From dd5c1cf2118cbfd242b09c54f9899f58c2e820ab Mon Sep 17 00:00:00 2001
From: Lukasz Okraszewski <lukasz.okraszewski@goteleport.com>
Date: Wed, 30 Jul 2025 14:44:44 +0100
Subject: [PATCH 1/2] [tctl/top] Parse teleport config file

Add config file parsing to `tctl top` command,
this normally is done on client configuration
but since the `top` client does not make use
of the common tctl client it previously did not
support the local config file.
This this change it is now possible to use a custom
datadir for the debug socket.

changelog: tctl top respects local teleport config file
---
 tool/tctl/common/top/command.go | 36 ++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/tool/tctl/common/top/command.go b/tool/tctl/common/top/command.go
index 14aeaf20597ea..979edd5e90455 100644
--- a/tool/tctl/common/top/command.go
+++ b/tool/tctl/common/top/command.go
@@ -26,6 +26,7 @@ import (
 	dto "github.com/prometheus/client_model/go"
 
 	"github.com/gravitational/teleport/lib/client/debug"
+	"github.com/gravitational/teleport/lib/config"
 	"github.com/gravitational/teleport/lib/service/servicecfg"
 	commonclient "github.com/gravitational/teleport/tool/tctl/common/client"
 	tctlcfg "github.com/gravitational/teleport/tool/tctl/common/config"
@@ -36,6 +37,7 @@ import (
 // Teleport /metrics endpoint and displays diagnostic
 // information an easy to consume way.
 type Command struct {
+	global        *tctlcfg.GlobalCLIFlags
 	config        *servicecfg.Config
 	top           *kingpin.CmdClause
 	diagURL       string
@@ -45,8 +47,9 @@ type Command struct {
 const defaultDiagAddr = "http://127.0.0.1:3000"
 
 // Initialize sets up the "tctl top" command.
-func (c *Command) Initialize(app *kingpin.Application, _ *tctlcfg.GlobalCLIFlags, config *servicecfg.Config) {
+func (c *Command) Initialize(app *kingpin.Application, global *tctlcfg.GlobalCLIFlags, config *servicecfg.Config) {
 	c.config = config
+	c.global = global
 	c.top = app.Command("top", "Report diagnostic information.")
 	c.top.Arg("diag-addr", "Diagnostic HTTP URL").StringVar(&c.diagURL)
 	c.top.Arg("refresh", "Refresh period").Default("5s").DurationVar(&c.refreshPeriod)
@@ -93,12 +96,43 @@ func (c *Command) newMetricsClient(ctx context.Context) (string, MetricsClient,
 		"connecting to Teleport metrics server")
 }
 
+func (c *Command) initConfig() error {
+	var fileConf *config.FileConfig
+	var err error
+	if c.global.ConfigFile != "" {
+		fileConf, err = config.ReadConfigFile(c.global.ConfigFile)
+		if err != nil {
+			return trace.Wrap(err)
+		}
+	}
+
+	if c.global.ConfigString != "" {
+		fileConf, err = config.ReadFromString(c.global.ConfigString)
+		if err != nil {
+			return trace.Wrap(err)
+		}
+	}
+
+	if fileConf != nil {
+		if err = config.ApplyFileConfig(fileConf, c.config); err != nil {
+			return trace.Wrap(err)
+		}
+	}
+
+	return nil
+}
+
 // TryRun attempts to run subcommands.
 func (c *Command) TryRun(ctx context.Context, cmd string, _ commonclient.InitFunc) (match bool, err error) {
 	if cmd != c.top.FullCommand() {
 		return false, nil
 	}
 
+	err = c.initConfig()
+	if err != nil {
+		return true, trace.Wrap(err)
+	}
+
 	addr, metricsClient, err := c.newMetricsClient(ctx)
 	if err != nil {
 		return true, trace.Wrap(err)

From 185e08962596061d3ad3dcae87064ac462f7659c Mon Sep 17 00:00:00 2001
From: Lukasz Okraszewski <lukasz.okraszewski@goteleport.com>
Date: Wed, 30 Jul 2025 16:27:38 +0100
Subject: [PATCH 2/2] apply review feedback

---
 tool/tctl/common/top/command.go | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tool/tctl/common/top/command.go b/tool/tctl/common/top/command.go
index 979edd5e90455..593fe71db4b34 100644
--- a/tool/tctl/common/top/command.go
+++ b/tool/tctl/common/top/command.go
@@ -96,6 +96,13 @@ func (c *Command) newMetricsClient(ctx context.Context) (string, MetricsClient,
 		"connecting to Teleport metrics server")
 }
 
+// initConfig populates the [*servicecfg.Config]
+//
+// This is required by `tctl top` as it does not make use of the [commonclient.InitFunc]
+// which lazy loads the configuration during client creation, meaning the required configuration
+// fields are not initilized as this command uses a standalone metrics client instead on a local connection.
+//
+// TODO(okraport): remove this workaround once the caller can safely parse the teleport config file without common client.
 func (c *Command) initConfig() error {
 	var fileConf *config.FileConfig
 	var err error
@@ -128,8 +135,7 @@ func (c *Command) TryRun(ctx context.Context, cmd string, _ commonclient.InitFun
 		return false, nil
 	}
 
-	err = c.initConfig()
-	if err != nil {
+	if err := c.initConfig(); err != nil {
 		return true, trace.Wrap(err)
 	}