add loki role and fix linter errors

roles/loki/templates/loki.service.j2

@@ -0,0 +1,11 @@
+[Unit]
+Description=Loki service
+After=network.target
+
+[Service]
+Type=simple
+User=root
+ExecStart=/opt/loki/loki -config.file /etc/loki/loki.yml
+
+[Install]
+WantedBy=multi-user.target

roles/loki/templates/loki.yml.j2

@@ -0,0 +1,83 @@
+auth_enabled: false
+
+server:
+  http_listen_port: {{ loki_port }}
+  # grpc_listen_port: 9096
+  # log_level: debug
+  # grpc_server_max_concurrent_streams: 1000
+
+common:
+  instance_addr: 127.0.0.1
+  path_prefix: {{ loki_storage_path }}
+  storage:
+    filesystem:
+      chunks_directory: {{ loki_storage_path }}/chunks
+      rules_directory: {{ loki_storage_path }}/rules
+  replication_factor: 1
+  ring:
+    kvstore:
+      store: inmemory
+
+# ingester:
+#   lifecycler:
+#     address: 127.0.0.1
+#     ring:
+#       kvstore:
+#         store: inmemory
+#       replication_factor: 1
+#     final_sleep: 0s
+#   chunk_idle_period: 5m
+#   chunk_retain_period: 30s
+#   max_transfer_retries: 0
+
+schema_config:
+  configs:
+    - from: 2020-10-24
+      store: tsdb
+      object_store: filesystem
+      schema: v13
+      index:
+        prefix: index_
+        period: 24h
+
+pattern_ingester:
+  enabled: true
+  metric_aggregation:
+    loki_address: localhost:3100
+
+# storage_config:
+#   boltdb:
+#     directory: {{ loki_storage_path }}/index
+
+#   filesystem:
+#     directory: {{ loki_storage_path }}/chunks
+
+# ruler:
+#   alertmanager_url: http://localhost:9093
+
+query_range:
+  results_cache:
+    cache:
+      embedded_cache:
+        enabled: true
+        max_size_mb: 100
+
+frontend:
+  encoding: protobuf
+
+# querier:
+#   engine:
+#     enable_multi_variant_queries: true
+
+limits_config:
+  metric_aggregation_enabled: true
+
+# chunk_store_config:
+#   max_look_back_period: 0s
+
+# table_manager:
+#   retention_deletes_enabled: false
+#   retention_period: 0s
+
+analytics:
+  reporting_enabled: false

roles/loki/templates/loki_test.yml.j2

@@ -0,0 +1,45 @@
+auth_enabled: false
+
+server:
+  http_listen_port: 3200
+
+ingester:
+  lifecycler:
+    address: 127.0.0.1
+    ring:
+      kvstore:
+        store: inmemory
+      replication_factor: 1
+    final_sleep: 0s
+  chunk_idle_period: 5m
+  chunk_retain_period: 30s
+  max_transfer_retries: 0
+
+schema_config:
+  configs:
+    - from: 2018-04-15
+      store: boltdb
+      object_store: filesystem
+      schema: v11
+      index:
+        prefix: index_
+        period: 168h
+
+storage_config:
+  boltdb:
+    directory: /data/loki/index
+
+  filesystem:
+    directory: /data/loki/chunks
+
+limits_config:
+  enforce_metric_name: false
+  reject_old_samples: true
+  reject_old_samples_max_age: 168h
+
+chunk_store_config:
+  max_look_back_period: 0s
+
+table_manager:
+  retention_deletes_enabled: false
+  retention_period: 0s