add Graphite metric provider documentation

Signed-off-by: Mike Ball <[email protected]>

docs/analysis/graphite.md

@@ -0,0 +1,35 @@
+# Graphite Metrics
+
+A [Graphite](https://graphiteapp.org/) query can be used to obtain measurements for analysis.
+
+```yaml
+apiVersion: argoproj.io/v1alpha1
+kind: AnalysisTemplate
+metadata:
+  name: success-rate
+spec:
+  args:
+  - name: service-name
+  metrics:
+  - name: success-rate
+    interval: 5m
+    # Note that the Argo Rollouts Graphite metrics provider returns results as float64s with 6 decimal places.
+    successCondition: result >= 90.000000
+    failureLimit: 3
+    provider:
+      graphite:
+        address: http://graphite.example.com:9090
+        query: |
+          target=summarize(
+            asPercent(
+              sumSeries(
+                stats.timers.httpServerRequests.app.{{args.service-name}}.exception.*.method.*.outcome.{CLIENT_ERROR,INFORMATIONAL,REDIRECTION,SUCCESS}.status.*.uri.*.count
+              ),
+              sumSeries(
+                stats.timers.httpServerRequests.app.{{args.service-name}}.exception.*.method.*.outcome.*.status.*.uri.*.count
+              )
+            ),
+            '5min',
+            'avg'
+          )
+```

docs/index.md

@@ -29,7 +29,7 @@ For these reasons, in large scale high-volume production environments, a rolling
 * Customizable metric queries and analysis of business KPIs
 * Ingress controller integration: NGINX, ALB
 * Service Mesh integration: Istio, Linkerd, SMI
-* Metric provider integration: Prometheus, Wavefront, Kayenta, Web, Kubernetes Jobs, Datadog, New Relic
+* Metric provider integration: Prometheus, Wavefront, Kayenta, Web, Kubernetes Jobs, Datadog, New Relic, Graphite
 
 ## Quick Start