loki: Run Grafana Loki in a container

Deploying Loki is pretty straightforward.  It just needs a container
unit file and a basic YAML configuration file.

app/loki/templates.cue

@@ -0,0 +1,26 @@
+package loki
+
+import "du5t1n.me/cfg/base/schema/instructions"
+
+templates: [...instructions.#RenderInstruction] & [
+	{
+		template: "loki/config.yml"
+		dest:     "/etc/loki/config.yml"
+		hooks: {
+			changed: [{run: "systemctl try-restart loki"}]
+		}
+	},
+	{
+		template: "loki/loki.container"
+		dest:     "/etc/containers/systemd/loki.container"
+		hooks: {
+			changed: [
+				{
+					run:       "systemctl daemon-reload"
+					immediate: true
+				},
+				{run: "systemctl restart loki"},
+			]
+		}
+	},
+]

instructions/loki0.pyrocufflink.blue.cue

@@ -2,10 +2,12 @@ import (
 	"list"
 
 	"du5t1n.me/cfg/app/collectd"
+	"du5t1n.me/cfg/app/loki"
 	"du5t1n.me/cfg/env/prod"
 )
 
 render: list.Concat([
 	collectd.templates,
+	loki.templates,
 	prod.templates,
 ])

templates/loki/config.yml

@@ -0,0 +1,37 @@
+auth_enabled: false
+
+server:
+  http_listen_port: 3100
+  grpc_listen_port: 9096
+
+common:
+  instance_addr: 127.0.0.1
+  path_prefix: /var/lib/loki
+  storage:
+    filesystem:
+      chunks_directory: /var/lib/loki/chunks
+      rules_directory: /var/lib/loki/rules
+  replication_factor: 1
+  ring:
+    kvstore:
+      store: inmemory
+
+query_range:
+  results_cache:
+    cache:
+      embedded_cache:
+        enabled: true
+        max_size_mb: 100
+
+schema_config:
+  configs:
+  - from: 2020-10-24
+    store: tsdb
+    object_store: filesystem
+    schema: v12
+    index:
+      prefix: index_
+      period: 24h
+
+query_scheduler:
+  max_outstanding_requests_per_tenant: 1024

templates/loki/loki.container

@@ -0,0 +1,18 @@
+# vim: set ft=systemd :
+[Unit]
+Description=Grafana Loki
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+StateDirectory=%P
+
+[Container]
+Image=docker.io/grafana/loki:2.9.4
+Exec=-config.file=/etc/loki/config.yml
+Volume=%S/%P:/var/lib/loki:rw,Z,U
+Volume=/etc/loki:/etc/loki:ro
+PublishPort=3100:3100
+
+[Install]
+WantedBy=multi-user.target