Repository: redis/go-redis

Issue:
Feature request: Add ParseFailoverURL
Please add support for `ParseFailoverURL` for `FailoverOptions`, analogue of `ParseURL`, `ParseClusterURL` 
Also maybe some constructor that create redis.UniversalClient from url.

Hints from issue comments:
@ndyakov: Hello @khasanovbi , I am marking this as good first issue and if someone would like to work on it I will provide assistance. @deidaraiorek: @ndyakov hi i would love to work on this@ndyakov: @deidaraiorek feel free to take a shot at it. You can start from the https://github.com/redis/go-redis/blob/master/CONTRIBUTING.md and if you find anything missing from the documentation feel free to ask me questions (you can find me on the discord https://discord.gg/U3TkxJfJRk .

Solution patch:
diff --git a/sentinel.go b/sentinel.go
index cfc848c..314bde1 100644
--- a/sentinel.go
+++ b/sentinel.go
@@ -6,6 +6,8 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"net/url"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -220,6 +222,146 @@ func (opt *FailoverOptions) clusterOptions() *ClusterOptions {
 	}
 }
 
+// ParseFailoverURL parses a URL into FailoverOptions that can be used to connect to Redis.
+// The URL must be in the form:
+//
+//	redis://<user>:<password>@<host>:<port>/<db_number>
+//	or
+//	rediss://<user>:<password>@<host>:<port>/<db_number>
+//
+// To add additional addresses, specify the query parameter, "addr" one or more times. e.g:
+//
+//	redis://<user>:<password>@<host>:<port>/<db_number>?addr=<host2>:<port2>&addr=<host3>:<port3>
+//	or
+//	rediss://<user>:<password>@<host>:<port>/<db_number>?addr=<host2>:<port2>&addr=<host3>:<port3>
+//
+// Most Option fields can be set using query parameters, with the following restrictions:
+//   - field names are mapped using snake-case conversion: to set MaxRetries, use max_retries
+//   - only scalar type fields are supported (bool, int, time.Duration)
+//   - for time.Duration fields, values must be a valid input for time.ParseDuration();
+//     additionally a plain integer as value (i.e. without unit) is interpreted as seconds
+//   - to disable a duration field, use value less than or equal to 0; to use the default
+//     value, leave the value blank or remove the parameter
+//   - only the last value is interpreted if a parameter is given multiple times
+//   - fields "network", "addr", "sentinel_username" and "sentinel_password" can only be set using other
+//     URL attributes (scheme, host, userinfo, resp.), query parameters using these
+//     names will be treated as unknown parameters
+//   - unknown parameter names will result in an error
+//
+// Example:
+//
+//	redis://user:password@localhost:6789?master_name=mymaster&dial_timeout=3&read_timeout=6s&addr=localhost:6790&addr=localhost:6791
+//	is equivalent to:
+//	&FailoverOptions{
+//		MasterName:  "mymaster",
+//		Addr:        ["localhost:6789", "localhost:6790", "localhost:6791"]
+//		DialTimeout: 3 * time.Second, // no time unit = seconds
+//		ReadTimeout: 6 * time.Second,
+//	}
+func ParseFailoverURL(redisURL string) (*FailoverOptions, error) {
+	u, err := url.Parse(redisURL)
+	if err != nil {
+		return nil, err
+	}
+	return setupFailoverConn(u)
+}
+
+func setupFailoverConn(u *url.URL) (*FailoverOptions, error) {
+	o := &FailoverOptions{}
+
+	o.SentinelUsername, o.SentinelPassword = getUserPassword(u)
+
+	h, p := getHostPortWithDefaults(u)
+	o.SentinelAddrs = append(o.SentinelAddrs, net.JoinHostPort(h, p))
+
+	switch u.Scheme {
+	case "rediss":
+		o.TLSConfig = &tls.Config{ServerName: h, MinVersion: tls.VersionTLS12}
+	case "redis":
+		o.TLSConfig = nil
+	default:
+		return nil, fmt.Errorf("redis: invalid URL scheme: %s", u.Scheme)
+	}
+
+	f := strings.FieldsFunc(u.Path, func(r rune) bool {
+		return r == '/'
+	})
+	switch len(f) {
+	case 0:
+		o.DB = 0
+	case 1:
+		var err error
+		if o.DB, err = strconv.Atoi(f[0]); err != nil {
+			return nil, fmt.Errorf("redis: invalid database number: %q", f[0])
+		}
+	default:
+		return nil, fmt.Errorf("redis: invalid URL path: %s", u.Path)
+	}
+
+	return setupFailoverConnParams(u, o)
+}
+
+func setupFailoverConnParams(u *url.URL, o *FailoverOptions) (*FailoverOptions, error) {
+	q := queryOptions{q: u.Query()}
+
+	o.MasterName = q.string("master_name")
+	o.ClientName = q.string("client_name")
+	o.RouteByLatency = q.bool("route_by_latency")
+	o.RouteRandomly = q.bool("route_randomly")
+	o.ReplicaOnly = q.bool("replica_only")
+	o.UseDisconnectedReplicas = q.bool("use_disconnected_replicas")
+	o.Protocol = q.int("protocol")
+	o.Username = q.string("username")
+	o.Password = q.string("password")
+	o.MaxRetries = q.int("max_retries")
+	o.MinRetryBackoff = q.duration("min_retry_backoff")
+	o.MaxRetryBackoff = q.duration("max_retry_backoff")
+	o.DialTimeout = q.duration("dial_timeout")
+	o.ReadTimeout = q.duration("read_timeout")
+	o.WriteTimeout = q.duration("write_timeout")
+	o.ContextTimeoutEnabled = q.bool("context_timeout_enabled")
+	o.PoolFIFO = q.bool("pool_fifo")
+	o.PoolSize = q.int("pool_size")
+	o.MinIdleConns = q.int("min_idle_conns")
+	o.MaxIdleConns = q.int("max_idle_conns")
+	o.MaxActiveConns = q.int("max_active_conns")
+	o.ConnMaxLifetime = q.duration("conn_max_lifetime")
+	o.ConnMaxIdleTime = q.duration("conn_max_idle_time")
+	o.PoolTimeout = q.duration("pool_timeout")
+	o.DisableIdentity = q.bool("disableIdentity")
+	o.IdentitySuffix = q.string("identitySuffix")
+	o.UnstableResp3 = q.bool("unstable_resp3")
+
+	if q.err != nil {
+		return nil, q.err
+	}
+
+	if tmp := q.string("db"); tmp != "" {
+		db, err := strconv.Atoi(tmp)
+		if err != nil {
+			return nil, fmt.Errorf("redis: invalid database number: %w", err)
+		}
+		o.DB = db
+	}
+
+	addrs := q.strings("addr")
+	for _, addr := range addrs {
+		h, p, err := net.SplitHostPort(addr)
+		if err != nil || h == "" || p == "" {
+			return nil, fmt.Errorf("redis: unable to parse addr param: %s", addr)
+		}
+
+		o.SentinelAddrs = append(o.SentinelAddrs, net.JoinHostPort(h, p))
+	}
+
+	// any parameters left?
+	if r := q.remaining(); len(r) > 0 {
+		return nil, fmt.Errorf("redis: unexpected option: %s", strings.Join(r, ", "))
+	}
+
+	return o, nil
+}
+
 // NewFailoverClient returns a Redis client that uses Redis Sentinel
 // for automatic failover. It's safe for concurrent use by multiple
 // goroutines.



Test patch:
diff --git a/example_test.go b/example_test.go
index 28d14b6..c20e839 100644
--- a/example_test.go
+++ b/example_test.go
@@ -359,7 +359,7 @@ func ExampleMapStringStringCmd_Scan() {
 	// Get the map. The same approach works for HmGet().
 	res := rdb.HGetAll(ctx, "map")
 	if res.Err() != nil {
-		panic(err)
+		panic(res.Err())
 	}
 
 	type data struct {
@@ -392,7 +392,7 @@ func ExampleSliceCmd_Scan() {
 
 	res := rdb.MGet(ctx, "name", "count", "empty", "correct")
 	if res.Err() != nil {
-		panic(err)
+		panic(res.Err())
 	}
 
 	type data struct {
diff --git a/sentinel_test.go b/sentinel_test.go
index 2d481d5..436895f 100644
--- a/sentinel_test.go
+++ b/sentinel_test.go
@@ -2,7 +2,11 @@ package redis_test
 
 import (
 	"context"
+	"crypto/tls"
+	"errors"
 	"net"
+	"sort"
+	"testing"
 	"time"
 
 	. "github.com/bsm/ginkgo/v2"
@@ -405,3 +409,266 @@ var _ = Describe("SentinelAclAuth", func() {
 		Expect(val).To(Equal("acl-auth"))
 	})
 })
+
+func TestParseFailoverURL(t *testing.T) {
+	cases := []struct {
+		url string
+		o   *redis.FailoverOptions
+		err error
+	}{
+		{
+			url: "redis://localhost:6379?master_name=test",
+			o:   &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6379"}, MasterName: "test"},
+		},
+		{
+			url: "redis://localhost:6379/5?master_name=test",
+			o:   &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6379"}, MasterName: "test", DB: 5},
+		},
+		{
+			url: "rediss://localhost:6379/5?master_name=test",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6379"}, MasterName: "test", DB: 5,
+				TLSConfig: &tls.Config{
+					ServerName: "localhost",
+				}},
+		},
+		{
+			url: "redis://localhost:6379/5?master_name=test&db=2",
+			o:   &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6379"}, MasterName: "test", DB: 2},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&addr=localhost:6381",
+			o:   &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379", "localhost:6381"}, DB: 5},
+		},
+		{
+			url: "redis://foo:bar@localhost:6379/5?addr=localhost:6380",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				SentinelUsername: "foo", SentinelPassword: "bar", DB: 5},
+		},
+		{
+			url: "redis://:bar@localhost:6379/5?addr=localhost:6380",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				SentinelUsername: "", SentinelPassword: "bar", DB: 5},
+		},
+		{
+			url: "redis://foo@localhost:6379/5?addr=localhost:6380",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				SentinelUsername: "foo", SentinelPassword: "", DB: 5},
+		},
+		{
+			url: "redis://foo:bar@localhost:6379/5?addr=localhost:6380&dial_timeout=3",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				SentinelUsername: "foo", SentinelPassword: "bar", DB: 5, DialTimeout: 3 * time.Second},
+		},
+		{
+			url: "redis://foo:bar@localhost:6379/5?addr=localhost:6380&dial_timeout=3s",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				SentinelUsername: "foo", SentinelPassword: "bar", DB: 5, DialTimeout: 3 * time.Second},
+		},
+		{
+			url: "redis://foo:bar@localhost:6379/5?addr=localhost:6380&dial_timeout=3ms",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				SentinelUsername: "foo", SentinelPassword: "bar", DB: 5, DialTimeout: 3 * time.Millisecond},
+		},
+		{
+			url: "redis://foo:bar@localhost:6379/5?addr=localhost:6380&dial_timeout=3&pool_fifo=true",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				SentinelUsername: "foo", SentinelPassword: "bar", DB: 5, DialTimeout: 3 * time.Second, PoolFIFO: true},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout=3&pool_fifo=false",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: 3 * time.Second, PoolFIFO: false},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout=3&pool_fifo",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: 3 * time.Second, PoolFIFO: false},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: 0},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout=0",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: -1},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout=-1",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: -1},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout=-2",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: -1},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout=",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: 0},
+		},
+		{
+			url: "redis://localhost:6379/5?addr=localhost:6380&dial_timeout=0&abc=5",
+			o: &redis.FailoverOptions{SentinelAddrs: []string{"localhost:6380", "localhost:6379"},
+				DB: 5, DialTimeout: -1},
+			err: errors.New("redis: unexpected option: abc"),
+		},
+		{
+			url: "http://google.com",
+			err: errors.New("redis: invalid URL scheme: http"),
+		},
+		{
+			url: "redis://localhost/1/2/3/4",
+			err: errors.New("redis: invalid URL path: /1/2/3/4"),
+		},
+		{
+			url: "12345",
+			err: errors.New("redis: invalid URL scheme: "),
+		},
+		{
+			url: "redis://localhost/database",
+			err: errors.New(`redis: invalid database number: "database"`),
+		},
+	}
+
+	for i := range cases {
+		tc := cases[i]
+		t.Run(tc.url, func(t *testing.T) {
+			t.Parallel()
+
+			actual, err := redis.ParseFailoverURL(tc.url)
+			if tc.err == nil && err != nil {
+				t.Fatalf("unexpected error: %q", err)
+				return
+			}
+			if tc.err != nil && err == nil {
+				t.Fatalf("got nil, expected %q", tc.err)
+				return
+			}
+			if tc.err != nil && err != nil {
+				if tc.err.Error() != err.Error() {
+					t.Fatalf("got %q, expected %q", err, tc.err)
+				}
+				return
+			}
+			compareFailoverOptions(t, actual, tc.o)
+		})
+	}
+}
+
+func compareFailoverOptions(t *testing.T, a, e *redis.FailoverOptions) {
+	if a.MasterName != e.MasterName {
+		t.Errorf("MasterName got %q, want %q", a.MasterName, e.MasterName)
+	}
+	compareSlices(t, a.SentinelAddrs, e.SentinelAddrs, "SentinelAddrs")
+	if a.ClientName != e.ClientName {
+		t.Errorf("ClientName got %q, want %q", a.ClientName, e.ClientName)
+	}
+	if a.SentinelUsername != e.SentinelUsername {
+		t.Errorf("SentinelUsername got %q, want %q", a.SentinelUsername, e.SentinelUsername)
+	}
+	if a.SentinelPassword != e.SentinelPassword {
+		t.Errorf("SentinelPassword got %q, want %q", a.SentinelPassword, e.SentinelPassword)
+	}
+	if a.RouteByLatency != e.RouteByLatency {
+		t.Errorf("RouteByLatency got %v, want %v", a.RouteByLatency, e.RouteByLatency)
+	}
+	if a.RouteRandomly != e.RouteRandomly {
+		t.Errorf("RouteRandomly got %v, want %v", a.RouteRandomly, e.RouteRandomly)
+	}
+	if a.ReplicaOnly != e.ReplicaOnly {
+		t.Errorf("ReplicaOnly got %v, want %v", a.ReplicaOnly, e.ReplicaOnly)
+	}
+	if a.UseDisconnectedReplicas != e.UseDisconnectedReplicas {
+		t.Errorf("UseDisconnectedReplicas got %v, want %v", a.UseDisconnectedReplicas, e.UseDisconnectedReplicas)
+	}
+	if a.Protocol != e.Protocol {
+		t.Errorf("Protocol got %v, want %v", a.Protocol, e.Protocol)
+	}
+	if a.Username != e.Username {
+		t.Errorf("Username got %q, want %q", a.Username, e.Username)
+	}
+	if a.Password != e.Password {
+		t.Errorf("Password got %q, want %q", a.Password, e.Password)
+	}
+	if a.DB != e.DB {
+		t.Errorf("DB got %v, want %v", a.DB, e.DB)
+	}
+	if a.MaxRetries != e.MaxRetries {
+		t.Errorf("MaxRetries got %v, want %v", a.MaxRetries, e.MaxRetries)
+	}
+	if a.MinRetryBackoff != e.MinRetryBackoff {
+		t.Errorf("MinRetryBackoff got %v, want %v", a.MinRetryBackoff, e.MinRetryBackoff)
+	}
+	if a.MaxRetryBackoff != e.MaxRetryBackoff {
+		t.Errorf("MaxRetryBackoff got %v, want %v", a.MaxRetryBackoff, e.MaxRetryBackoff)
+	}
+	if a.DialTimeout != e.DialTimeout {
+		t.Errorf("DialTimeout got %v, want %v", a.DialTimeout, e.DialTimeout)
+	}
+	if a.ReadTimeout != e.ReadTimeout {
+		t.Errorf("ReadTimeout got %v, want %v", a.ReadTimeout, e.ReadTimeout)
+	}
+	if a.WriteTimeout != e.WriteTimeout {
+		t.Errorf("WriteTimeout got %v, want %v", a.WriteTimeout, e.WriteTimeout)
+	}
+	if a.ContextTimeoutEnabled != e.ContextTimeoutEnabled {
+		t.Errorf("ContentTimeoutEnabled got %v, want %v", a.ContextTimeoutEnabled, e.ContextTimeoutEnabled)
+	}
+	if a.PoolFIFO != e.PoolFIFO {
+		t.Errorf("PoolFIFO got %v, want %v", a.PoolFIFO, e.PoolFIFO)
+	}
+	if a.PoolSize != e.PoolSize {
+		t.Errorf("PoolSize got %v, want %v", a.PoolSize, e.PoolSize)
+	}
+	if a.PoolTimeout != e.PoolTimeout {
+		t.Errorf("PoolTimeout got %v, want %v", a.PoolTimeout, e.PoolTimeout)
+	}
+	if a.MinIdleConns != e.MinIdleConns {
+		t.Errorf("MinIdleConns got %v, want %v", a.MinIdleConns, e.MinIdleConns)
+	}
+	if a.MaxIdleConns != e.MaxIdleConns {
+		t.Errorf("MaxIdleConns got %v, want %v", a.MaxIdleConns, e.MaxIdleConns)
+	}
+	if a.MaxActiveConns != e.MaxActiveConns {
+		t.Errorf("MaxActiveConns got %v, want %v", a.MaxActiveConns, e.MaxActiveConns)
+	}
+	if a.ConnMaxIdleTime != e.ConnMaxIdleTime {
+		t.Errorf("ConnMaxIdleTime got %v, want %v", a.ConnMaxIdleTime, e.ConnMaxIdleTime)
+	}
+	if a.ConnMaxLifetime != e.ConnMaxLifetime {
+		t.Errorf("ConnMaxLifeTime got %v, want %v", a.ConnMaxLifetime, e.ConnMaxLifetime)
+	}
+	if a.DisableIdentity != e.DisableIdentity {
+		t.Errorf("DisableIdentity got %v, want %v", a.DisableIdentity, e.DisableIdentity)
+	}
+	if a.IdentitySuffix != e.IdentitySuffix {
+		t.Errorf("IdentitySuffix got %v, want %v", a.IdentitySuffix, e.IdentitySuffix)
+	}
+	if a.UnstableResp3 != e.UnstableResp3 {
+		t.Errorf("UnstableResp3 got %v, want %v", a.UnstableResp3, e.UnstableResp3)
+	}
+	if (a.TLSConfig == nil && e.TLSConfig != nil) || (a.TLSConfig != nil && e.TLSConfig == nil) {
+		t.Errorf("TLSConfig error")
+	}
+	if a.TLSConfig != nil && e.TLSConfig != nil {
+		if a.TLSConfig.ServerName != e.TLSConfig.ServerName {
+			t.Errorf("TLSConfig.ServerName got %q, want %q", a.TLSConfig.ServerName, e.TLSConfig.ServerName)
+		}
+	}
+}
+
+func compareSlices(t *testing.T, a, b []string, name string) {
+	sort.Slice(a, func(i, j int) bool { return a[i] < a[j] })
+	sort.Slice(b, func(i, j int) bool { return b[i] < b[j] })
+	if len(a) != len(b) {
+		t.Errorf("%s got %q, want %q", name, a, b)
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			t.Errorf("%s got %q, want %q", name, a, b)
+		}
+	}
+}