"
	yamlv3 "gopkg.in/yaml.v3"
	"k8s.io/apimachinery/pkg/util/strategicpatch"
	"k8s.io/client-go/kubernetes/scheme"
	kustomizepatch "sigs.k8s.io/kustomize/pkg/patch"
	k8stypes "sigs.k8s.io/kustomize/pkg/types"

	"github.com/replicatedhq/ship/pkg/api"
	"github.com/replicatedhq/ship/pkg/util"
)

const PATCH_TOKEN = "TO_BE_MODIFIED"

const TempYamlPath = "temp.yaml"

type Patcher interface {
	CreateTwoWayMergePatch(original, modified []byte) ([]byte, error)
	MergePatches(original []byte, path []string, step api.Kustomize, resource string) ([]byte, error)
	ApplyPatch(patch []byte, step api.Kustomize, resource string) ([]byte, error)
	ModifyField(original []byte, path []string) ([]byte, error)
	RunKustomize(kustomizationPath string) ([]byte, error)
}

type ShipPatcher struct {
	Logger log.Logger
	FS     afero.Afero
}

func NewShipPatcher(logger log.Logger, fs afero.Afero) Patcher {
	return &ShipPatcher{
		Logger: logger,
		FS:     fs,
	}
}

func (p *ShipPatcher) writeHeaderToPatch(originalJSON, patchJSON []byte) ([]byte, error) {
	original := map[string]interface{}{}
	patch := map[string]interface{}{}

	err := json.Unmarshal(originalJSON, &original)
	if err != nil {
		return nil, errors.Wrap(err, "unmarshal original json")
	}

	err = json.Unmarshal(patchJSON, &patch)
	if err != nil {
		return nil, errors.Wrap(err, "unmarshal patch json")
	}

	originalAPIVersion, ok := original["apiVersion"]
	if !ok {
		return nil, errors.New("no apiVersion key present in original")
	}

	originalKind, ok := original["kind"]
	if !ok {
		return nil, errors.New("no kind key present in original")
	}

	originalMetadata, ok := original["metadata"]
	if !ok {
		return nil, errors.New("no metadata key present in original")
	}

	patch["apiVersion"] = originalAPIVersion
	patch["kind"] = originalKind
	patch["metadata"] = originalMetadata

	modifiedPatch, err := json.Marshal(patch)
	if err != nil {
		return nil, errors.Wrap(err, "marshal modified patch json")
	}

	return modifiedPatch, nil
}

func (p *ShipPatcher) CreateTwoWayMergePatch(original, modified []byte) ([]byte, error) {
	debug := level.Debug(log.With(p.Logger, "struct", "patcher", "handler", "createTwoWayMergePatch"))

	debug.Log("event", "convert.original")
	originalJSON, err := yaml.YAMLToJSON(original)
	if err != nil {
		return nil, errors.Wrap(err, "convert original file to json")
	}

	debug.Log("event", "convert.modified")
	modifiedJSON, err := yaml.YAMLToJSON(modified)
	if err != nil {
		return nil, errors.Wrap(err, "convert modified file to json")
	}

	debug.Log("event", "createKubeResource.original")
	r, err := util.NewKubernetesResource(originalJSON)
	if err != nil {
		return nil, errors.Wrap(err, "create kube resource with original json")
	}

	versionedObj, err := scheme.Scheme.New(util.ToGroupVersionKind(r.Id().Gvk()))
	if err != nil {
		return nil, errors.Wrap(err, "read group, version kind from kube resource")
	}

	patchBytes, err := strategicpatch.CreateTwoWayMergePatch(originalJSON, modifiedJSON, versionedObj)
	if err != nil {
		return nil, errors.Wrap(err, "create two way merge patch")
	}

	modifiedPatchJSON, err := p.writeHeaderToPatch(originalJSON, patchBytes)
	if err != nil {
		return nil, errors.Wrap(err, "write original header to patch")
	}

	patch, err := yaml.JSONToYAML(modifiedPatchJSON)
	if err != nil {
		return nil, errors.Wrap(err, "convert merge patch json to yaml")
	}

	return patch, nil
}

func (p *ShipPatcher) MergePatches(original []byte, path []string, step api.Kustomize, resource string) ([]byte, error) {
	debug := level.Debug(log.With(p.Logger, "struct", "patcher", "handler", "mergePatches"))

	debug.Log("event", "applyPatch")
	modified, err := p.ApplyPatch(original, step, resource)
	if err != nil {
		return nil, errors.Wrap(err, "apply patch")
	}

	debug.Log("event", "modifyField")
	dirtied, err := p.ModifyField(modified, path)
	if err != nil {
		return nil, errors.Wrap(err, "dirty modified")
	}

	debug.Log("event", "readOriginal")
	originalYaml, err := p.FS.ReadFile(resource)
	if err != nil {
		return nil, errors.Wrap(err, "read original yaml")
	}

	debug.Log("event", "createNewPatch")
	finalPatch, err := p.CreateTwoWayMergePatch(originalYaml, dirtied)
	if err != nil {
		return nil, errors.Wrap(err, "create patch")
	}

	return finalPatch, nil
}

func (p *ShipPatcher) ApplyPatch(patch []byte, step api.Kustomize, resource string) ([]byte, error) {
	debug := level.Debug(log.With(p.Logger, "struct", "patcher", "handler", "applyPatch"))

	defer p.deleteTempKustomization(step)

	if err := p.FS.MkdirAll(step.TempRenderPath(), 0777); err != nil {
		return nil, errors.Wrap(err, "ensure temp patch overlay dir exists")
	}

	debug.Log("event", "writeFile.tempPatch")
	if err := p.FS.WriteFile(path.Join(step.TempRenderPath(), TempYamlPath), patch, 0755); err != nil {
		return nil, errors.Wrap(err, "write temp patch overlay")
	}

	debug.Log("event", "relPath")
	relativePathToResource, err := filepath.Rel(step.TempRenderPath(), resource)
	if err != nil {
		return nil, errors.Wrap(err, "failed to find relative path")
	}

	kustomizationYaml := k8stypes.Kustomization{
		Resources:             []string{relativePathToResource},
		PatchesStrategicMerge: []kustomizepatch.StrategicMerge{TempYamlPath},
	}

	kustomizationYamlBytes, err := yamlv3.Marshal(kustomizationYaml)
	if err != nil {
		return nil, errors.Wrap(err, "marshal kustomization yaml")
	}

	debug.Log("event", "writeFile.tempKustomizationYaml")
	if err := p.FS.WriteFile(path.Join(step.TempRenderPath(), "kustomization.yaml"), kustomizationYamlBytes, 0755); err != nil {
		return nil, errors.Wrap(err, "write temp kustomization yaml")
	}

	debug.Log("event", "run.kustomizeBuild")
	merged, err := p.RunKustomize(step.TempRenderPath())
	if err != nil {
		return nil, err
	}

	return merged, nil
}

func (p *ShipPatcher) deleteTempKustomization(step api.Kustomize) error {
	debug := level.Debug(log.With(p.Logger, "struct", "patcher", "handler", "deleteTempKustomization"))

	tempKustomizationPath := path.Join(step.TempRenderPath(), "kustomization.yaml")

	debug.Log("event", "remove.tempKustomizationYaml")
	err := p.FS.Remove(tempKustomizationPath)
	if err != nil {
		return errors.Wrap(err, "remove temp base kustomization.yaml")
	}

	err = p.FS.Remove(path.Join(step.TempRenderPath(), TempYamlPath))
	if err != nil {
		return errors.Wrap(err, "remove temp patch yaml")
	}

	return nil
}

func (p *ShipPatcher) ModifyField(original []byte, path []string) ([]byte, error) {
	debug := level.Debug(log.With(p.Logger, "struct", "patcher", "handler", "modifyField"))

	originalMap := map[string]interface{}{}

	debug.Log("event", "convert original yaml to json")
	originalJSON, err := yaml.YAMLToJSON(original)
	if err != nil {
		return nil, errors.Wrap(err, "original yaml to json")
	}

	debug.Log("event", "unmarshal original yaml")
	if err := json.Unmarshal(originalJSON, &originalMap); err != nil {
		return nil, errors.Wrap(err, "unmarshal original yaml")
	}

	debug.Log("event", "modify field")
	modified, err := p.modifyField(originalMap, []string{}, path)
	if err != nil {
		return nil, errors.Wrap(err, "error modifying value")
	}

	debug.Log("event", "marshal modified")
	modifiedJSON, err := json.Marshal(modified)
	if err != nil {
		return nil, errors.Wrap(err, "marshal modified json")
	}

	debug.Log("event", "convert modified yaml to json")
	modifiedYAML, err := yaml.JSONToYAML(modifiedJSON)
	if err != nil {
		return nil, errors.Wrap(err, "modified json to yaml")
	}

	return modifiedYAML, nil
}

func (p *ShipPatcher) modifyField(original interface{}, current []string, path []string) (interface{}, error) {
	originalType := reflect.TypeOf(original)
	if original == nil {
		return nil, nil
	}
	switch originalType.Kind() {
	case reflect.Map:
		typedOriginal, ok := original.(map[string]interface{})
		modifiedMap := make(map[string]interface{})
		if !ok {
			return nil, errors.New("error asserting map")
		}
		for key, value := range typedOriginal {
			modifiedValue, err := p.modifyField(value, append(current, key), path)
			if err != nil {
				return nil, err
			}
			modifiedMap[key] = modifiedValue
		}
		return modifiedMap, nil
	case reflect.Slice:
		typedOriginal, ok := original.([]interface{})
		modifiedSlice := make([]interface{}, len(typedOriginal))
		if !ok {
			return nil, errors.New("error asserting slice")
		}
		for key, value := range typedOriginal {
			modifiedValue, err := p.modifyField(value, append(current, strconv.Itoa(key)), path)
			if err != nil {
				return nil, err
			}
			modifiedSlice[key] = modifiedValue
		}
		return modifiedSlice, nil
	default:
		for idx := range path {
			if current[idx] != path[idx] {
				return original, nil
			}
		}
		return PATCH_TOKEN, nil
	}
}