Merge ~sajoupa/charm-telegraf:snap_daemon_user into charm-telegraf:master

[Laurent Sesquès]

when using the snap, set config files ownership to snap_daemon https://snapcraft.io/docs/services-and-daemons

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[Laurent Sesquès (sajoupa)]

passes make test (without bionic-compute and focal-compute, which kill my machine)

[Laurent Sesquès (sajoupa)]

(also, a couple of fixes for black / make lint)

[Benjamin Allot (ballot)]

LGTM

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 6ef444a43da988a0b48fc24d3acde8ad1c348bb5

diff --git a/src/reactive/telegraf.py b/src/reactive/telegraf.py
index 017ad67..d8fd268 100644
--- a/src/reactive/telegraf.py
+++ b/src/reactive/telegraf.py
@@ -72,6 +72,11 @@ GRAFANA_DASHBOARD_NAME = "telegraf"
 SNAP_SERVICE = "snap.telegraf.telegraf"
 DEB_SERVICE = "telegraf"
 
+SNAP_USER = "snap_daemon"
+SNAP_GROUP = "snap_daemon"
+DEB_USER = "root"
+DEB_GROUP = "telegraf"
+
 # Utilities #
 
 
@@ -83,7 +88,8 @@ def write_telegraf_file(path, content):
     return host.write_file(
         path,
         content.encode("UTF-8"),
-        group="telegraf",
+        owner=get_telegraf_user(),
+        group=get_telegraf_group(),
         perms=0o640,
     )
 
@@ -101,6 +107,24 @@ def get_install_method():
         raise InvalidInstallMethod()
 
 
+def get_telegraf_user():
+    install_method = get_install_method()
+
+    # get_install_method() already checked that we got a valid value
+    if install_method == "snap":
+        return SNAP_USER
+    return DEB_USER
+
+
+def get_telegraf_group():
+    install_method = get_install_method()
+
+    # get_install_method() already checked that we got a valid value
+    if install_method == "snap":
+        return SNAP_GROUP
+    return DEB_GROUP
+
+
 def get_base_dir():
     config = hookenv.config()
 
diff --git a/src/tests/functional/tests/base.py b/src/tests/functional/tests/base.py
index 3433c5d..23dedab 100644
--- a/src/tests/functional/tests/base.py
+++ b/src/tests/functional/tests/base.py
@@ -32,8 +32,10 @@ class BaseTelegrafTest(unittest.TestCase):
     def check_re_pattern(self, re_pattern, text):
         logging.info("checking metrics %s", re_pattern)
         # findall returns a list, [] when no match
-        self.assertTrue(re.findall(re_pattern, text, flags=re.M),
-                        msg="Failed to find {}".format(re_pattern))
+        self.assertTrue(
+            re.findall(re_pattern, text, flags=re.M),
+            msg="Failed to find {}".format(re_pattern),
+        )
 
     def check_metrics(self, patterns):
         principal_units = (
diff --git a/src/tests/functional/tests/test_compute.py b/src/tests/functional/tests/test_compute.py
index db4f3b9..450205f 100644
--- a/src/tests/functional/tests/test_compute.py
+++ b/src/tests/functional/tests/test_compute.py
@@ -43,7 +43,7 @@ class TestTelegrafCompute(BaseTelegrafTest):
         # Sometimes, the logs show errors on Telegraf first start because br-int isn't
         # yet started.  To overcome this, just check the most recent start of Telegraf.
         up_to_word = "I! Starting Telegraf"
-        rx_to_last = r'^.*{}'.format(re.escape(up_to_word))
+        rx_to_last = r"^.*{}".format(re.escape(up_to_word))
         last_logs = re.sub(rx_to_last, "", content, flags=re.DOTALL).strip()
         error_pattern = "E!"
         self.assertFalse(re.findall(error_pattern, last_logs, flags=re.M))
diff --git a/src/tests/unit/test_telegraf.py b/src/tests/unit/test_telegraf.py
index 7179db6..62a5595 100644
--- a/src/tests/unit/test_telegraf.py
+++ b/src/tests/unit/test_telegraf.py
@@ -190,15 +190,27 @@ def check_sysstat_config(original, expected):
     assert actual == expected
 
 
-def test_write_telegraf_file(mocker):
+def test_write_telegraf_file(mocker, config):
+    config["install_method"] = "deb"
     write_file = mocker.patch("charmhelpers.core.host.write_file")
     telegraf.write_telegraf_file("the-path", "the-content áéíóú")
     write_file.assert_called_once_with(
         "the-path",
         "the-content áéíóú".encode("utf-8"),
+        owner="root",
         group="telegraf",
         perms=0o640,
     )
+    config["install_method"] = "snap"
+    write_file = mocker.patch("charmhelpers.core.host.write_file")
+    telegraf.write_telegraf_file("the-path", "the-content áéíóú")
+    write_file.assert_called_once_with(
+        "the-path",
+        "the-content áéíóú".encode("utf-8"),
+        owner="snap_daemon",
+        group="snap_daemon",
+        perms=0o640,
+    )
 
 
 def test_sadc_options_correct(monkeypatch):