Make Tensorboard a late import (it was implicitly installed by basicsr)

modules/textual_inversion/textual_inversion.py

@@ -11,7 +11,6 @@ import safetensors.torch
 
 import numpy as np
 from PIL import Image, PngImagePlugin
-from torch.utils.tensorboard import SummaryWriter
 
 from modules import shared, devices, sd_hijack, sd_models, images, sd_samplers, sd_hijack_checkpoint, errors, hashes
 import modules.textual_inversion.dataset
@@ -344,6 +343,7 @@ def write_loss(log_directory, filename, step, epoch_len, values):
         })
 
 def tensorboard_setup(log_directory):
+    from torch.utils.tensorboard import SummaryWriter
     os.makedirs(os.path.join(log_directory, "tensorboard"), exist_ok=True)
     return SummaryWriter(
             log_dir=os.path.join(log_directory, "tensorboard"),
@@ -448,8 +448,12 @@ def train_embedding(id_task, embedding_name, learn_rate, batch_size, gradient_st
     shared.state.textinfo = f"Preparing dataset from {html.escape(data_root)}..."
     old_parallel_processing_allowed = shared.parallel_processing_allowed
 
+    tensorboard_writer = None
     if shared.opts.training_enable_tensorboard:
-        tensorboard_writer = tensorboard_setup(log_directory)
+        try:
+            tensorboard_writer = tensorboard_setup(log_directory)
+        except ImportError:
+            errors.report("Error initializing tensorboard", exc_info=True)
 
     pin_memory = shared.opts.pin_memory
 
@@ -622,7 +626,7 @@ def train_embedding(id_task, embedding_name, learn_rate, batch_size, gradient_st
                         last_saved_image, last_text_info = images.save_image(image, images_dir, "", p.seed, p.prompt, shared.opts.samples_format, processed.infotexts[0], p=p, forced_filename=forced_filename, save_to_dirs=False)
                         last_saved_image += f", prompt: {preview_text}"
 
-                        if shared.opts.training_enable_tensorboard and shared.opts.training_tensorboard_save_images:
+                        if tensorboard_writer and shared.opts.training_tensorboard_save_images:
                             tensorboard_add_image(tensorboard_writer, f"Validation at epoch {epoch_num}", image, embedding.step)
 
                     if save_image_with_stored_embedding and os.path.exists(last_saved_file) and embedding_yet_to_be_embedded: