Improve agent update logging and installer warnings (related to #737)

internal/dockeragent/agent.go

@@ -1536,7 +1536,7 @@ func detectHostRemovedError(body []byte) string {
 func (a *Agent) checkForUpdates(ctx context.Context) {
 	// Skip updates if disabled via config
 	if a.cfg.DisableAutoUpdate {
-		a.logger.Debug().Msg("Skipping update check - auto-update disabled")
+		a.logger.Info().Msg("Skipping update check - auto-update disabled")
 		return
 	}
 

internal/dockeragent/agent_log_test.go

@@ -0,0 +1,40 @@
+package dockeragent
+
+import (
+	"bytes"
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/rs/zerolog"
+)
+
+func TestCheckForUpdatesLog(t *testing.T) {
+	// Create a buffer to capture logs
+	var buf bytes.Buffer
+	logger := zerolog.New(&buf)
+
+	// Create an agent with DisableAutoUpdate set to true
+	agent := &Agent{
+		cfg: Config{
+			DisableAutoUpdate: true,
+		},
+		logger: logger,
+	}
+
+	// Call checkForUpdates
+	agent.checkForUpdates(context.Background())
+
+	// Check logs
+	output := buf.String()
+	expected := "Skipping update check - auto-update disabled"
+	if !strings.Contains(output, expected) {
+		t.Errorf("expected log message %q not found in output:\n%s", expected, output)
+	}
+
+	// Verify log level is INFO (zerolog default level is debug? no, default global is info, but logger.Info() writes regardless)
+	// Zerolog JSON output contains "level":"info"
+	if !strings.Contains(output, `"level":"info"`) {
+		t.Errorf("expected log level info, got output:\n%s", output)
+	}
+}

scripts/install-docker-agent.sh

@@ -1805,7 +1805,7 @@ if command -v curl &> /dev/null || command -v wget &> /dev/null; then
 
     if [[ -n "$SERVER_INFO" ]] && echo "$SERVER_INFO" | grep -q '"isDevelopment"[[:space:]]*:[[:space:]]*true'; then
         NO_AUTO_UPDATE_FLAG=" --no-auto-update"
-        log_info 'Development server detected – auto-update disabled'
+        log_warn "Server is in development mode; disabling agent auto-update"
     fi
 
     if [[ -n "$NO_AUTO_UPDATE_FLAG" ]] && ! "$AGENT_PATH" --help 2>&1 | grep -q -- '--no-auto-update'; then