L2SS-1054: add loki datasource

Closes L2SS-1054

dashboards/logs.json

+{
+    "annotations": {
+      "list": [
+        {
+          "builtIn": 1,
+          "datasource": {
+            "type": "grafana",
+            "uid": "-- Grafana --"
+          },
+          "enable": true,
+          "hide": true,
+          "iconColor": "rgba(0, 211, 255, 1)",
+          "name": "Annotations & Alerts",
+          "target": {
+            "limit": 100,
+            "matchAny": false,
+            "tags": [],
+            "type": "dashboard"
+          },
+          "type": "dashboard"
+        }
+      ]
+    },
+    "editable": true,
+    "fiscalYearStartMonth": 0,
+    "graphTooltip": 0,
+    "id": null,
+    "links": [],
+    "liveNow": false,
+    "panels": [
+      {
+        "datasource": {
+          "type": "loki",
+          "uid": "loki"
+        },
+        "fieldConfig": {
+          "defaults": {
+            "color": {
+              "mode": "palette-classic"
+            },
+            "custom": {
+              "axisCenteredZero": false,
+              "axisColorMode": "text",
+              "axisLabel": "",
+              "axisPlacement": "auto",
+              "fillOpacity": 80,
+              "gradientMode": "none",
+              "hideFrom": {
+                "legend": false,
+                "tooltip": false,
+                "viz": false
+              },
+              "lineWidth": 1,
+              "scaleDistribution": {
+                "type": "linear"
+              },
+              "thresholdsStyle": {
+                "mode": "off"
+              }
+            },
+            "mappings": [],
+            "thresholds": {
+              "mode": "absolute",
+              "steps": [
+                {
+                  "color": "green",
+                  "value": null
+                },
+                {
+                  "color": "red",
+                  "value": 80
+                }
+              ]
+            }
+          },
+          "overrides": [
+            {
+              "matcher": {
+                "id": "byName",
+                "options": "DEBUG"
+              },
+              "properties": [
+                {
+                  "id": "color",
+                  "value": {
+                    "fixedColor": "blue",
+                    "mode": "fixed"
+                  }
+                }
+              ]
+            },
+            {
+              "matcher": {
+                "id": "byName",
+                "options": "ERROR"
+              },
+              "properties": [
+                {
+                  "id": "color",
+                  "value": {
+                    "fixedColor": "red",
+                    "mode": "fixed"
+                  }
+                }
+              ]
+            },
+            {
+              "matcher": {
+                "id": "byName",
+                "options": "INFO"
+              },
+              "properties": [
+                {
+                  "id": "color",
+                  "value": {
+                    "fixedColor": "green",
+                    "mode": "fixed"
+                  }
+                }
+              ]
+            },
+            {
+              "matcher": {
+                "id": "byName",
+                "options": "WARNING"
+              },
+              "properties": [
+                {
+                  "id": "color",
+                  "value": {
+                    "fixedColor": "yellow",
+                    "mode": "fixed"
+                  }
+                }
+              ]
+            }
+          ]
+        },
+        "gridPos": {
+          "h": 9,
+          "w": 24,
+          "x": 0,
+          "y": 0
+        },
+        "id": 3,
+        "options": {
+          "barRadius": 0,
+          "barWidth": 0.5,
+          "groupWidth": 0.7,
+          "legend": {
+            "calcs": [],
+            "displayMode": "list",
+            "placement": "bottom",
+            "showLegend": false
+          },
+          "orientation": "auto",
+          "showValue": "never",
+          "stacking": "normal",
+          "tooltip": {
+            "mode": "single",
+            "sort": "none"
+          },
+          "xTickLabelRotation": 0,
+          "xTickLabelSpacing": 0
+        },
+        "pluginVersion": "9.3.0-beta1",
+        "targets": [
+          {
+            "datasource": {
+              "type": "loki",
+              "uid": "loki"
+            },
+            "editorMode": "code",
+            "expr": "rate({program=\"/home/tango/.local/bin/l2ss-$device\"} [$__interval])",
+            "hide": false,
+            "legendFormat": "{{level}}",
+            "queryType": "range",
+            "refId": "A",
+            "resolution": 1
+          }
+        ],
+        "title": "Log Volume",
+        "type": "barchart"
+      },
+      {
+        "datasource": {
+          "type": "loki",
+          "uid": "loki"
+        },
+        "gridPos": {
+          "h": 9,
+          "w": 24,
+          "x": 0,
+          "y": 9
+        },
+        "id": 1,
+        "options": {
+          "dedupStrategy": "none",
+          "enableLogDetails": true,
+          "prettifyLogMessage": false,
+          "showCommonLabels": false,
+          "showLabels": false,
+          "showTime": true,
+          "sortOrder": "Descending",
+          "wrapLogMessage": false
+        },
+        "targets": [
+          {
+            "datasource": {
+              "type": "loki",
+              "uid": "loki"
+            },
+            "editorMode": "code",
+            "expr": "{program=\"/home/tango/.local/bin/l2ss-$device\"} |= `` | logfmt",
+            "key": "Q-9ba51526-d461-4190-a861-0ca3403910d3-0",
+            "queryType": "range",
+            "refId": "A"
+          }
+        ],
+        "title": "Device Log",
+        "transformations": [
+          {
+            "id": "filterFieldsByName",
+            "options": {}
+          }
+        ],
+        "type": "logs"
+      }
+    ],
+    "refresh": "",
+    "schemaVersion": 37,
+    "style": "dark",
+    "tags": [],
+    "templating": {
+      "list": [
+        {
+          "current": {},
+          "definition": "scrape_series_added",
+          "hide": 0,
+          "includeAll": false,
+          "label": "Station",
+          "multi": false,
+          "name": "station",
+          "options": [],
+          "query": {
+            "query": "scrape_series_added",
+            "refId": "StandardVariableQuery"
+          },
+          "refresh": 1,
+          "regex": "/.*host=\"(?<text>[^\"]*)\".*/",
+          "skipUrlSync": false,
+          "sort": 1,
+          "type": "query"
+        },
+        {
+          "current": {},
+          "definition": "device_scraping{host=\"$station\", device=~\"stat/.*/1\"}",
+          "hide": 0,
+          "includeAll": false,
+          "label": "Device",
+          "multi": false,
+          "name": "device",
+          "options": [],
+          "query": {
+            "query": "device_scraping{host=\"$station\", device=~\"stat/.*/1\"}",
+            "refId": "StandardVariableQuery"
+          },
+          "refresh": 1,
+          "regex": "/.*device=\"stat/(?<text>[^\"]*)/1\".*/",
+          "skipUrlSync": false,
+          "sort": 1,
+          "type": "query"
+        }
+      ]
+    },
+    "time": {
+      "from": "now-1h",
+      "to": "now"
+    },
+    "timepicker": {},
+    "timezone": "",
+    "title": "Logs",
+    "uid": "Hqo-qIO4z",
+    "version": 15,
+    "weekStart": ""
+  }