Merge ~martin-hilton/charm-prometheus2:001-fix-storage-arguments into ~prometheus-charmers/charm-prometheus2:master

[Martin Hilton]

Fix error with specifying the "storage.tsdb.path" flag twice when using juju storage.

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

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

[Thomas Cuthbert (tcuthbert)]

LGTM +1
I noticed that the storage path argument is different, did a bit of investigation and worked out that the command in 1.8 is actually different to `--storage.tsdb.path` so I am a little perplexed how this worked in the first place...

review: Approve

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

Change successfully merged at revision e36aecf7c383892bc6d8f0ce06b78f71104b57a8

diff --git a/reactive/prometheus.py b/reactive/prometheus.py
index 2f686b7..3085b2a 100644
--- a/reactive/prometheus.py
+++ b/reactive/prometheus.py
@@ -156,13 +156,12 @@ def get_rule_files():
 
 
 # TODO: once there's reactive support for storage hooks, convert off @hook()
-@hook('metrics-{filesystem,block}-storage-attached')
+@hook('metrics-filesystem-storage-attached')
 def configure_storage():
     storage_path = subprocess.check_output(
         ['storage-get', 'location']).decode().strip()
     kv = unitdata.kv()
     kv.set('storage-path', storage_path)
-    runtime_args('--storage.tsdb.path', storage_path)
     set_state('storage.configured')
     set_state('prometheus.do-check-reconfig')