From 7d5b8ee77d443c88547759ab007cbe047d103ade Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Mon, 28 Sep 2026 08:37:18 +0200
Subject: [PATCH 01/15] Switch to daemon thread

---
 exasol/telemetry/client/setup.py  | 10 ++++++++++
 exasol/telemetry/client/worker.py |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/exasol/telemetry/client/setup.py b/exasol/telemetry/client/setup.py
index e5ee75d..344db09 100644
--- a/exasol/telemetry/client/setup.py
+++ b/exasol/telemetry/client/setup.py
@@ -1,3 +1,4 @@
+import atexit
 import os
 import typing as tt
 from urllib.parse import urlparse
@@ -52,6 +53,14 @@ def setup_verbose_if_needed():
     verbose.setup_logging()
 
 
+def setup_exit_handlers():
+    """
+    Trigger shutdown on exit of application.
+    Function have to be called only once - during the setup.
+    """
+    atexit.register(shutdown)
+
+
 def setup(endpoint: tt.Optional[str] = None, disable: tt.Optional[bool] = None) -> bool:
     """
     Telemetry client setup function.
@@ -99,6 +108,7 @@ def setup(endpoint: tt.Optional[str] = None, disable: tt.Optional[bool] = None)
     config.store(conf)
     if enabled:
         setup_verbose_if_needed()
+        setup_exit_handlers()
         worker.start_worker()
     verbose.log("Setup is done, enabled=%s", conf.enabled)
     return conf.enabled
diff --git a/exasol/telemetry/client/worker.py b/exasol/telemetry/client/worker.py
index 5277689..41de97e 100644
--- a/exasol/telemetry/client/worker.py
+++ b/exasol/telemetry/client/worker.py
@@ -257,7 +257,7 @@ def start_worker() -> bool:
     if not config.was_enabled():
         return False
     _queue = queue.Queue(maxsize=MAX_QUEUE_CAPACITY)
-    _worker = threading.Thread(target=worker_proc, args=(_queue,))
+    _worker = threading.Thread(target=worker_proc, args=(_queue,), daemon=True)
     _worker.start()
     return True
 

From 7da8e9582c3f026cbbe086ee1dfd827e291e1ec9 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Mon, 28 Sep 2026 08:46:37 +0200
Subject: [PATCH 02/15] Fix setup logic

---
 exasol/telemetry/client/setup.py | 4 +++-
 test/unit/client/test_setup.py   | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/exasol/telemetry/client/setup.py b/exasol/telemetry/client/setup.py
index 344db09..31d8704 100644
--- a/exasol/telemetry/client/setup.py
+++ b/exasol/telemetry/client/setup.py
@@ -80,7 +80,9 @@ def setup(endpoint: tt.Optional[str] = None, disable: tt.Optional[bool] = None)
     False if it was disabled
     """
     if config.was_setup():
-        return config.was_enabled()
+        if disable is None or disable != config.was_enabled():
+            return config.was_enabled()
+        shutdown()
     val_endpoint = get_value(endpoint, config.ENV_ENDPOINT, config.DEFAULT_ENDPOINT)
 
     # Checking the presence of CI=true env variable
diff --git a/test/unit/client/test_setup.py b/test/unit/client/test_setup.py
index 3085c4c..8cd7385 100644
--- a/test/unit/client/test_setup.py
+++ b/test/unit/client/test_setup.py
@@ -80,8 +80,8 @@ def test_setup_env_disabled(
     assert not setup("http://endpoint")
     assert config.was_setup()
     assert not config.was_enabled()
-    # double-call to setup skips reconfiguration and returns the enable status
-    assert not setup(disable=False)
+    # double-call to setup skips reconfiguration if disable is the same
+    assert not setup(disable=True)
 
 
 def test_setup_env_enabled(

From 7144bb7f7ea4aa692a134e927d3f78d60754e152 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Mon, 28 Sep 2026 08:50:27 +0200
Subject: [PATCH 03/15] Prepare release

---
 doc/changes/changelog.md     | 2 ++
 doc/changes/changes_0.2.1.md | 9 +++++++++
 pyproject.toml               | 2 +-
 3 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 doc/changes/changes_0.2.1.md

diff --git a/doc/changes/changelog.md b/doc/changes/changelog.md
index e1874a0..1b26859 100644
--- a/doc/changes/changelog.md
+++ b/doc/changes/changelog.md
@@ -1,6 +1,7 @@
 # Changes
 
 * [unreleased](unreleased.md)
+* [0.2.1](changes_0.2.1.md)
 * [0.2.0](changes_0.2.0.md)
 * [0.1.6](changes_0.1.6.md)
 
@@ -9,6 +10,7 @@
 hidden:
 ---
 unreleased
+changes_0.2.1
 changes_0.2.0
 changes_0.1.6
 ```
diff --git a/doc/changes/changes_0.2.1.md b/doc/changes/changes_0.2.1.md
new file mode 100644
index 0000000..6b3819c
--- /dev/null
+++ b/doc/changes/changes_0.2.1.md
@@ -0,0 +1,9 @@
+# 0.2.1 - 2026-09-28
+
+## Summary
+
+Fix of threading block at the process exit.
+
+## Bugs
+
+- #10: Threading blocks at python exit
diff --git a/pyproject.toml b/pyproject.toml
index 621daf2..21fef52 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "exasol-telemetry-client"
-version = "0.2.0"
+version = "0.2.1"
 description = ""
 authors = [{ name = "Exasol AG", email = "opensource@exasol.com" }]
 requires-python = ">=3.10,<4.0"

From 11871c8081a643bbc8482f0c502b0ae91a41e8c5 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Tue, 29 Sep 2026 08:46:07 +0200
Subject: [PATCH 04/15] Timeout on join

---
 doc/changes/changes_0.2.1.md      | 3 ++-
 exasol/telemetry/client/worker.py | 5 ++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/doc/changes/changes_0.2.1.md b/doc/changes/changes_0.2.1.md
index 6b3819c..1a8ede0 100644
--- a/doc/changes/changes_0.2.1.md
+++ b/doc/changes/changes_0.2.1.md
@@ -2,8 +2,9 @@
 
 ## Summary
 
-Fix of threading block at the process exit.
+Fix of threading block at the process exit. Fixes `setup()` logic of reconfiguration (semi-private API).
 
 ## Bugs
 
 - #10: Threading blocks at python exit
+- Setup logic was wrong in one of tests.
diff --git a/exasol/telemetry/client/worker.py b/exasol/telemetry/client/worker.py
index 41de97e..ea0336d 100644
--- a/exasol/telemetry/client/worker.py
+++ b/exasol/telemetry/client/worker.py
@@ -19,6 +19,9 @@
 # requests' timeout value
 SEND_TIMEOUT_SECONDS = 30
 
+# how long to wait before thread exits
+THREAD_EXIT_TIMEOUT_SECONDS = 1
+
 # how long in seconds to wait before the first batch send
 DATA_SEND_FIRST_INTERVAL_SECONDS = 0.5
 
@@ -275,7 +278,7 @@ def stop_worker(flush_buffers: bool):
     if flush_buffers:
         _queue.put(WorkerMessage.make_send_buffers())
     _queue.put(WorkerMessage.make_terminate())
-    _worker.join()
+    _worker.join(timeout=THREAD_EXIT_TIMEOUT_SECONDS)
     _worker = None
     _queue = None
 

From 3a6447d0492d944921d62878c5e6c84d0176697e Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Tue, 29 Sep 2026 08:55:46 +0200
Subject: [PATCH 05/15] Removal of exit handlers

---
 exasol/telemetry/client/setup.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/exasol/telemetry/client/setup.py b/exasol/telemetry/client/setup.py
index 31d8704..1274e93 100644
--- a/exasol/telemetry/client/setup.py
+++ b/exasol/telemetry/client/setup.py
@@ -61,6 +61,13 @@ def setup_exit_handlers():
     atexit.register(shutdown)
 
 
+def drop_exit_handlers():
+    """
+    Removes previously configured exit handlers
+    """
+    atexit.unregister(shutdown)
+
+
 def setup(endpoint: tt.Optional[str] = None, disable: tt.Optional[bool] = None) -> bool:
     """
     Telemetry client setup function.
@@ -127,6 +134,7 @@ def shutdown(flush_buffers: bool = True):
         return
     verbose.log("Shutdown")
     worker.stop_worker(flush_buffers)
+    drop_exit_handlers()
 
 
 def disable():

From 22f85ff38786e7134b5857cb83c745943d8e8ee1 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Tue, 29 Sep 2026 08:57:16 +0200
Subject: [PATCH 06/15] Extra test case

---
 test/unit/client/test_setup.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/unit/client/test_setup.py b/test/unit/client/test_setup.py
index 8cd7385..9b3e4fe 100644
--- a/test/unit/client/test_setup.py
+++ b/test/unit/client/test_setup.py
@@ -82,6 +82,7 @@ def test_setup_env_disabled(
     assert not config.was_enabled()
     # double-call to setup skips reconfiguration if disable is the same
     assert not setup(disable=True)
+    assert setup(disable=False)
 
 
 def test_setup_env_enabled(

From 52c70d0942badedcde21b6c286f0eb1fabb32f5e Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Tue, 29 Sep 2026 08:57:50 +0200
Subject: [PATCH 07/15] Update release date

---
 doc/changes/changes_0.2.1.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/changes/changes_0.2.1.md b/doc/changes/changes_0.2.1.md
index 1a8ede0..8b94bbc 100644
--- a/doc/changes/changes_0.2.1.md
+++ b/doc/changes/changes_0.2.1.md
@@ -1,4 +1,4 @@
-# 0.2.1 - 2026-09-28
+# 0.2.1 - 2026-09-29
 
 ## Summary
 

From dd68238baf877c6377e31d60d3adf0537acaec99 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Tue, 29 Sep 2026 13:25:31 +0200
Subject: [PATCH 08/15] Docstrings update, fix of queue.put potential block

---
 exasol/telemetry/client/setup.py  | 6 ++++--
 exasol/telemetry/client/worker.py | 7 +++++--
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/exasol/telemetry/client/setup.py b/exasol/telemetry/client/setup.py
index 1274e93..0f757e8 100644
--- a/exasol/telemetry/client/setup.py
+++ b/exasol/telemetry/client/setup.py
@@ -70,13 +70,15 @@ def drop_exit_handlers():
 
 def setup(endpoint: tt.Optional[str] = None, disable: tt.Optional[bool] = None) -> bool:
     """
-    Telemetry client setup function.
+    Telemetry client setup function (should not be called from a client code).
 
     Explicitly given arguments have the highest priority.
     If they are not given, we check the environment variables (EXASOL_TELEMETRY_XXX),
     if no environment value, we use defaults (DEFAULT_XXX).
 
-    If setup() was called before, we return the enabled status and do not reconfigure.
+    If setup() was called before, we reconfigure only when previous disable
+    option was different than a new one. On reconfiguration, we flush the buffers (if any).
+    In all other cases we return the enabled status without reconfiguration.
 
     :param endpoint: Telemetry endpoint to send data. If not given,
     default endpoint is used.
diff --git a/exasol/telemetry/client/worker.py b/exasol/telemetry/client/worker.py
index ea0336d..a00644a 100644
--- a/exasol/telemetry/client/worker.py
+++ b/exasol/telemetry/client/worker.py
@@ -310,5 +310,8 @@ def track(
 
     global _queue
     if _queue is not None:
-        if _queue.not_full:
-            _queue.put(WorkerMessage.make_track(product_name, product_version, feature))
+        try:
+            msg = WorkerMessage.make_track(product_name, product_version, feature)
+            _queue.put_nowait(msg)
+        except queue.Full:
+            pass

From d4b3e9330f37e82795898e1f67f81335d89509fa Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Tue, 29 Sep 2026 15:44:24 +0200
Subject: [PATCH 09/15] Extra test

---
 test/unit/client/test_worker.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/unit/client/test_worker.py b/test/unit/client/test_worker.py
index 3ad5d77..8cca630 100644
--- a/test/unit/client/test_worker.py
+++ b/test/unit/client/test_worker.py
@@ -97,6 +97,24 @@ def test_worker_proc_sent_quick(
     mock_post.assert_called_once()
 
 
+# Make sure that buffers are sent after reconfiguration
+@mock.patch("requests.post", return_value=mock.MagicMock(status_code=200))
+def test_worker_proc_sent_after_disable(
+    mock_post: mock.MagicMock,
+    telemetry_reset,
+    telemetry_unset_ci,
+    telemetry_unset_disable,
+):
+    # enable and send track feature
+    assert setup(disable=False)
+    track("product", "ver", "test")
+    # after reconfiguration we should be disabled and flushed the buffers
+    assert not setup(disable=True)
+    mock_post.assert_called_once()
+    assert config.was_setup()
+    assert not config.was_enabled()
+
+
 # Make sure that features are not sent if not enabled
 @mock.patch("requests.post")
 def test_worker_proc_not_sent_when_disabled(

From d617d627a8c777164b8188641c6f3a6ce29e3df1 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Wed, 30 Sep 2026 05:54:10 +0200
Subject: [PATCH 10/15] Test on blocked worker

---
 test/unit/client/test_worker.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/test/unit/client/test_worker.py b/test/unit/client/test_worker.py
index 8cca630..607914f 100644
--- a/test/unit/client/test_worker.py
+++ b/test/unit/client/test_worker.py
@@ -2,6 +2,8 @@
 import time
 from unittest import mock
 
+from more_itertools.more import side_effect
+
 from exasol.telemetry.client import *
 from exasol.telemetry.client import (
     config,
@@ -132,6 +134,19 @@ def test_worker_proc_not_sent_when_disabled(
     mock_post.assert_not_called()
 
 
+@mock.patch("requests.post", side_effect=lambda *w, **kw: time.sleep(1000))
+def test_shutdown_exits_on_blocked_worker(
+        mock_post: mock.MagicMock,
+        telemetry_reset,
+        telemetry_unset_ci,
+        telemetry_unset_disable,
+):
+    assert setup(disable=False)
+    track("test", "0.1", "test-feature")
+    shutdown(flush_buffers=True)
+    mock_post.assert_called_once()
+
+
 @mock.patch("exasol.telemetry.client.worker.send_features")
 def test_worker_proc_no_send(mock_send_features: mock.MagicMock):
     msg_queue = queue.Queue()

From 62cbb668f8843eeb001dfbda078bc5f400a31343 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Wed, 30 Sep 2026 05:55:14 +0200
Subject: [PATCH 11/15] Format

---
 test/unit/client/test_worker.py | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/test/unit/client/test_worker.py b/test/unit/client/test_worker.py
index 607914f..abd34b0 100644
--- a/test/unit/client/test_worker.py
+++ b/test/unit/client/test_worker.py
@@ -2,8 +2,6 @@
 import time
 from unittest import mock
 
-from more_itertools.more import side_effect
-
 from exasol.telemetry.client import *
 from exasol.telemetry.client import (
     config,
@@ -136,10 +134,10 @@ def test_worker_proc_not_sent_when_disabled(
 
 @mock.patch("requests.post", side_effect=lambda *w, **kw: time.sleep(1000))
 def test_shutdown_exits_on_blocked_worker(
-        mock_post: mock.MagicMock,
-        telemetry_reset,
-        telemetry_unset_ci,
-        telemetry_unset_disable,
+    mock_post: mock.MagicMock,
+    telemetry_reset,
+    telemetry_unset_ci,
+    telemetry_unset_disable,
 ):
     assert setup(disable=False)
     track("test", "0.1", "test-feature")

From 2c1cc77ada6418f955eeb83b98f8028f97b95d97 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Wed, 30 Sep 2026 14:19:12 +0200
Subject: [PATCH 12/15] Handle full queue on shutdown

---
 exasol/telemetry/client/worker.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/exasol/telemetry/client/worker.py b/exasol/telemetry/client/worker.py
index a00644a..28b7e94 100644
--- a/exasol/telemetry/client/worker.py
+++ b/exasol/telemetry/client/worker.py
@@ -268,6 +268,8 @@ def start_worker() -> bool:
 def stop_worker(flush_buffers: bool):
     """
     Gracefully stops the worker process.
+
+    In case of connectivity issues, flush of buffers might not happen.
     :param flush_buffers: if True, we'll try to send the buffers (if any),
     otherwise, we'll just shut down the worker process.
     """
@@ -277,8 +279,15 @@ def stop_worker(flush_buffers: bool):
         return
     if flush_buffers:
         _queue.put(WorkerMessage.make_send_buffers())
-    _queue.put(WorkerMessage.make_terminate())
-    _worker.join(timeout=THREAD_EXIT_TIMEOUT_SECONDS)
+    try:
+        _queue.put_nowait(WorkerMessage.make_terminate())
+        _worker.join(timeout=THREAD_EXIT_TIMEOUT_SECONDS)
+    except queue.Full:
+        # rare situation - if the thread is blocked on send and
+        # we have lots of messages in the queue, we can have no capacity
+        # in the queue. In such cases, we just don't stop the thread,
+        # which is fine as thread is daemon.
+        pass
     _worker = None
     _queue = None
 

From d505950236fcd843e3ebb772902fe1021abf49e7 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Wed, 30 Sep 2026 14:21:21 +0200
Subject: [PATCH 13/15] Update docstring

---
 exasol/telemetry/client/config.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/exasol/telemetry/client/config.py b/exasol/telemetry/client/config.py
index dc18595..0f3598f 100644
--- a/exasol/telemetry/client/config.py
+++ b/exasol/telemetry/client/config.py
@@ -56,6 +56,7 @@ def was_enabled() -> bool:
 def disable_config():
     """
     Call disables telemetry entirely for all subsequent calls.
+    Telemetry still might be re-enabled by call to setup() with the opposite disable flag.
     """
     conf = Config(enabled=False, endpoint=DEFAULT_ENDPOINT)
     store(conf)

From c83aa27cc45596d39114fed0914cbddc0d9ab124 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Wed, 30 Sep 2026 14:21:57 +0200
Subject: [PATCH 14/15] Update release date

---
 doc/changes/changes_0.2.1.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/changes/changes_0.2.1.md b/doc/changes/changes_0.2.1.md
index 8b94bbc..c25c25f 100644
--- a/doc/changes/changes_0.2.1.md
+++ b/doc/changes/changes_0.2.1.md
@@ -1,4 +1,4 @@
-# 0.2.1 - 2026-09-29
+# 0.2.1 - 2026-09-30
 
 ## Summary
 

From e387f8a28355cb3cd53068ff5269a057558ec805 Mon Sep 17 00:00:00 2001
From: Maxim Lapan <maxim.lapan@exasol.com>
Date: Thu, 1 Oct 2026 07:53:12 +0200
Subject: [PATCH 15/15] Make flush of buffers non-blocking

---
 exasol/telemetry/client/worker.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/exasol/telemetry/client/worker.py b/exasol/telemetry/client/worker.py
index 28b7e94..e39f67e 100644
--- a/exasol/telemetry/client/worker.py
+++ b/exasol/telemetry/client/worker.py
@@ -277,9 +277,9 @@ def stop_worker(flush_buffers: bool):
 
     if _worker is None or _queue is None:
         return
-    if flush_buffers:
-        _queue.put(WorkerMessage.make_send_buffers())
     try:
+        if flush_buffers:
+            _queue.put_nowait(WorkerMessage.make_send_buffers())
         _queue.put_nowait(WorkerMessage.make_terminate())
         _worker.join(timeout=THREAD_EXIT_TIMEOUT_SECONDS)
     except queue.Full: