add mongoDB.md

content/docs/2.1/scalers/mongo.md

@@ -0,0 +1,110 @@
++++
+title = "mongoDB"
+layout = "scaler"
+maintainer = "Community"
+description = "Scale applications based on mongoDB."
+availability = "v2.1+"
+go_file = "mongoDB_scaler"
++++
+
+### Trigger Specification
+
+This specification describes the mongoDB trigger that scales based on result of mongoDB query.
+
+```yaml
+triggers:
+  - type: mongoDB
+    metadata:
+      # Required: database name
+      dbName: "test"
+      # Required: collection name
+      collection: "test_collection"
+      # Required: query expr, used by filter data
+      query: '{"region":"eu-1","state":"running","plan":"planA"}'
+      # Required: according to the number of query result, to scale job
+      queryValue: "1"
+```
+
+**Parameter list:**
+
+- `dbName`  - Name of the database
+- `collection` - Name of the collection
+- `query` - a mongoDB query that should return single numeric value
+- `queryValue` - a threshold that is used as targetAverageValue in HPA.
+
+To provide information about how to connect to mongoDB you can provide
+- `connectionStringFromEnv` - mongoDB connection string that should point to environment variable with valid value
+
+Or provide more detailed information:
+- `host` - The host of the mongoDB server
+- `port` - The port of the mongoDB server
+- `username` - Username to authenticate with to mongoDB database
+- `passwordFromEnv` - Password for the given user
+
+### Authentication Parameters 
+
+You can authenticate by using connection string or password authentication.
+
+**Connection String Authentication:**
+
+- `connectionString`  - Connection string for mongoDB database
+
+**Password Authentication:**
+
+- `password` - Password for the configured user to login to mongoDB database variables.
+
+### Example
+
+Here is an example of how to deploy a scaled Job with the `mongoDB` scale trigger which uses `TriggerAuthentication`.
+
+```yaml
+apiVersion: keda.sh/v1alpha1
+kind: ScaledJob
+metadata:
+  name: mongoDB-job
+spec:
+  jobTargetRef:
+    template:
+      spec:
+        containers:
+          - name: mongodb-update
+            image: 1314520999/mongodb-update:latest
+            args:
+            - --connectStr=mongodb://test_user:test_password@mongodb-svc.mongoDB.svc.cluster.local:27017/test
+            - --dataBase=test
+            - --collection=test_collection
+            imagePullPolicy: IfNotPresent
+        restartPolicy: Never
+    backoffLimit: 1
+  pollingInterval: 30             # Optional. Default: 30 seconds
+  maxReplicaCount: 30             # Optional. Default: 100
+  successfulJobsHistoryLimit: 0   # Optional. Default: 100. How many completed jobs should be kept.
+  failedJobsHistoryLimit: 10      # Optional. Default: 100. How many failed jobs should be kept.
+  triggers:
+    - type: mongoDB
+      metadata:
+        dbName: "test"
+        collection: "test_collection"
+        query: '{"region":"eu-1","state":"running","plan":"planA"}'
+        queryValue: "1"
+      authenticationRef:
+        name: mongoDB-trigger
+---
+apiVersion: keda.sh/v1alpha1
+kind: TriggerAuthentication
+metadata:
+  name: mongoDB-trigger
+spec:
+  secretTargetRef:
+    - parameter: connectionString
+      name: mongoDB-secret
+      key: connect
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: mongoDB-secret
+type: Opaque
+data:
+  connect: bW9uZ29kYjovL3Rlc3RfdXNlcjp0ZXN0X3Bhc3N3b3JkQG1vbmdvZGItc3ZjLm1vbmdvREIuc3ZjLmNsdXN0ZXIubG9jYWw6MjcwMTcvdGVzdA==
+```