From bb2d86eb397840257340ed79433bc2abe6a1f3b5 Mon Sep 17 00:00:00 2001
From: Jeff Mitchell <jeffrey.mitchell@gmail.com>
Date: Tue, 16 Mar 2021 11:19:10 -0400
Subject: [PATCH] Add ability to generate pseudo-random IDs (#984)

---
 internal/db/id.go      | 24 +++++++++++++++-----
 internal/db/id_test.go | 50 ++++++++++++++++++++++++++++++++++++++++++
 internal/db/option.go  | 10 +++++++++
 3 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/internal/db/id.go b/internal/db/id.go
index 9a58054c23..2c40e20f82 100644
--- a/internal/db/id.go
+++ b/internal/db/id.go
@@ -1,27 +1,39 @@
 package db
 
 import (
+	"bytes"
 	"fmt"
+	"strings"
 
 	"github.com/hashicorp/boundary/internal/errors"
 	"github.com/hashicorp/vault/sdk/helper/base62"
+	"golang.org/x/crypto/blake2b"
 )
 
-func NewPrivateId(prefix string) (string, error) {
-	return newId(prefix)
+func NewPrivateId(prefix string, opt ...Option) (string, error) {
+	return newId(prefix, opt...)
 }
 
 // NewPublicId creates a new public id with the prefix
-func NewPublicId(prefix string) (string, error) {
-	return newId(prefix)
+func NewPublicId(prefix string, opt ...Option) (string, error) {
+	return newId(prefix, opt...)
 }
 
-func newId(prefix string) (string, error) {
+func newId(prefix string, opt ...Option) (string, error) {
 	const op = "db.newId"
 	if prefix == "" {
 		return "", errors.New(errors.InvalidParameter, op, "missing prefix")
 	}
-	publicId, err := base62.Random(10)
+	var publicId string
+	var err error
+	opts := GetOpts(opt...)
+	if len(opts.withPrngValues) > 0 {
+		sum := blake2b.Sum256([]byte(strings.Join(opts.withPrngValues, "|")))
+		reader := bytes.NewReader(sum[0:])
+		publicId, err = base62.RandomWithReader(10, reader)
+	} else {
+		publicId, err = base62.Random(10)
+	}
 	if err != nil {
 		return "", errors.Wrap(err, op, errors.WithMsg("unable to generate id"), errors.WithCode(errors.Io))
 	}
diff --git a/internal/db/id_test.go b/internal/db/id_test.go
index e26a4c1593..776653afb8 100644
--- a/internal/db/id_test.go
+++ b/internal/db/id_test.go
@@ -93,3 +93,53 @@ func TestNewPrivateId(t *testing.T) {
 		})
 	}
 }
+
+func TestPseudoRandomId(t *testing.T) {
+	type args struct {
+		prngValues []string
+	}
+	tests := []struct {
+		name       string
+		args       args
+		sameAsPrev bool
+	}{
+		{
+			name: "valid first",
+			args: args{},
+		},
+		{
+			name: "valid second",
+			args: args{},
+		},
+		{
+			name: "first prng",
+			args: args{prngValues: []string{"foo", "bar"}},
+		},
+		{
+			name:       "first prng verify",
+			args:       args{prngValues: []string{"foo", "bar"}},
+			sameAsPrev: true,
+		},
+		{
+			name: "second prng",
+			args: args{prngValues: []string{"bar", "foo"}},
+		},
+		{
+			name:       "second prng verify",
+			args:       args{prngValues: []string{"bar", "foo"}},
+			sameAsPrev: true,
+		},
+	}
+	var prevTestValue string
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert, require := assert.New(t), require.New(t)
+			got, err := NewPublicId("id", WithPrngValues(tt.args.prngValues))
+			require.NoError(err)
+			if tt.sameAsPrev {
+				assert.Equal(prevTestValue, got)
+			}
+			prevTestValue = got
+		})
+	}
+}
diff --git a/internal/db/option.go b/internal/db/option.go
index b55af90c24..1547bab9ae 100644
--- a/internal/db/option.go
+++ b/internal/db/option.go
@@ -40,6 +40,9 @@ type Options struct {
 	withWhereClause     string
 	withWhereClauseArgs []interface{}
 	withOrder           string
+
+	// withPrngValues is used to switch the ID generation to a pseudo-random mode
+	withPrngValues []string
 }
 
 type oplogOpts struct {
@@ -155,3 +158,10 @@ func WithOrder(withOrder string) Option {
 		o.withOrder = withOrder
 	}
 }
+
+// WithPrngValues provides an option to provide values to seed an PRNG when generating IDs
+func WithPrngValues(withPrngValues []string) Option {
+	return func(o *Options) {
+		o.withPrngValues = withPrngValues
+	}
+}