Fix detection if the collector is running as service on Windows (open…

…-telemetry#9042)

**Description:**
Fix run as a service detection on Windows. Instead of trying to detect
if it is a service or not, for which both `svc.IsAnInteractiveSession()`
and `svc.IsWindowsService()` are somehow broken, try to run as a Windows
service, if that fails fallback to run as an interactive process. This
follows a recommendation of the Windows [service API
documentation](https://learn.microsoft.com/en-us/windows/win32/api/winsvc/nf-winsvc-startservicectrldispatchera#return-value).
The new code calls `svc.Run` and in case of error checks for
`windows.ERROR_FAILED_SERVICE_CONTROLLER_CONNECT`. If this is the error
the application can safely assume that it is not running as a service.

The duration of a call to `svc.Run` failing with this error was below 3
microseconds in the current GH runner and below 5 microseconds on my
box. While this value seems fine for startup I'm keeping the
`NO_WINDOWS_SERVICE` option instead of deprecating it (it doesn't seem
worth the trouble of deprecating it).

**Link to tracking Issue:**
Fix open-telemetry#7350

**Testing:**
Fix tested on the Splunk fork that deploys the collector as a service
and as an interactive process on Windows containers.

**Documentation:**
Added changelog.

.chloggen/fix-running-as-service-detection.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: cmd/otelcorecol
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix the code detecting if the collector is running as a service on Windows.
+
+# One or more tracking issues or pull requests related to the change
+issues: [7350]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: Removed the `NO_WINDOWS_SERVICE` environment variable given it is not needed anymore.
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

cmd/builder/internal/builder/templates/main_windows.go.tmpl

@@ -6,41 +6,23 @@
 package main
 
 import (
+	"errors"
 	"fmt"
-	"os"
+	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/svc"
 	"go.opentelemetry.io/collector/otelcol"
 )
 
 func run(params otelcol.CollectorSettings) error {
-	if useInteractiveMode, err := checkUseInteractiveMode(); err != nil {
-		return err
-	} else if useInteractiveMode {
-		return runInteractive(params)
-	} else {
-		return runService(params)
-	}
-}
-
-func checkUseInteractiveMode() (bool, error) {
-	// If environment variable NO_WINDOWS_SERVICE is set with any value other
-	// than 0, use interactive mode instead of running as a service. This should
-	// be set in case running as a service is not possible or desired even
-	// though the current session is not detected to be interactive
-	if value, present := os.LookupEnv("NO_WINDOWS_SERVICE"); present && value != "0" {
-		return true, nil
-	}
-
-	isInteractiveSession, err := svc.IsAnInteractiveSession()
-	if err != nil {
-		return false, fmt.Errorf("failed to determine if we are running in an interactive session: %w", err)
-	}
-	return isInteractiveSession, nil
-}
-
-func runService(params otelcol.CollectorSettings) error {
-	// do not need to supply service name when startup is invoked through Service Control Manager directly
+	// No need to supply service name when startup is invoked through
+	// the Service Control Manager directly.
 	if err := svc.Run("", otelcol.NewSvcHandler(params)); err != nil {
+		if errors.Is(err, windows.ERROR_FAILED_SERVICE_CONTROLLER_CONNECT) {
+			// Per https://learn.microsoft.com/en-us/windows/win32/api/winsvc/nf-winsvc-startservicectrldispatchera#return-value
+			// this means that the process is not running as a service, so run interactively.
+			return runInteractive(params)
+		}
+
 		return fmt.Errorf("failed to start collector server: %w", err)
 	}
 

docs/troubleshooting.md

@@ -283,7 +283,7 @@ configuration issue. This could be due to a firewall, DNS, or proxy
 issue. Note that the Collector does have
 [proxy support](https://github.com/open-telemetry/opentelemetry-collector/tree/main/exporter#proxy-support).
 
-### Startup failing in Windows Docker containers
+### Startup failing in Windows Docker containers (v0.90.1 and earlier)
 
 The process may fail to start in a Windows Docker container with the following
 error: `The service process could not connect to the service controller`. In