Files
kustomize/kyaml/setters2/settersutil/substitutioncreator.go
2020-07-30 12:51:57 -07:00

416 lines
13 KiB
Go

// Copyright 2019 The Kubernetes Authors.
// SPDX-License-Identifier: Apache-2.0
package settersutil
import (
"fmt"
"io/ioutil"
"os"
"regexp"
"strings"
"github.com/go-openapi/spec"
"sigs.k8s.io/kustomize/kyaml/errors"
"sigs.k8s.io/kustomize/kyaml/fieldmeta"
"sigs.k8s.io/kustomize/kyaml/kio"
"sigs.k8s.io/kustomize/kyaml/openapi"
"sigs.k8s.io/kustomize/kyaml/sets"
"sigs.k8s.io/kustomize/kyaml/setters2"
"sigs.k8s.io/kustomize/kyaml/yaml"
)
// SubstitutionCreator creates or updates a substitution in the OpenAPI definitions, and
// inserts references to the substitution from matching resource fields.
type SubstitutionCreator struct {
// Name is the name of the substitution to create
Name string
// Pattern is the substitution pattern
Pattern string
// Values are the substitution values for the pattern
Values []setters2.Value
// FieldName if set will add the OpenAPI reference to fields with this name or path
// FieldName may be the full name of the field, full path to the field, or the path suffix.
// e.g. all of the following would match spec.template.spec.containers.image --
// [image, containers.image, spec.containers.image, template.spec.containers.image,
// spec.template.spec.containers.image]
// Optional. If unspecified match all field names.
FieldName string
// FieldValue if set will add the OpenAPI reference to fields if they have this value.
// Optional. If unspecified match all field values.
FieldValue string
// Path to openAPI file
OpenAPIPath string
// Path to resources folder
ResourcesPath string
}
func (c *SubstitutionCreator) Filter(input []*yaml.RNode) ([]*yaml.RNode, error) {
return nil, c.Create(c.OpenAPIPath, c.ResourcesPath)
}
func (c SubstitutionCreator) Create(openAPIPath, resourcesPath string) error {
values, err := markersAndRefs(c.Name, c.Pattern)
if err != nil {
return err
}
c.Values = values
d := setters2.SubstitutionDefinition{
Name: c.Name,
Values: c.Values,
Pattern: c.Pattern,
}
// the input substitution definition is updated in the openAPI file and then parsed
// to check if there are any cycles in nested substitutions, if there are
// any, the openAPI file will be reverted to current state and error is thrown
stat, err := os.Stat(openAPIPath)
if err != nil {
return err
}
curOpenAPI, err := ioutil.ReadFile(openAPIPath)
if err != nil {
return err
}
if err := d.AddToFile(openAPIPath); err != nil {
return err
}
// Load the updated definitions
if err := openapi.AddSchemaFromFile(openAPIPath); err != nil {
return err
}
visited := sets.String{}
ref, err := spec.NewRef(fieldmeta.DefinitionsPrefix + fieldmeta.SubstitutionDefinitionPrefix + c.Name)
if err != nil {
return err
}
schema, err := openapi.Resolve(&ref)
if err != nil {
return err
}
ext, err := setters2.GetExtFromSchema(schema)
if err != nil {
return err
}
err = c.CreateSettersForSubstitution(openAPIPath)
if err != nil {
return err
}
// Load the updated definitions after setters are created
if err := openapi.AddSchemaFromFile(openAPIPath); err != nil {
return err
}
// revert openAPI file if there are cycles detected in created input substitution
if err := checkForCycles(ext, visited); err != nil {
if writeErr := ioutil.WriteFile(openAPIPath, curOpenAPI, stat.Mode().Perm()); writeErr != nil {
return writeErr
}
return err
}
// Update the resources with the setter reference
inout := &kio.LocalPackageReadWriter{PackagePath: resourcesPath}
return kio.Pipeline{
Inputs: []kio.Reader{inout},
Filters: []kio.Filter{kio.FilterAll(
&setters2.Add{
FieldName: c.FieldName,
FieldValue: c.FieldValue,
Ref: fieldmeta.DefinitionsPrefix + fieldmeta.SubstitutionDefinitionPrefix + c.Name,
})},
Outputs: []kio.Writer{inout},
}.Execute()
}
// createMarkersAndRefs takes the input pattern, creates setter/substitution markers
// and corresponding openAPI refs
func markersAndRefs(substName, pattern string) ([]setters2.Value, error) {
var values []setters2.Value
// extract setter name tokens from pattern enclosed in ${}
re := regexp.MustCompile(`\$\{([^}]*)\}`)
markers := re.FindAllString(pattern, -1)
if len(markers) == 0 {
return nil, errors.Errorf("unable to find setter or substitution names in pattern, " +
"setter names must be enclosed in ${}")
}
for _, marker := range markers {
name := strings.TrimSuffix(strings.TrimPrefix(marker, "${"), "}")
if name == substName {
return nil, fmt.Errorf("setters must have different name than the substitution: %s", name)
}
ref, err := spec.NewRef(fieldmeta.DefinitionsPrefix + fieldmeta.SubstitutionDefinitionPrefix + name)
if err != nil {
return nil, err
}
var markerRef string
subst, _ := openapi.Resolve(&ref)
// check if the substitution exists with the marker name or fall back to creating setter
// ref with the name
if subst != nil {
markerRef = fieldmeta.DefinitionsPrefix + fieldmeta.SubstitutionDefinitionPrefix + name
} else {
markerRef = fieldmeta.DefinitionsPrefix + fieldmeta.SetterDefinitionPrefix + name
}
values = append(
values,
setters2.Value{Marker: marker, Ref: markerRef},
)
}
return values, nil
}
// CreateSettersForSubstitution creates the setters for all the references in the substitution
// values if they don't already exist in openAPIPath file.
func (c SubstitutionCreator) CreateSettersForSubstitution(openAPIPath string) error {
y, err := yaml.ReadFile(openAPIPath)
if err != nil {
return err
}
m, err := c.GetValuesForMarkers()
if err != nil {
return err
}
// for each ref in values, check if the setter or substitution already exists, if not create setter
for _, value := range c.Values {
// continue if ref is a substitution, as it has already been checked if it exists
// as part of preRunE
if strings.Contains(value.Ref, fieldmeta.SubstitutionDefinitionPrefix) {
fmt.Printf("found a substitution with name %s\n", value.Marker)
continue
}
setterObj, err := y.Pipe(yaml.Lookup(
// get the setter key from ref. Ex: from #/definitions/io.k8s.cli.setters.image_setter
// extract io.k8s.cli.setters.image_setter
"openAPI", "definitions", strings.TrimPrefix(value.Ref, fieldmeta.DefinitionsPrefix)))
if err != nil {
return err
}
if setterObj == nil {
name := strings.TrimPrefix(value.Ref, fieldmeta.DefinitionsPrefix+fieldmeta.SetterDefinitionPrefix)
value := m[value.Marker]
fmt.Printf("unable to find setter with name %s, creating new setter with value %s\n", name, value)
sd := setters2.SetterDefinition{
// get the setter name from ref. Ex: from #/definitions/io.k8s.cli.setters.image_setter
// extract image_setter
Name: name,
Value: value,
}
err := sd.AddToFile(openAPIPath)
if err != nil {
return err
}
}
}
return nil
}
func checkForCycles(ext *setters2.CliExtension, visited sets.String) error {
// check if the substitution has already been visited and throw error as cycles
// are not allowed in nested substitutions
if visited.Has(ext.Substitution.Name) {
return errors.Errorf(
"cyclic substitution detected with name " + ext.Substitution.Name)
}
visited.Insert(ext.Substitution.Name)
// substitute each setter into the pattern to get the new value
// if substitution references to another substitution, recursively
// process the nested substitutions to replace the pattern with setter values
for _, v := range ext.Substitution.Values {
if v.Ref == "" {
return errors.Errorf(
"missing reference on substitution " + ext.Substitution.Name)
}
ref, err := spec.NewRef(v.Ref)
if err != nil {
return errors.Wrap(err)
}
def, err := openapi.Resolve(&ref) // resolve the def to its openAPI def
if err != nil {
return errors.Wrap(err)
}
defExt, err := setters2.GetExtFromSchema(def) // parse the extension out of the openAPI
if err != nil {
return errors.Wrap(err)
}
if defExt.Substitution != nil {
// parse recursively if it reference is substitution
err := checkForCycles(defExt, visited)
if err != nil {
return err
}
}
}
return nil
}
// GetValuesForMarkers parses the pattern and field value to derive values for the
// markers in the pattern string. Returns error if the marker values can't be derived
func (c SubstitutionCreator) GetValuesForMarkers() (map[string]string, error) {
m := make(map[string]string)
indices, err := c.GetStartIndices()
if err != nil {
return nil, err
}
fv := c.FieldValue
pattern := c.Pattern
fvInd := 0
patternInd := 0
// iterate fv, pattern with indices fvInd, patternInd respectively and when patternInd hits the index of a marker,
// freeze patternInd and iterate fvInd and capture string till we find the substring just after current marker
// and before next marker
// Ex: fv = "something/ubuntu:0.1.0", pattern = "something/IMAGE:VERSION", till patternInd reaches 10
// just proceed fvInd and patternInd and check if fv[fvInd]==pattern[patternInd] when patternInd is 10,
// freeze patternInd and move fvInd till it sees substring ':' which derives IMAGE = ubuntu and so on.
for fvInd < len(fv) && patternInd < len(pattern) {
// if we hit marker index, extract its corresponding value
if marker, ok := indices[patternInd]; ok {
// increment the patternInd to end of marker. This helps us to extract the substring before next marker.
patternInd += len(marker)
var value string
if value, fvInd, err = c.extractValueForMarker(fvInd, fv, patternInd, indices); err != nil {
return nil, err
}
// if marker is repeated in the pattern, make sure that the corresponding values
// are same and throw error if not.
if prevValue, ok := m[marker]; ok && prevValue != value {
return nil, errors.Errorf(
"marker %s is found to have different values %s and %s", marker, prevValue, value)
}
m[marker] = value
} else {
// Ex: fv = "samething/ubuntu:0.1.0" pattern = "something/IMAGE:VERSION". Error out at 'a' in fv.
if fv[fvInd] != pattern[patternInd] {
return nil, errors.Errorf(
"unable to derive values for markers, " +
"create setters for all markers and then try again")
}
fvInd++
patternInd++
}
}
// check if both strings are completely visited or throw error
if fvInd < len(fv) || patternInd < len(pattern) {
return nil, errors.Errorf(
"unable to derive values for markers, " +
"create setters for all markers and then try again")
}
return m, nil
}
// GetStartIndices returns the start indices of all the markers in the pattern
func (c SubstitutionCreator) GetStartIndices() (map[int]string, error) {
indices := make(map[int]string)
for _, value := range c.Values {
found := false
for i := range c.Pattern {
if strings.HasPrefix(c.Pattern[i:], value.Marker) {
indices[i] = value.Marker
found = true
}
}
if !found {
return nil, errors.Errorf("unable to find marker " + value.Marker + " in the pattern")
}
}
if err := validateMarkers(indices); err != nil {
return nil, err
}
return indices, nil
}
// validateMarkers takes the indices map, checks if any of 2 markers not have delimiters,
// checks if any marker is substring of other and returns error
func validateMarkers(indices map[int]string) error {
for k1, v1 := range indices {
for k2, v2 := range indices {
if k1 != k2 && k1+len(v1) == k2 {
return errors.Errorf(
"markers %s and %s are found to have no delimiters between them,"+
" pre-create setters and try again", v1, v2)
}
if v1 != v2 && strings.Contains(v1, v2) {
return errors.Errorf(
"markers %s is substring of %s,"+
" no marker should be substring of other", v2, v1)
}
}
}
return nil
}
// extractValueForMarker returns the value string for a marker and the incremented index
func (c SubstitutionCreator) extractValueForMarker(fvInd int, fv string, patternInd int, indices map[int]string) (string, int, error) {
nonMarkerStr := strTillNextMarker(indices, patternInd, c.Pattern)
// return the remaining string of fv till end if patternInd is at end of pattern
if patternInd == len(c.Pattern) {
return fv[fvInd:], len(fv), nil
}
// split remaining fv starting from fvInd with the non marker substring delimiter and get the first value
// In example fv = "something/ubuntu::0.1.0", pattern = "something/IMAGE::VERSION",
// split with "::" delimiter in fv which gives markerValue = ubuntu for marker IMAGE
// increment fvInd by length of extracted marker value and return fvInd
if markerValues := strings.Split(fv[fvInd:], nonMarkerStr); len(markerValues) > 0 {
return markerValues[0], fvInd + len(markerValues[0]), nil
}
return "", -1, errors.Errorf(
"unable to derive values for markers," +
" create setters for all markers and then try again")
}
// substrOfLen takes a string, start index and length and returns substring of given length
// or till end of string
func substrOfLen(str string, startInd int, length int) string {
return str[startInd:min(len(str), startInd+length)]
}
// strTillNextMarker takes in the indices map, a start index and returns the substring till
// start of next marker
func strTillNextMarker(indices map[int]string, startInd int, pattern string) string {
// initialize with max value which is length of pattern
nextMarkerStartInd := len(pattern)
for ind := range indices {
if ind > startInd {
nextMarkerStartInd = min(ind-startInd, nextMarkerStartInd)
}
}
return substrOfLen(pattern, startInd, nextMarkerStartInd)
}
func min(a int, b int) int {
if a < b {
return a
}
return b
}