agent: Fix misaligned contextual k/v logging arguments. (#25629)

Arguments passed to hclog log lines should always have an even
number to provide the expected k/v output.

client/allocrunner/taskrunner/api_hook.go

@@ -97,7 +97,7 @@ func (h *apiHook) Stop(ctx context.Context, req *interfaces.TaskStopRequest, res
 	if h.ln != nil {
 		if err := h.ln.Close(); err != nil {
 			if !errors.Is(err, net.ErrClosed) {
-				h.logger.Debug("error closing task listener: %v", err)
+				h.logger.Debug("error closing task listener", "error", err)
 			}
 		}
 		h.ln = nil

client/allocrunner/taskrunner/dynamic_users_hook.go

@@ -77,7 +77,7 @@ func (h *dynamicUsersHook) Prestart(_ context.Context, request *interfaces.TaskP
 	// allocate an unused UID/GID from the pool
 	ugid, err := h.pool.Acquire()
 	if err != nil {
-		h.logger.Error("unable to acquire anonymous UID/GID: %v", err)
+		h.logger.Error("unable to acquire anonymous UID/GID", "error", err)
 		return err
 	}
 

client/allocrunner/taskrunner/identity_hook.go

@@ -134,12 +134,13 @@ func (h *identityHook) watchIdentity(wid *structs.WorkloadIdentity, runCh chan s
 			if signedWID == nil {
 				// The only way to hit this should be a bug as it indicates the server
 				// did not sign an identity for a task on this alloc.
-				h.logger.Error("missing workload identity %q", wid.Name)
+				h.logger.Error("missing workload identity", "identity", wid.Name)
 				return
 			}
 
 			if err := h.setAltToken(wid, signedWID.JWT); err != nil {
-				h.logger.Error(err.Error())
+				h.logger.Error("failed to set workload identity token",
+					"identity", wid.Name, "error", err)
 			}
 
 			// Skip ChangeMode on firstRun and notify caller it can proceed
@@ -148,7 +149,8 @@ func (h *identityHook) watchIdentity(wid *structs.WorkloadIdentity, runCh chan s
 				case runCh <- struct{}{}:
 				default:
 					// Not great but not necessarily fatal
-					h.logger.Warn("task started before identity %q was fetched", wid.Name)
+					h.logger.Warn("task started before identity was fetched",
+						"identity", wid.Name)
 				}
 
 				firstRun = false