fix: remove closeChannelWhenEmpty busy loop (#2594)

## Description
Addresses #2593 by
getting rid of the busy loop entirely. The loop was checking to make
sure all values from the channel were read before closing the channel.
When following logs, if a stream is cancelled before reading all logs in
the channel, it loops infinitely. This changes the consumer to loop
until it's read everything from the channel, even after its been closed.

 Also, adds a port for pprof to help with profiling in the future. 

## Is this change user facing?
YES 

## References 
#2593

cli/cli/commands/web/web.go

@@ -7,9 +7,9 @@ import (
 	"github.com/kurtosis-tech/kurtosis/cli/cli/command_framework/lowlevel/flags"
 	"github.com/kurtosis-tech/kurtosis/cli/cli/command_str_consts"
 	"github.com/kurtosis-tech/kurtosis/cli/cli/helpers/multi_os_command_executor"
-	"github.com/kurtosis-tech/kurtosis/container-engine-lib/lib/user_support_constants"
 	"github.com/kurtosis-tech/kurtosis/contexts-config-store/store"
 	"github.com/kurtosis-tech/stacktrace"
+	"github.com/sirupsen/logrus"
 )
 
 var WebCmd = &lowlevel.LowlevelKurtosisCommand{
@@ -35,9 +35,7 @@ func run(_ context.Context, _ *flags.ParsedFlags, _ *args.ParsedArgs) error {
 		return stacktrace.Propagate(err, "tried fetching the current Kurtosis context but failed, we can't switch clusters without this information. This is a bug in Kurtosis")
 	}
 	if store.IsRemote(currentKurtosisContext) {
-		if err := multi_os_command_executor.OpenFile(user_support_constants.KurtosisCloudLink); err != nil {
-			return stacktrace.Propagate(err, "An error occurred while opening the Kurtosis Cloud Web UI")
-		}
+		logrus.Warn("Kurtosis Cloud has been deprecated. Switch to a local kurtosis context to use the local Kurtosis web UI instead.")
 	}
 
 	if err := multi_os_command_executor.OpenFile(webUILink); err != nil {

container-engine-lib/lib/user_support_constants/user_support_constants.go

@@ -31,7 +31,6 @@ const (
 	FeedbackEmail                     = "feedback@" + OldDomain
 	FeedbackEmailLink                 = "mailto:" + FeedbackEmail
 	KurtosisTechTwitterProfileLink    = "https://twitter.com/KurtosisTech"
-	KurtosisCloudLink                 = "https://cloud." + Domain
 
 	//    If you add new URLs above, make sure to add them to the urlsToValidateInTest below!!!
 	// WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
@@ -56,6 +55,5 @@ var urlsToValidateInTest = []string{
 	KurtosisDiscordUrl,
 	KurtosisOnBoardCalendlyUrl,
 	HowImportWorksLink,
-	KurtosisCloudLink,
 	KurtosisTechTwitterProfileLink,
 }

engine/server/engine/centralized_logs/client_implementations/persistent_volume/persistent_volume_logs_database_client.go

@@ -90,14 +90,13 @@ func (client *persistentVolumeLogsDatabaseClient) StreamUserServiceLogs(
 
 	// this go routine handles the stream cancellation
 	go func() {
-		//wait for stream go routine to end
+		// wait for stream go routine to end
 		wgSenders.Wait()
 
-		// send all buffered log lines
+		// flush should send remainder of logs in the buffer to the channel to be read
 		logLineSender.Flush()
 
-		// wait until the channel has been fully read/empty before closing it
-		closeChannelWhenEmpty(logsByKurtosisUserServiceUuidChan)
+		close(logsByKurtosisUserServiceUuidChan)
 		close(streamErrChan)
 
 		//then cancel the context
@@ -174,12 +173,3 @@ func (client *persistentVolumeLogsDatabaseClient) streamServiceLogLines(
 		shouldReturnAllLogs,
 		numLogLines)
 }
-
-func closeChannelWhenEmpty(logsChan chan map[service.ServiceUUID][]logline.LogLine) {
-	for {
-		if len(logsChan) == 0 {
-			close(logsChan)
-			return
-		}
-	}
-}

engine/server/engine/centralized_logs/client_implementations/persistent_volume/persistent_volume_logs_database_client_test.go

@@ -721,11 +721,13 @@ func executeStreamCallAndGetReceivedServiceLogLines(
 		case <-time.Tick(testTimeOut):
 			return nil, stacktrace.NewError("Receiving stream logs in the test has reached the '%v' time out", testTimeOut)
 		case streamErr, isChanOpen := <-errChan:
-			if !isChanOpen {
+			if !isChanOpen && len(userServiceLogsByUuidChan) == 0 {
 				shouldReceiveStream = false
 				break
 			}
-			return nil, stacktrace.Propagate(streamErr, "Receiving streaming error.")
+			if isChanOpen && streamErr != nil {
+				return nil, stacktrace.Propagate(streamErr, "Receiving streaming error.")
+			}
 		case userServiceLogsByUuid, isChanOpen := <-userServiceLogsByUuidChan:
 			if !isChanOpen {
 				shouldReceiveStream = false

engine/server/engine/main.go

@@ -8,18 +8,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs/client_implementations/persistent_volume/file_layout"
-	"io/fs"
-	"math"
-	"net"
-	"net/http"
-	"os"
-	"path"
-	"path/filepath"
-	"runtime"
-	"strings"
-	"time"
-
 	"github.com/kurtosis-tech/kurtosis/api/golang/core/kurtosis_core_rpc_api_bindings"
 	"github.com/kurtosis-tech/kurtosis/api/golang/engine/kurtosis_engine_rpc_api_bindings/kurtosis_engine_rpc_api_bindingsconnect"
 	enclaveApi "github.com/kurtosis-tech/kurtosis/api/golang/http_rest/server/core_rest_api"
@@ -39,6 +27,7 @@ import (
 	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs"
 	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs/client_implementations/kurtosis_backend"
 	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs/client_implementations/persistent_volume"
+	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs/client_implementations/persistent_volume/file_layout"
 	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs/client_implementations/persistent_volume/log_file_manager"
 	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs/client_implementations/persistent_volume/logs_clock"
 	"github.com/kurtosis-tech/kurtosis/engine/server/engine/centralized_logs/client_implementations/persistent_volume/stream_logs_strategy"
@@ -57,6 +46,17 @@ import (
 	echomiddleware "github.com/labstack/echo/v4/middleware"
 	"github.com/rs/cors"
 	"github.com/sirupsen/logrus"
+	"io/fs"
+	"math"
+	"net"
+	"net/http"
+	_ "net/http/pprof"
+	"os"
+	"path"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"time"
 )
 
 const (
@@ -73,6 +73,7 @@ const (
 	functionPathSeparator     = "."
 	emptyFunctionName         = ""
 	webappPortAddr            = ":9711"
+	pprofPath                 = "/debug/pprof/"
 
 	remoteBackendConfigFilename = "remote_backend_config.json"
 	pathToStaticFolder          = "/run/webapp"
@@ -213,8 +214,9 @@ func runMain() error {
 		}
 		logrus.Debugf("Created environment js file with content: \n%s", envJsFileContent)
 
+		handler := http.NewServeMux()
 		fileServer := http.FileServer(http.Dir(pathToStaticFolder))
-		handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		handler.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 			path, err := filepath.Abs(r.URL.Path)
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusBadRequest)
@@ -236,6 +238,7 @@ func runMain() error {
 			w.Header().Add("Cache-Control", "no-store")
 			fileServer.ServeHTTP(w, r)
 		})
+		handler.Handle(pprofPath, http.HandlerFunc(http.DefaultServeMux.ServeHTTP))
 
 		err := http.ListenAndServe(webappPortAddr, handler)
 		if err != nil {

engine/server/engine/server/engine_connect_server_service.go

@@ -366,8 +366,10 @@ func (service *EngineConnectServerService) GetServiceLogs(ctx context.Context, c
 				logrus.Debug("Exiting the stream because an error from the logs database client was received through the error chan.")
 				return stacktrace.Propagate(err, "An error occurred streaming user service logs.")
 			}
-			logrus.Debug("Exiting the stream loop after receiving a close signal from the error chan")
-			return nil
+			if len(serviceLogsByServiceUuidChan) == 0 {
+				logrus.Debug("Exiting the stream loop after receiving a close signal from the error chan")
+				return nil
+			}
 		}
 	}
 }