diff --git a/swh/scanner/exceptions.py b/swh/scanner/exceptions.py
new file mode 100644
index 0000000..5c8d6d8
--- /dev/null
+++ b/swh/scanner/exceptions.py
@@ -0,0 +1,8 @@
+class InvalidPath(Exception):
+    def __str__(self):
+        return 'the provided path is invalid: "%s"' % self.args
+
+
+class APIError(Exception):
+    def __str__(self):
+        return 'API Error: "%s"' % self.args
diff --git a/swh/scanner/logger.py b/swh/scanner/logger.py
new file mode 100644
index 0000000..b45e7e3
--- /dev/null
+++ b/swh/scanner/logger.py
@@ -0,0 +1,61 @@
+# Copyright (C) 2020  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import logging
+
+
+logger = None
+
+
+def init(**kwargs):
+    def decorate(func):
+        for k in kwargs:
+            setattr(func, k, kwargs[k])
+        return func
+    return decorate
+
+
+def setup_logger(verbose: bool) -> None:
+    global logger
+    console = logging.FileHandler('scan.log')
+    console.setLevel(logging.DEBUG)
+    formatter = logging.Formatter('%(asctime)s | %(levelname)s: %(message)s')
+    console.setFormatter(formatter)
+
+    logger = logging.getLogger('debug')
+    logger.addHandler(console)
+    if not verbose:
+        logger.propagate = False
+
+
+@init(count=0)
+def log_queries(n: int) -> None:
+    if logger is not None:
+        log_queries.count += n
+
+
+def log_counters() -> None:
+    if logger is not None:
+        logger.info('number of queries: %s' % log_queries.count)
+
+
+def error(*args) -> None:
+    if logger is not None:
+        logger.error(args)
+
+
+def warning(*args) -> None:
+    if logger is not None:
+        logger.warning(args)
+
+
+def info(*args) -> None:
+    if logger is not None:
+        logger.info(args)
+
+
+def debug(*args):
+    if logger is not None:
+        logger.debug(args)
diff --git a/swh/scanner/model.py b/swh/scanner/model.py
new file mode 100644
index 0000000..c46e618
--- /dev/null
+++ b/swh/scanner/model.py
@@ -0,0 +1,76 @@
+# Copyright (C) 2020  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+from __future__ import annotations
+from pathlib import PosixPath
+from typing import Any, Dict
+from enum import Enum
+
+from swh.model.identifiers import (
+    DIRECTORY, CONTENT
+)
+
+
+class Color(Enum):
+    blue = '\033[94m'
+    green = '\033[92m'
+    red = '\033[91m'
+    end = '\033[0m'
+
+
+def colorize(text: str, color: Color):
+    return color.value + text + Color.end.value
+
+
+class Tree:
+    """Representation of a file system structure
+    """
+    def __init__(self, father: Tree, path: PosixPath):
+        self.father = father
+        self.path = path
+        self.otype = DIRECTORY if path.is_dir() else CONTENT
+        self.pid = ''
+        self.children: Dict[PosixPath, Tree] = {}
+
+    def addNode(self, path: PosixPath, pid: str = None) -> None:
+        """Recursively add a new node path
+        """
+        relative_path = path.relative_to(self.path)
+
+        if relative_path == PosixPath('.'):
+            if pid is not None:
+                self.pid = pid
+            return
+
+        new_path = self.path.joinpath(relative_path.parts[0])
+        if new_path not in self.children:
+            self.children[new_path] = Tree(self, new_path)
+
+        self.children[new_path].addNode(path, pid)
+
+    def show(self) -> None:
+        """Print all the tree"""
+        print(Color.blue.value+str(self.path)+Color.end.value)
+        self.printChildren()
+
+    def printChildren(self, inc: int = 0) -> None:
+        for path, node in self.children.items():
+            self.printNode(node, inc)
+            if node.children:
+                node.printChildren(inc+1)
+
+    def printNode(self, node: Any, inc: int) -> None:
+        rel_path = str(node.path.relative_to(self.path))
+        if node.otype == DIRECTORY:
+            if node.pid:
+                print('│   '*inc + colorize(rel_path, Color.blue) + '/')
+            else:
+                print('│   '*inc + colorize(rel_path, Color.red) + '/')
+
+        if node.otype == CONTENT:
+            if node.pid:
+                print('│   '*inc + colorize(rel_path, Color.green))
+            else:
+                print('│   '*inc + colorize(rel_path, Color.red))