From cd31bdece1983ea3523b89aef1db018ffc8b3ef0 Mon Sep 17 00:00:00 2001
From: rcourtman <courtmanr@gmail.com>
Date: Sat, 22 Nov 2025 07:48:34 +0000
Subject: [PATCH] Add log level control to host agent

Related to #742
---
 cmd/pulse-host-agent/main.go | 37 +++++++++++++++++++++++++++++++++++-
 docs/HOST_AGENT.md           |  1 +
 internal/hostagent/agent.go  | 13 +++++++++++--
 3 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/cmd/pulse-host-agent/main.go b/cmd/pulse-host-agent/main.go
index 379761d70..afdfa1113 100644
--- a/cmd/pulse-host-agent/main.go
+++ b/cmd/pulse-host-agent/main.go
@@ -29,7 +29,9 @@ func (m *multiValue) Set(value string) error {
 func main() {
 	cfg := loadConfig()
 
-	logger := zerolog.New(os.Stdout).With().Timestamp().Logger()
+	zerolog.SetGlobalLevel(cfg.LogLevel)
+
+	logger := zerolog.New(os.Stdout).Level(cfg.LogLevel).With().Timestamp().Logger()
 	cfg.Logger = &logger
 
 	// Check if we should run as a Windows service
@@ -69,6 +71,7 @@ func loadConfig() hostagent.Config {
 	envInsecure := utils.GetenvTrim("PULSE_INSECURE_SKIP_VERIFY")
 	envTags := utils.GetenvTrim("PULSE_TAGS")
 	envRunOnce := utils.GetenvTrim("PULSE_ONCE")
+	envLogLevel := utils.GetenvTrim("LOG_LEVEL")
 
 	defaultInterval := 30 * time.Second
 	if envInterval != "" {
@@ -85,6 +88,7 @@ func loadConfig() hostagent.Config {
 	insecureFlag := flag.Bool("insecure", utils.ParseBool(envInsecure), "Skip TLS certificate verification")
 	runOnceFlag := flag.Bool("once", utils.ParseBool(envRunOnce), "Collect and send a single report, then exit")
 	showVersion := flag.Bool("version", false, "Print the agent version and exit")
+	logLevelFlag := flag.String("log-level", defaultLogLevel(envLogLevel), "Log level: debug, info, warn, error")
 
 	var tagFlags multiValue
 	flag.Var(&tagFlags, "tag", "Tag to apply to this host (repeatable)")
@@ -112,6 +116,12 @@ func loadConfig() hostagent.Config {
 		interval = 30 * time.Second
 	}
 
+	logLevel, err := parseLogLevel(*logLevelFlag)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: %v\n", err)
+		os.Exit(1)
+	}
+
 	tags := gatherTags(envTags, tagFlags)
 
 	return hostagent.Config{
@@ -123,6 +133,7 @@ func loadConfig() hostagent.Config {
 		Tags:               tags,
 		InsecureSkipVerify: *insecureFlag,
 		RunOnce:            *runOnceFlag,
+		LogLevel:           logLevel,
 	}
 }
 
@@ -144,3 +155,27 @@ func gatherTags(env string, flags []string) []string {
 	}
 	return tags
 }
+
+func parseLogLevel(value string) (zerolog.Level, error) {
+	normalized := strings.ToLower(strings.TrimSpace(value))
+	if normalized == "" {
+		return zerolog.InfoLevel, nil
+	}
+
+	level, err := zerolog.ParseLevel(normalized)
+	if err != nil {
+		return zerolog.InfoLevel, fmt.Errorf("invalid log level %q: must be debug, info, warn, or error", value)
+	}
+	if level < zerolog.DebugLevel || level > zerolog.ErrorLevel {
+		return zerolog.InfoLevel, fmt.Errorf("invalid log level %q: must be debug, info, warn, or error", value)
+	}
+
+	return level, nil
+}
+
+func defaultLogLevel(envValue string) string {
+	if strings.TrimSpace(envValue) == "" {
+		return "info"
+	}
+	return envValue
+}
diff --git a/docs/HOST_AGENT.md b/docs/HOST_AGENT.md
index 95b67c468..a7583e4be 100644
--- a/docs/HOST_AGENT.md
+++ b/docs/HOST_AGENT.md
@@ -204,6 +204,7 @@ Start-Service -Name PulseHostAgent
 | `--url` | Pulse base URL (defaults to `http://localhost:7655`) |
 | `--token` | API token with the `host-agent:report` scope |
 | `--interval` | Polling interval (`30s` default) |
+| `--log-level` | Log verbosity (`debug`, `info`, `warn`, `error`; defaults to `info`). Also respects `LOG_LEVEL`. Use `warn` on noisy journald setups. |
 | `--hostname` | Override reported hostname |
 | `--agent-id` | Override agent identifier (used as dedupe key) |
 | `--tag` | Optional tag(s) to annotate the host (repeatable) |
diff --git a/internal/hostagent/agent.go b/internal/hostagent/agent.go
index a876dcbb0..22ef0ca4e 100644
--- a/internal/hostagent/agent.go
+++ b/internal/hostagent/agent.go
@@ -30,6 +30,7 @@ type Config struct {
 	Tags               []string
 	InsecureSkipVerify bool
 	RunOnce            bool
+	LogLevel           zerolog.Level
 	Logger             *zerolog.Logger
 }
 
@@ -61,12 +62,20 @@ func New(cfg Config) (*Agent, error) {
 		cfg.Interval = defaultInterval
 	}
 
+	if zerolog.GlobalLevel() == zerolog.DebugLevel && cfg.LogLevel != zerolog.DebugLevel {
+		zerolog.SetGlobalLevel(cfg.LogLevel)
+	}
+
 	if cfg.Logger == nil {
-		defaultLogger := zerolog.New(zerolog.NewConsoleWriter()).With().Timestamp().Logger()
+		defaultLogger := zerolog.New(zerolog.NewConsoleWriter()).
+			Level(cfg.LogLevel).
+			With().
+			Timestamp().
+			Logger()
 		cfg.Logger = &defaultLogger
 	}
 
-	logger := cfg.Logger.With().Str("component", "host-agent").Logger()
+	logger := cfg.Logger.Level(cfg.LogLevel).With().Str("component", "host-agent").Logger()
 
 	if strings.TrimSpace(cfg.APIToken) == "" {
 		return nil, fmt.Errorf("api token is required")