feat: nsq scaler docs

Signed-off-by: Matt Ulmer <[email protected]>

.htmltest.yml

@@ -5,7 +5,7 @@ IgnoreAltMissing: true
 IgnoreEmptyHref: true
 IgnoreInternalURLs:
   # Temporal ignores
-
+  - /docs/2.15/scalers/nsq/
   # Deprecated and removed resources
   - /docs/2.15/authentication-providers/azure-ad-pod-identity/
   - /docs/2.15/authentication-providers/aws-kiam/

content/docs/2.16/scalers/nsq.md

@@ -0,0 +1,55 @@
++++
+title = "NSQ"
+availability = "v2.16+"
+maintainer = "Community"
+category = "Messaging"
+description = "Scale applications based on NSQ topic/channel depth."
+go_file = "nsq_scaler"
++++
+
+### Trigger Specification
+
+This specification describes the `nsq` trigger that scales based on [NSQ](https://github.com/nsqio/nsq) topic/channel depth. 
+
+```yaml
+triggers:
+- type: nsq
+  metadata:
+    nsqLookupdHTTPAddresses: "nsq-nsqlookupd.nsq:4161"
+    topic: "example_topic"
+    channel: "example_channel"
+    depthThreshold: "10"
+    activationDepthThreshold: "0"
+```
+
+**Parameter list:**
+
+- `nsqLookupdHTTPAddresses` - Comma separated list of [nsqlookupd](https://nsq.io/components/nsqlookupd.html) HTTP addresses in the form `<hostname>:<port>`.
+- `topic` - Name of the NSQ datastream that the `channel` relates to.
+- `channel` - Name of the channel used to calculate depth.
+- `depthThreshold` - Target value for depth to trigger scaling actions. (Default `10`, Optional)
+- `activationDepthThreshold` - Target value for depth to activate the scaler. (Default `0`, Optional)
+
+> **Notice:**
+> - Since ["channels are created on first use by subscribing to the named channel"](https://nsq.io/overview/design.html#simplifying-configuration-and-administration), the topic depth is used instead of the channel depth when the channel does not yet exist on an [nsqd](https://nsq.io/components/nsqd.html) instance. This allows KEDA to effectively bootstrap new channels when the `idleReplicaCount` is 0.
+> - If the message flow for a channel is paused, KEDA will not scale up consumers of the channel, regardless of the depth.
+
+### Example
+
+```yaml
+apiVersion: keda.sh/v1alpha1
+kind: ScaledObject
+metadata:
+  name: nsq-scaledobject
+spec:
+  scaleTargetRef:
+    name: nsq-consumer-deployment
+  triggers:
+  - type: nsq
+    metadata:
+      nsqLookupdHTTPAddresses: "nsq-nsqlookupd.nsq:4161"
+      topic: "example_topic"
+      channel: "example_channel"
+      depthThreshold: "10"
+      activationDepthThreshold: "0"
+```