Add exponential back-off to retryStrategy

api/openapi-spec/swagger.json

@@ -188,6 +188,21 @@
         }
       }
     },
+    "io.argoproj.workflow.v1alpha1.Backoff": {
+      "type": "object",
+      "properties": {
+        "duration": {
+          "type": "string"
+        },
+        "factor": {
+          "type": "integer",
+          "format": "int32"
+        },
+        "maxDuration": {
+          "type": "string"
+        }
+      }
+    },
     "io.argoproj.workflow.v1alpha1.ContinueOn": {
       "description": "ContinueOn defines if a workflow should continue even if a task or step fails/errors. It can be specified if the workflow should continue when the pod errors, fails or both.",
       "type": "object",
@@ -796,6 +811,10 @@
       "description": "RetryStrategy provides controls on how to retry a workflow step",
       "type": "object",
       "properties": {
+        "backoff": {
+          "description": "Backoff is a backoff strategy",
+          "$ref": "#/definitions/io.argoproj.workflow.v1alpha1.Backoff"
+        },
         "limit": {
           "description": "Limit is the maximum number of attempts when retrying a container",
           "type": "integer",

examples/retry-backoff.yaml

@@ -0,0 +1,20 @@
+# This example demonstrates the use of retry back offs
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+  generateName: retry-backoff-
+spec:
+  entrypoint: retry-backoff
+  templates:
+  - name: retry-backoff
+    retryStrategy:
+      limit: 10
+      backoff:
+        duration: 1       # Default unit is seconds. Could also be a Duration, e.g.: "2m", "6h", "1d"
+        factor: 2
+        maxDuration: "1m" # Default unit is seconds. Could also be a Duration, e.g.: "2m", "6h", "1d"
+    container:
+      image: python:alpine3.6
+      command: ["python", -c]
+      # fail with a 66% probability
+      args: ["import random; import sys; exit_code = random.choice([0, 1, 1]); sys.exit(exit_code)"]