add wrapper class (#25)

* add wrapper class

* format wrapper file

Author: luuisabelle

grafana/provisioning/dashboards/wrapper.py

@@ -0,0 +1,74 @@
+from dataclasses import dataclass
+from typing import Optional, Final
+
+from grafanalib.core import Row, Dashboard, Target, TimeSeries, GridPos
+
+from common import PROMETHEUS_DATASOURCE_NAME
+
+
+class RefIdGenerator:
+    STARTING_CHAR_INTEGER = ord("A")
+
+    def __init__(self):
+        self.offset = 0
+
+    def next(self) -> str:
+        result = chr(self.STARTING_CHAR_INTEGER + self.offset)
+        self.offset += 1
+        return result
+
+
+@dataclass
+class ExpressionAndLegendPair:
+    expression: str
+    legend: Optional[str] = None
+
+
+class SceGrafanalibWrapper:
+    MAX_WIDTH: Final[int] = 24
+
+    def __init__(self, title, panel_width=12, panel_height=8):
+        self.rows = []
+        self.panels = []
+        self.title = title
+        self.current_x = 0
+        self.current_y = 0
+        self.panel_width = min(panel_width, self.MAX_WIDTH)
+        self.panel_height = panel_height
+
+    def AddPanel(self, title, queries: list[ExpressionAndLegendPair]):
+        targets = []
+        iterator = RefIdGenerator()
+        for query in queries:
+            query_text = query.expression
+            query_label = query.legend
+            refId = iterator.next()
+            targets.append(
+                Target(
+                    expr=query_text,
+                    legendFormat=query_label,
+                    refId=refId,
+                    datasource=PROMETHEUS_DATASOURCE_NAME,
+                )
+            )
+        self.panels.append(
+            TimeSeries(
+                title=title,
+                targets=targets,
+                gridPos=GridPos(
+                    h=self.panel_height,
+                    w=self.panel_width,
+                    x=self.current_x,
+                    y=self.current_y,
+                ),
+            )
+        )
+        self.current_x += self.panel_width
+        if self.current_x >= self.MAX_WIDTH / 2:
+            self.current_y += self.panel_height
+            self.current_x = 0
+
+    def Render(self):
+        return Dashboard(
+            title=self.title, rows=self.rows, panels=self.panels
+        ).auto_panel_ids()