From b02bc9dc094cae2d9a02f72e3d69d4db1227a3ed Mon Sep 17 00:00:00 2001
From: Chris Larsen <clarsen@netflix.com>
Date: Fri, 20 Sep 2024 12:10:59 -0700
Subject: [PATCH] chart: add default theme to JsonCodec parsing. (#1693)

The old scala 2.12 code did not serialize the theme in the v2.json graph metadata. For Core,
they're using Spark to emit data in V2 then parsing it with the latest Atlas code. This will
fix the issue for them.
---
 .../com/netflix/atlas/chart/JsonCodec.scala   |  3 +-
 .../netflix/atlas/chart/JsonCodecSuite.scala  | 45 +++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/atlas-chart/src/main/scala/com/netflix/atlas/chart/JsonCodec.scala b/atlas-chart/src/main/scala/com/netflix/atlas/chart/JsonCodec.scala
index bcec322b1..5ac912540 100644
--- a/atlas-chart/src/main/scala/com/netflix/atlas/chart/JsonCodec.scala
+++ b/atlas-chart/src/main/scala/com/netflix/atlas/chart/JsonCodec.scala
@@ -25,6 +25,7 @@ import com.fasterxml.jackson.core.JsonGenerator
 import com.fasterxml.jackson.core.JsonParser
 import com.fasterxml.jackson.databind.JsonNode
 import com.fasterxml.jackson.databind.ObjectMapper
+import com.netflix.atlas.chart.graphics.ChartSettings
 import com.netflix.atlas.chart.model.*
 import com.netflix.atlas.chart.util.PngImage
 import com.netflix.atlas.core.model.ArrayTimeSeq
@@ -423,7 +424,7 @@ object JsonCodec {
       loadTime       = Option(node.get("loadTime")).fold(-1L)(_.asLong()),
       stats          = Option(node.get("stats")).fold(CollectorStats.unknown)(toCollectorStats),
       warnings       = node.get("warnings").elements.asScala.map(_.asText()).toList,
-      themeName      = node.get("theme").asText(),
+      themeName      = Option(node.get("theme")).fold(ChartSettings.defaultTheme)(_.asText()),
       renderingHints = processRenderingHints(node.get("renderingHints"))
     )
     // format: on
diff --git a/atlas-chart/src/test/scala/com/netflix/atlas/chart/JsonCodecSuite.scala b/atlas-chart/src/test/scala/com/netflix/atlas/chart/JsonCodecSuite.scala
index 38bcb86cf..d573999d2 100644
--- a/atlas-chart/src/test/scala/com/netflix/atlas/chart/JsonCodecSuite.scala
+++ b/atlas-chart/src/test/scala/com/netflix/atlas/chart/JsonCodecSuite.scala
@@ -16,12 +16,15 @@
 package com.netflix.atlas.chart
 
 import com.netflix.atlas.chart.model.GraphDef
+import com.netflix.atlas.chart.model.Layout
 import com.netflix.atlas.chart.model.LineDef
 import com.netflix.atlas.chart.model.PlotDef
 import com.netflix.atlas.core.model.TimeSeries
 import munit.FunSuite
 
+import java.io.ByteArrayInputStream
 import java.time.Instant
+import java.time.ZoneId
 
 class JsonCodecSuite extends FunSuite {
 
@@ -35,9 +38,51 @@ class JsonCodecSuite extends FunSuite {
     )
   }
 
+  private def fromJson(json: String): GraphDef = {
+    JsonCodec.decode(new ByteArrayInputStream(json.getBytes("UTF-8")))
+  }
+
+  test("decode - graph-metadata: required only") {
+    val json =
+      """
+        |[
+        |    {
+        |        "type": "graph-metadata",
+        |        "startTime": 0,
+        |        "endTime": 60000,
+        |        "timezones": [
+        |            "Z"
+        |        ],
+        |        "step": 60000,
+        |        "width": 400,
+        |        "height": 200,
+        |        "layout": "CANVAS",
+        |        "zoom": 1,
+        |        "legendType": "LABELS_WITH_STATS",
+        |        "onlyGraph": false,
+        |        "warnings": []
+        |    }
+        |]
+        |""".stripMargin
+    val gdef = fromJson(json)
+    assertEquals(gdef.startTime.toEpochMilli, 0L)
+    assertEquals(gdef.endTime.toEpochMilli, 60_000L)
+    assertEquals(gdef.timezones, List(ZoneId.of("Z")))
+    assertEquals(gdef.step, 60_000L)
+    assertEquals(gdef.width, 400)
+    assertEquals(gdef.height, 200)
+    assertEquals(gdef.layout, Layout.CANVAS)
+    assertEquals(gdef.zoom, 1.0)
+    assertEquals(gdef.legendType.toString, "LABELS_WITH_STATS")
+    assertEquals(gdef.onlyGraph, false)
+    assertEquals(gdef.warnings, List.empty)
+    assertEquals(gdef.themeName, "light")
+  }
+
   test("rendering hint: none") {
     val gdef = graphDef(Set.empty)
     val str = JsonCodec.encode(gdef)
+    System.out.println(str)
     assert(str.contains(""""type":"graph-image""""))
   }