flagsmith panics with wrong Base URL set

[mvrhov]

There is a panic inside flagsmith when used with wrong URL set and via open-feature.

panic({0x8dcc00?, 0xb922d0?})
        /usr/local/go/src/runtime/panic.go:920 +0x290
github.com/Flagsmith/flagsmith-go-client/v3/flagengine.GetIdentitySegments(0xc000066360, 0xc0002058c8, {0x0, 0x0, 0x0})
        /home/m/go/pkg/mod/github.com/!flagsmith/flagsmith-go-client/v3@v3.1.0/flagengine/engine.go:77 +0x71
github.com/Flagsmith/flagsmith-go-client/v3/flagengine.getIdentityFeatureStatesMap(0xc000066360, 0xc0002058c8, {0x0, 0x0, 0x0})
        /home/m/go/pkg/mod/github.com/!flagsmith/flagsmith-go-client/v3@v3.1.0/flagengine/engine.go:96 +0x172
github.com/Flagsmith/flagsmith-go-client/v3/flagengine.GetIdentityFeatureStates(0xc000066360, 0xc0002058c8, {0x0, 0x0, 0x0})
        /home/m/go/pkg/mod/github.com/!flagsmith/flagsmith-go-client/v3@v3.1.0/flagengine/engine.go:41 +0x7e
github.com/Flagsmith/flagsmith-go-client/v3.(*Client).getIdentityFlagsFromEnvironment(0xc000100be0, {0x93a4cb, 0x10}, {0x0, 0x0, 0x0})
        /home/m/go/pkg/mod/github.com/!flagsmith/flagsmith-go-client/v3@v3.1.0/client.go:189 +0x1b3
github.com/Flagsmith/flagsmith-go-client/v3.(*Client).GetIdentityFlags(0xc000100be0, {0x9a5b00, 0xbcf3c0}, {0x93a4cb, 0x10}, {0x0, 0x0, 0x0})
        /home/m/go/pkg/mod/github.com/!flagsmith/flagsmith-go-client/v3@v3.1.0/client.go:98 +0xec
github.com/open-feature/go-sdk-contrib/providers/flagsmith/pkg.(*Provider).resolveFlag(0xc000016ef0, {0x9a5b00, 0xbcf3c0}, {0x93b2b4, 0x12}, {0x8c77a0, 0xb70b40}, 0xc0001a03c0)
        /home/m/go/pkg/mod/github.com/open-feature/go-sdk-contrib/providers/flagsmith@v0.1.4/pkg/provider.go:76 +0xd2d
github.com/open-feature/go-sdk-contrib/providers/flagsmith/pkg.(*Provider).BooleanEvaluation(0xc000016ef0, {0x9a5b00, 0xbcf3c0}, {0x93b2b4, 0x12}, 0x0, 0xc0001a03c0)
        /home/m/go/pkg/mod/github.com/open-feature/go-sdk-contrib/providers/flagsmith@v0.1.4/pkg/provider.go:134 +0xd3
github.com/open-feature/go-sdk/pkg/openfeature.(*Client).evaluate(0xc0000662a0, {0x9a5b00, 0xbcf3c0}, {0x93b2b4, 0x12}, 0x0, {0x8c77a0, 0xb70b40}, {{0x93a4cb, 0x10}, ...}, ...)
        /home/m/go/pkg/mod/github.com/open-feature/go-sdk@v1.5.1/pkg/openfeature/client.go:714 +0x17c4
github.com/open-feature/go-sdk/pkg/openfeature.(*Client).BooleanValue(0xc0000662a0, {0x9a5b00, 0xbcf3c0}, {0x93b2b4, 0x12}, 0x0, {{0x93a4cb, 0x10}, 0xc0001a0300}, {0x0, ...})
        /home/m/go/pkg/mod/github.com/open-feature/go-sdk@v1.5.1/pkg/openfeature/client.go:303 +0x332
main.helloServer({0x9a53c0, 0xc0001fc000}, 0xc0001f6000)
        /home/m/ff/flagsmith/main.go:54 +0x39a
net/http.HandlerFunc.ServeHTTP(0x97e160, {0x9a53c0, 0xc0001fc000}, 0xc0001f6000)

This is the main.go

package main

import (
	"context"
	"github.com/Flagsmith/flagsmith-go-client/v3"
	openFlagsmith "github.com/open-feature/go-sdk-contrib/providers/flagsmith/pkg"
	"github.com/open-feature/go-sdk/pkg/openfeature"
	"io"
	"log"
	"net/http"
	"time"
)

var feature *openfeature.Client
var fc *flagsmith.Client

func init() {
	ctx := context.Background()
	// Initialize the flagsmith client
	client := flagsmith.NewClient(
		"ser.redactedredacted",
		flagsmith.WithLocalEvaluation(context.Background()),
		flagsmith.WithBaseURL("http://localhost:8000/"),
		//flagsmith.WithBaseURL("http://localhost:8000/api/v1/"),
		flagsmith.WithEnvironmentRefreshInterval(30*time.Second),
		flagsmith.WithAnalytics(ctx),
		flagsmith.WithRetries(3, 5*time.Second),
		flagsmith.WithDefaultHandler(func(s string) (flagsmith.Flag, error) {
			return flagsmith.Flag{Enabled: false}, nil
		}),
	)

	// Initialize the flagsmith provider
	provider := openFlagsmith.NewProvider(client, openFlagsmith.WithUsingBooleanConfigValue())

	openfeature.SetProvider(provider)

	// Create open feature client
	feature = openfeature.NewClient("prod")
	fc = client
}

func helloServer(w http.ResponseWriter, req *http.Request) {
	f, err := fc.GetEnvironmentFlags(context.Background())
	_, err = f.IsFeatureEnabled("bool_feature")
	_, err = f.IsFeatureEnabled("engine_status")
	_ = err

	evalCtx := openfeature.NewEvaluationContext(
		"openfeature_user",
		map[string]interface{}{},
	)

	if enabled, err := feature.BooleanValue(context.Background(), "engine_status", false, evalCtx); enabled && err == nil {
		io.WriteString(w, "Feature enabled\n")
	} else {
		io.WriteString(w, "hello, world!\n")
	}
}

func main() {
	http.HandleFunc("/", helloServer)
	log.Fatal(http.ListenAndServe(":8080", nil))
}

[gagantrivedi]

@mvrhov Thanks - I will take a look

[gagantrivedi]

@mvrhov I'm unable to replicate the error you're encountering. Could you please confirm that the code you've provided is accurate and corresponds to the error you're experiencing?

[gagantrivedi]

I am going to close this for now. Feel free to reopen with more information if you are still facing this

[mvrhov]

It seems that the above example doesn't reproduce it each time. However I've jut got this in one production server where we have disabled flagsmith . (By not setting up the URL)

[mvrhov]

Ah. I have figured it out. flagsmith.WithBaseURL("http://localhost:8000/"). You MUST have server responding on that URL. But not flagsmith itself. And it will crash with above panic

[mvrhov]

Can you please release/tag 3.1.1 now that both #100 and #101 are merged. Thanks.

[gagantrivedi]

Can you please release/tag 3.1.1 now that both #100 and #101 are merged. Thanks.

Released: https://github.com/Flagsmith/flagsmith-go-client/releases/tag/v3.1.1