feat: add --set-json flag to set json values.

When used with helm install, helm template, helm upgrade, it enables
to set json values (scalars/objects/arrays) from the command line.

Closes #10428

Signed-off-by: Luca Di Rocco <lucadirocco@gmail.com>

cmd/helm/flags.go

@@ -47,6 +47,7 @@ func addValueOptionsFlags(f *pflag.FlagSet, v *values.Options) {
 	f.StringArrayVar(&v.Values, "set", []string{}, "set values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)")
 	f.StringArrayVar(&v.StringValues, "set-string", []string{}, "set STRING values on the command line (can specify multiple or separate values with commas: key1=val1,key2=val2)")
 	f.StringArrayVar(&v.FileValues, "set-file", []string{}, "set values from respective files specified via the command line (can specify multiple or separate values with commas: key1=path1,key2=path2)")
+	f.StringArrayVar(&v.JSONValues, "set-json", []string{}, "set JSON values on the command line (can specify multiple or separate values with commas: key1=jsonval1,key2=jsonval2)")
 }
 
 func addChartPathOptionsFlags(f *pflag.FlagSet, c *action.ChartPathOptions) {

cmd/helm/install.go

@@ -51,7 +51,8 @@ To override values in a chart, use either the '--values' flag and pass in a file
 or use the '--set' flag and pass configuration from the command line, to force
 a string value use '--set-string'. You can use '--set-file' to set individual
 values from a file when the value itself is too long for the command line
-or is dynamically generated.
+or is dynamically generated. You can also use '--set-json' to set json values
+(scalars/objects/arrays) from the command line.
 
     $ helm install -f myvalues.yaml myredis ./redis
 
@@ -67,6 +68,11 @@ or
 
     $ helm install --set-file my_script=dothings.sh myredis ./redis
 
+or
+
+    $ helm install --set-json 'master.sidecars=[{"name":"sidecar","image":"myImage","imagePullPolicy":"Always","ports":[{"name":"portname","containerPort":1234}]}]' myredis ./redis
+
+
 You can specify the '--values'/'-f' flag multiple times. The priority will be given to the
 last (right-most) file specified. For example, if both myvalues.yaml and override.yaml
 contained a key called 'Test', the value set in override.yaml would take precedence:
@@ -79,6 +85,13 @@ set for a key called 'foo', the 'newbar' value would take precedence:
 
     $ helm install --set foo=bar --set foo=newbar  myredis ./redis
 
+Similarly, in the following example 'foo' is set to '["four"]': 
+
+    $ helm install --set-json='foo=["one", "two", "three"]' --set-json='foo=["four"]' myredis ./redis
+
+And in the following example, 'foo' is set to '{"key1":"value1","key2":"bar"}':
+
+    $ helm install --set-json='foo={"key1":"value1","key2":"value2"}' --set-json='foo.key2="bar"' myredis ./redis
 
 To check the generated manifests of a release without installing the chart,
 the '--debug' and '--dry-run' flags can be combined.

cmd/helm/upgrade.go

@@ -51,7 +51,8 @@ To override values in a chart, use either the '--values' flag and pass in a file
 or use the '--set' flag and pass configuration from the command line, to force string
 values, use '--set-string'. You can use '--set-file' to set individual
 values from a file when the value itself is too long for the command line
-or is dynamically generated.
+or is dynamically generated. You can also use '--set-json' to set json values
+(scalars/objects/arrays) from the command line.
 
 You can specify the '--values'/'-f' flag multiple times. The priority will be given to the
 last (right-most) file specified. For example, if both myvalues.yaml and override.yaml

internal/test/test.go

@@ -88,7 +88,7 @@ func compare(actual []byte, filename string) error {
 	}
 	expected = normalize(expected)
 	if !bytes.Equal(expected, actual) {
-		return errors.Errorf("does not match golden file %s\n\nWANT:\n'%s'\n\nGOT:\n'%s'\n", filename, expected, actual)
+		return errors.Errorf("does not match golden file %s\n\nWANT:\n'%s'\n\nGOT:\n'%s'", filename, expected, actual)
 	}
 	return nil
 }

pkg/cli/values/options.go

@@ -34,6 +34,7 @@ type Options struct {
 	StringValues []string
 	Values       []string
 	FileValues   []string
+	JSONValues   []string
 }
 
 // MergeValues merges values from files specified via -f/--values and directly
@@ -57,6 +58,13 @@ func (opts *Options) MergeValues(p getter.Providers) (map[string]interface{}, er
 		base = mergeMaps(base, currentMap)
 	}
 
+	// User specified a value via --set-json
+	for _, value := range opts.JSONValues {
+		if err := strvals.ParseJSON(value, base); err != nil {
+			return nil, errors.Errorf("failed parsing --set-json data %s", value)
+		}
+	}
+
 	// User specified a value via --set
 	for _, value := range opts.Values {
 		if err := strvals.ParseInto(value, base); err != nil {

pkg/strvals/parser.go

@@ -17,10 +17,13 @@ package strvals
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"strconv"
 	"strings"
+	"unicode"
 
 	"github.com/pkg/errors"
 	"sigs.k8s.io/yaml"
@@ -94,6 +97,18 @@ func ParseIntoString(s string, dest map[string]interface{}) error {
 	return t.parse()
 }
 
+// ParseJSON parses a string with format key1=val1, key2=val2, ...
+// where values are json strings (null, or scalars, or arrays, or objects).
+// An empty val is treated as null.
+//
+// If a key exists in dest, the new value overwrites the dest version.
+//
+func ParseJSON(s string, dest map[string]interface{}) error {
+	scanner := bytes.NewBufferString(s)
+	t := newJSONParser(scanner, dest)
+	return t.parse()
+}
+
 // ParseIntoFile parses a filevals line and merges the result into dest.
 //
 // This method always returns a string as the value.
@@ -113,9 +128,10 @@ type RunesValueReader func([]rune) (interface{}, error)
 // where sc is the source of the original data being parsed
 // where data is the final parsed data from the parses with correct types
 type parser struct {
-	sc     *bytes.Buffer
-	data   map[string]interface{}
-	reader RunesValueReader
+	sc        *bytes.Buffer
+	data      map[string]interface{}
+	reader    RunesValueReader
+	isjsonval bool
 }
 
 func newParser(sc *bytes.Buffer, data map[string]interface{}, stringBool bool) *parser {
@@ -125,6 +141,10 @@ func newParser(sc *bytes.Buffer, data map[string]interface{}, stringBool bool) *
 	return &parser{sc: sc, data: data, reader: stringConverter}
 }
 
+func newJSONParser(sc *bytes.Buffer, data map[string]interface{}) *parser {
+	return &parser{sc: sc, data: data, reader: nil, isjsonval: true}
+}
+
 func newFileParser(sc *bytes.Buffer, data map[string]interface{}, reader RunesValueReader) *parser {
 	return &parser{sc: sc, data: data, reader: reader}
 }
@@ -184,6 +204,33 @@ func (t *parser) key(data map[string]interface{}) (reterr error) {
 			set(data, kk, list)
 			return err
 		case last == '=':
+			if t.isjsonval {
+				empval, err := t.emptyVal()
+				if err != nil {
+					return err
+				}
+				if empval {
+					set(data, string(k), nil)
+					return nil
+				}
+				// parse jsonvals by using Go’s JSON standard library
+				// Decode is preferred to Unmarshal in order to parse just the json parts of the list key1=jsonval1,key2=jsonval2,...
+				// Since Decode has its own buffer that consumes more characters (from underlying t.sc) than the ones actually decoded,
+				// we invoke Decode on a separate reader built with a copy of what is left in t.sc. After Decode is executed, we
+				// discard in t.sc the chars of the decoded json value (the number of those characters is returned by InputOffset).
+				var jsonval interface{}
+				dec := json.NewDecoder(strings.NewReader(t.sc.String()))
+				if err = dec.Decode(&jsonval); err != nil {
+					return err
+				}
+				set(data, string(k), jsonval)
+				if _, err = io.CopyN(ioutil.Discard, t.sc, dec.InputOffset()); err != nil {
+					return err
+				}
+				// skip possible blanks and comma
+				_, err = t.emptyVal()
+				return err
+			}
 			//End of key. Consume =, Get value.
 			// FIXME: Get value list first
 			vl, e := t.valList()
@@ -205,7 +252,6 @@ func (t *parser) key(data map[string]interface{}) (reterr error) {
 			default:
 				return e
 			}
-
 		case last == ',':
 			// No value given. Set the value to empty string. Return error.
 			set(data, string(k), "")
@@ -280,6 +326,34 @@ func (t *parser) listItem(list []interface{}, i int) ([]interface{}, error) {
 	case err != nil:
 		return list, err
 	case last == '=':
+		if t.isjsonval {
+			empval, err := t.emptyVal()
+			if err != nil {
+				return list, err
+			}
+			if empval {
+				return setIndex(list, i, nil)
+			}
+			// parse jsonvals by using Go’s JSON standard library
+			// Decode is preferred to Unmarshal in order to parse just the json parts of the list key1=jsonval1,key2=jsonval2,...
+			// Since Decode has its own buffer that consumes more characters (from underlying t.sc) than the ones actually decoded,
+			// we invoke Decode on a separate reader built with a copy of what is left in t.sc. After Decode is executed, we
+			// discard in t.sc the chars of the decoded json value (the number of those characters is returned by InputOffset).
+			var jsonval interface{}
+			dec := json.NewDecoder(strings.NewReader(t.sc.String()))
+			if err = dec.Decode(&jsonval); err != nil {
+				return list, err
+			}
+			if list, err = setIndex(list, i, jsonval); err != nil {
+				return list, err
+			}
+			if _, err = io.CopyN(ioutil.Discard, t.sc, dec.InputOffset()); err != nil {
+				return list, err
+			}
+			// skip possible blanks and comma
+			_, err = t.emptyVal()
+			return list, err
+		}
 		vl, e := t.valList()
 		switch e {
 		case nil:
@@ -343,6 +417,28 @@ func (t *parser) listItem(list []interface{}, i int) ([]interface{}, error) {
 	}
 }
 
+// check for an empty value
+// read and consume optional spaces until comma or EOF (empty val) or any other char (not empty val)
+// comma and spaces are consumed, while any other char is not cosumed
+func (t *parser) emptyVal() (bool, error) {
+	for {
+		r, _, e := t.sc.ReadRune()
+		if e == io.EOF {
+			return true, nil
+		}
+		if e != nil {
+			return false, e
+		}
+		if r == ',' {
+			return true, nil
+		}
+		if !unicode.IsSpace(r) {
+			t.sc.UnreadRune()
+			return false, nil
+		}
+	}
+}
+
 func (t *parser) val() ([]rune, error) {
 	stop := runeSet([]rune{','})
 	v, _, err := runesUntil(t.sc, stop)

pkg/strvals/parser_test.go

@@ -567,6 +567,107 @@ func TestParseIntoString(t *testing.T) {
 	}
 }
 
+func TestParseJSON(t *testing.T) {
+	tests := []struct {
+		input  string
+		got    map[string]interface{}
+		expect map[string]interface{}
+		err    bool
+	}{
+		{ // set json scalars values, and replace one existing key
+			input: "outer.inner1=\"1\",outer.inner3=3,outer.inner4=true,outer.inner5=\"true\"",
+			got: map[string]interface{}{
+				"outer": map[string]interface{}{
+					"inner1": "overwrite",
+					"inner2": "value2",
+				},
+			},
+			expect: map[string]interface{}{
+				"outer": map[string]interface{}{
+					"inner1": "1",
+					"inner2": "value2",
+					"inner3": 3,
+					"inner4": true,
+					"inner5": "true",
+				},
+			},
+			err: false,
+		},
+		{ // set json objects and arrays, and replace one existing key
+			input: "outer.inner1={\"a\":\"1\",\"b\":2,\"c\":[1,2,3]},outer.inner3=[\"new value 1\",\"new value 2\"],outer.inner4={\"aa\":\"1\",\"bb\":2,\"cc\":[1,2,3]},outer.inner5=[{\"A\":\"1\",\"B\":2,\"C\":[1,2,3]}]",
+			got: map[string]interface{}{
+				"outer": map[string]interface{}{
+					"inner1": map[string]interface{}{
+						"x": "overwrite",
+					},
+					"inner2": "value2",
+					"inner3": []interface{}{
+						"overwrite",
+					},
+				},
+			},
+			expect: map[string]interface{}{
+				"outer": map[string]interface{}{
+					"inner1": map[string]interface{}{"a": "1", "b": 2, "c": []interface{}{1, 2, 3}},
+					"inner2": "value2",
+					"inner3": []interface{}{"new value 1", "new value 2"},
+					"inner4": map[string]interface{}{"aa": "1", "bb": 2, "cc": []interface{}{1, 2, 3}},
+					"inner5": []interface{}{map[string]interface{}{"A": "1", "B": 2, "C": []interface{}{1, 2, 3}}},
+				},
+			},
+			err: false,
+		},
+		{ // null assigment, and no value assigned (equivalent to null)
+			input: "outer.inner1=,outer.inner3={\"aa\":\"1\",\"bb\":2,\"cc\":[1,2,3]},outer.inner3.cc[1]=null",
+			got: map[string]interface{}{
+				"outer": map[string]interface{}{
+					"inner1": map[string]interface{}{
+						"x": "overwrite",
+					},
+					"inner2": "value2",
+				},
+			},
+			expect: map[string]interface{}{
+				"outer": map[string]interface{}{
+					"inner1": nil,
+					"inner2": "value2",
+					"inner3": map[string]interface{}{"aa": "1", "bb": 2, "cc": []interface{}{1, nil, 3}},
+				},
+			},
+			err: false,
+		},
+		{ // syntax error
+			input:  "outer.inner1={\"a\":\"1\",\"b\":2,\"c\":[1,2,3]},outer.inner3=[\"new value 1\",\"new value 2\"],outer.inner4={\"aa\":\"1\",\"bb\":2,\"cc\":[1,2,3]},outer.inner5={\"A\":\"1\",\"B\":2,\"C\":[1,2,3]}]",
+			got:    nil,
+			expect: nil,
+			err:    true,
+		},
+	}
+	for _, tt := range tests {
+		if err := ParseJSON(tt.input, tt.got); err != nil {
+			if tt.err {
+				continue
+			}
+			t.Fatalf("%s: %s", tt.input, err)
+		}
+		if tt.err {
+			t.Fatalf("%s: Expected error. Got nil", tt.input)
+		}
+		y1, err := yaml.Marshal(tt.expect)
+		if err != nil {
+			t.Fatalf("Error serializing expected value: %s", err)
+		}
+		y2, err := yaml.Marshal(tt.got)
+		if err != nil {
+			t.Fatalf("Error serializing parsed value: %s", err)
+		}
+
+		if string(y1) != string(y2) {
+			t.Errorf("%s: Expected:\n%s\nGot:\n%s", tt.input, y1, y2)
+		}
+	}
+}
+
 func TestParseFile(t *testing.T) {
 	input := "name1=path1"
 	expect := map[string]interface{}{