example for pod spec from output of previous step (argoproj#1724)

examples/pod-spec-from-previous-step.yaml

@@ -0,0 +1,42 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Workflow
+metadata:
+  generateName: pod-spec-from-previous-step-
+spec:
+  entrypoint: workflow
+  templates:
+  - name: workflow
+    dag:
+      tasks:
+      - name: parse-resources
+        template: parse-resources-tmpl
+      - name: setup-resources
+        dependencies: [parse-resources]
+        template: setup-resources-tmpl
+        arguments:
+          parameters:
+            - name: resources
+              value: "{{tasks.parse-resources.outputs.parameters.resources}}"
+
+  - name: parse-resources-tmpl
+    outputs:
+      parameters:
+        - name: resources
+          valueFrom:
+            path: /tmp/resources.json
+    script:
+      image: alpine:latest
+      command: [sh]
+      source: |
+        echo '{"memory": "10Gi", "cpu": "2000m"}' > /tmp/resources.json && cat /tmp/resources.json
+
+  - name: setup-resources-tmpl
+    inputs:
+      parameters:
+      - name: resources
+    podSpecPatch: '{"containers":[{"name":"main", "resources":{"limits": {{inputs.parameters.resources}}, "requests": {{inputs.parameters.resources}} }}]}'
+    script:
+      image: alpine:latest
+      command: [sh]
+      source: |
+        echo {{inputs.parameters.resources}}