From 8eea6468b764dea27aaf6a92450f907f2b7f6a5a Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Fri, 23 Aug 2019 11:36:19 +1000
Subject: [PATCH] wacom: add a session id field to make it easier to find log
 files

The session id is a UUID, postfixed by an incrementing number. The UUID stays
the same for Tuhi's livetime, the number increments with every bluetooth
connect/disconnect. Result is e.g. 4e55c30035d043ce9f6f4914fb223820-2.

This session id is printed to the log file, added to the YAML raw logs and to
the JSON file, making it easier which log part resulted in which drawing, etc.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
---
 DBusInterface.md |  6 ++++++
 tuhi/drawing.py  |  2 ++
 tuhi/wacom.py    | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/DBusInterface.md b/DBusInterface.md
index 39a7615..a201966 100644
--- a/DBusInterface.md
+++ b/DBusInterface.md
@@ -336,12 +336,17 @@ files). The JSON objects are "drawing" (the root object), "strokes",
 class Drawing {
         version: uint32
         devicename: string
+        sessionid: string            // used for debugging
         dimensions: [uint32, uint32] // x/y physical dimensions in µm
         timestamp: uint64
         strokes: [ Stroke, Stroke, ...]
 }
 ```
 
+A session id is a random string that identifies a Tuhi session. This is
+debugging information only, it makes it possible to associate a JSON file
+with the corresponding sequence in the log. Do not use in clients.
+
 The **strokes** list contains all strokes of a single drawing, each stroke
 consisting of a number of **points**.
 
@@ -367,6 +372,7 @@ An expanded file looks like this:
 {
    "version" : 1,                       // JSON file format version number
    "devicename":  "Wacom Bamboo Spark", 
+   "sessionid": "somerandomstring-1",
    "dimensions": [ 100000, 200000],      // width/height in µm
    "timestamp" : 12345,
    "strokes" : [
diff --git a/tuhi/drawing.py b/tuhi/drawing.py
index 04adb49..28821ed 100644
--- a/tuhi/drawing.py
+++ b/tuhi/drawing.py
@@ -97,6 +97,7 @@ class Drawing(GObject.Object):
         self.timestamp = timestamp  # unix seconds
         self.strokes = []
         self._current_stroke = -1
+        self.session_id = 'unset'
 
     def seal(self):
         # Drop empty strokes
@@ -130,6 +131,7 @@ class Drawing(GObject.Object):
         json_data = {
             'version': self.JSON_FILE_FORMAT_VERSION,
             'devicename': self.name,
+            'sessionid': self.session_id,
             'dimensions': list(self.dimensions),
             'timestamp': self.timestamp,
             'strokes': [s.to_dict() for s in self.strokes]
diff --git a/tuhi/wacom.py b/tuhi/wacom.py
index 8b6db19..82cc6a1 100644
--- a/tuhi/wacom.py
+++ b/tuhi/wacom.py
@@ -40,6 +40,20 @@ SYSEVENT_NOTIFICATION_SERVICE_UUID = '3a340720-c572-11e5-86c5-0002a5d5c51b'  # N
 SYSEVENT_NOTIFICATION_CHRC_UUID    = '3a340721-c572-11e5-86c5-0002a5d5c51b'  # NOQA
 
 
+class IDGenerator(object):
+    _session = uuid.uuid4().hex
+    _instance = 0
+
+    @classmethod
+    def current(cls):
+        return f'{cls._session}-{cls._instance}'
+
+    @classmethod
+    def next(cls):
+        cls._instance += 1
+        return cls.current()
+
+
 @enum.unique
 class DeviceMode(enum.Enum):
     REGISTER = 1
@@ -198,6 +212,9 @@ class DataLogger(object):
         path = Path(self.logdir, fname)
         self.logfile = open(path, 'w+')
 
+        session_id = IDGenerator.next()
+        self.logger.debug(f'sessionid: {session_id}')
+        self.logfile.write(f'sessionid: {session_id}\n')
         self.logfile.write(f'name: {self.device.name}\n')
         self.logfile.write(f'bluetooth: {self.btaddr}\n')
         self.logfile.write(f'time: {timestamp} # host time: {time.strftime("%Y-%m-%d %H:%M:%S")}\n')
@@ -661,6 +678,7 @@ class WacomProtocolBase(WacomProtocolLowLevelComm):
 
         f = StrokeFile(data)
         drawing = Drawing(self.device.name, (self.width, self.height), timestamp)
+        drawing.session_id = IDGenerator.current()
         ps = self.point_size
 
         def normalize(p):