Add enable_web_admin_api config to prometheus charm

Unit tests fixed

Change-Id: I8400794918780f929ad7612f72d477d37aee1b74
Signed-off-by: David Garcia <david.garcia@canonical.com>
diff --git a/installers/charm/prometheus/src/pod_spec.py b/installers/charm/prometheus/src/pod_spec.py
index 541cf3e..202114e 100644
--- a/installers/charm/prometheus/src/pod_spec.py
+++ b/installers/charm/prometheus/src/pod_spec.py
@@ -95,6 +95,7 @@
         "tls_secret_name": lambda value, _: isinstance(value, str)
         if value is not None
         else True,
+        "enable_web_admin_api": lambda value, _: isinstance(value, bool),
     }
     relation_validators = {}
     problems = []
@@ -307,9 +308,7 @@
     Returns:
         List[str]: command to startup the process.
     """
-    return [
-        "sh",
-        "-c",
+    command = [
         "/bin/prometheus",
         "--config.file=/etc/prometheus/prometheus.yml",
         "--storage.tsdb.path=/prometheus",
@@ -320,6 +319,9 @@
             port, config.get("web_subpath")
         ),
     ]
+    if config.get("enable_web_admin_api"):
+        command.append("--web.enable-admin-api")
+    return command
 
 
 def make_pod_spec(