chore: Improve agent logging (coder#3483)

Author: kylecarbs

agent/agent.go

@@ -129,6 +129,7 @@ func (a *agent) run(ctx context.Context) {
 	// An exponential back-off occurs when the connection is failing to dial.
 	// This is to prevent server spam in case of a coderd outage.
 	for retrier := retry.New(50*time.Millisecond, 10*time.Second); retrier.Wait(ctx); {
+		a.logger.Info(ctx, "connecting")
 		metadata, peerListener, err = a.dialer(ctx, a.logger)
 		if err != nil {
 			if errors.Is(err, context.Canceled) {
@@ -255,6 +256,7 @@ func (a *agent) handlePeerConn(ctx context.Context, conn *peer.Conn) {
 }
 
 func (a *agent) init(ctx context.Context) {
+	a.logger.Info(ctx, "generating host key")
 	// Clients' should ignore the host key when connecting.
 	// The agent needs to authenticate with coderd to SSH,
 	// so SSH authentication doesn't improve security.

cli/agent.go

@@ -73,6 +73,7 @@ func workspaceAgent() *cobra.Command {
 				return nil
 			}
 
+			logger.Info(cmd.Context(), "starting agent", slog.F("url", coderURL), slog.F("auth", auth))
 			client := codersdk.New(coderURL)
 
 			if pprofEnabled {
@@ -138,6 +139,7 @@ func workspaceAgent() *cobra.Command {
 			}
 
 			if exchangeToken != nil {
+				logger.Info(cmd.Context(), "exchanging identity token")
 				// Agent's can start before resources are returned from the provisioner
 				// daemon. If there are many resources being provisioned, this time
 				// could be significant. This is arbitrarily set at an hour to prevent