Replacing jsonpath with jq and adding 'expressionLang' top level property (#249)

* replacing jsonpath with jq

Signed-off-by: Tihomir Surdilovic <[email protected]>

* updates per comments

Signed-off-by: Tihomir Surdilovic <[email protected]>

* adding expressionlange prop and description

Signed-off-by: Tihomir Surdilovic <[email protected]>

Author: Tihomir Surdilovic

comparisons/comparison-argo.md

@@ -90,7 +90,7 @@ states:
   - functionRef:
       refName: whalesayimage
       arguments:
-        message: "{{ $.message }}"
+        message: "${ .message }"
   end: true
 ```
 
@@ -397,23 +397,23 @@ functions:
   metadata:
     image: alpine:latest
     command: sh, -c
-    source: 'echo result was: {{inputs.parameters.message}}'
+    source: 'echo result was: ${ .inputs.parameters.message }'
 states:
 - name: generate
   type: operation
   start: true
   actions:
   - functionRef: gen-random-int-bash
     actionDataFilter:
-      dataResultsPath: "{{ $.results }}"
+      dataResultsPath: "${ .results }"
   transition: print-message
 - name: print-message
   type: operation
   actions:
   - functionRef:
       refName: printmessagefunc
       arguments:
-        message: "{{ $.results }}"
+        message: "${ .results }"
   end: true
 ```
 
@@ -486,14 +486,14 @@ states:
   transition: printgreetings
 - name: printgreetings
   type: foreach
-  inputCollection: "{{ $.greetings }}"
+  inputCollection: "${ .greetings }"
   iterationParam: greeting
   actions:
   - name: print-message
     functionRef:
       refName: whalesay
       arguments:
-        message: "{{ $.greeting }}"
+        message: "${ .greeting }"
   end: true
 ```
 
@@ -582,14 +582,14 @@ states:
   actions:
   - functionRef: flip-coin-function
     actionDataFilter:
-      dataResultsPath: "{{ $.flip.result }}"
+      dataResultsPath: "${ .flip.result }"
   transition: show-flip-results
 - name: show-flip-results
   type: switch
   dataConditions:
-  - condition: "{{ $.flip[?(@.result == 'heads')] }}"
+  - condition: "${ .flip | .result == \"heads\" }"
     transition: show-results-heads
-  - condition: "{{ $.flip[?(@.result == 'tails')] }}"
+  - condition: "${ .flip | .result == \"tails\" }"
     transition: show-results-tails
 - name: show-results-heads
   type: operation
@@ -762,14 +762,14 @@ states:
   actions:
   - functionRef: flip-coin-function
     actionDataFilter:
-      dataResultsPath: "{{ $.steps.flip-coin.outputs.result }}" 
+      dataResultsPath: "${ .steps.flip-coin.outputs.result }" 
   transition: flip-coin-check
 - name: flip-coin-check
   type: switch
   dataConditions:
-  - condition: "{{ $.steps.flip-coin.outputs[?(@.result == 'tails')] }}"
+  - condition: "${ .steps.flip-coin.outputs | .result == \"tails\" }"
     transition: flip-coin-state
-  - condition: "{{ $.steps.flip-coin.outputs[?(@.result == 'heads')] }}"
+  - condition: "${ .steps.flip-coin.outputs | .result == \"heads\" }"
     transition: heads-state
 - name: heads-state
   type: operation
@@ -791,7 +791,7 @@ states:
 [Argo Example](https://github.com/argoproj/argo/tree/master/examples#exit-handlers)
 
 *Note*: With Serverless Workflow specification we can handle Argos "onExit" functionality
-in couple of ways. One is the "onErrors" functionality to define errors and transition to the parts
+in a couple of ways. One is the "onErrors" functionality to define errors and transition to the parts
 of workflow which is capable of handling the errors. 
 Another is to send an event at the end of workflow execution 
 which includes the workflow status. This event can then trigger execution other workflows
@@ -885,14 +885,14 @@ states:
   - functionRef:
       refName: send-email-function
       arguments:
-        args: 'echo send e-mail: $.workflow.name $.exit-code'
+        args: "echo send e-mail: ${ .workflow.name } ${ .workflow.status }"
   transition: emo-state
 - name: emo-state
   type: switch
   dataConditions:
-  - condition: "{{ $[?(@.exit_code == '1')] }}"
+  - condition: "${ .workflow| .status == \"Succeeded\" }"
     transition: celebrate-state
-  - condition: "{{ $[?(@.exit_code != '1')] }}"
+  - condition: "${ .workflow| .status != \"Succeeded\" }"
     transition: cry-state
 - name: celebrate-state
   type: operation

comparisons/comparison-brigade.md

@@ -188,7 +188,7 @@ states:
     functionRef:
       refName: consoleLogFunction
       arguments:
-        log: Caught Exception ${ .exception }
+        log: "Caught Exception ${ .exception }"
   end: true
 ```
 
@@ -403,18 +403,18 @@ states:
   - eventRefs:
     - execEvent
     eventDataFilter:
-      dataOutputPath: "{{ $.event }}"
+      dataOutputPath: "${ .event }"
     actions:
     - name: eventInfoAction
       functionRef:
         refName: consoleFunction
         arguments:
-          log: ">>> event $event.type caused by $.event.data.provider"
+          log: ">>> event ${ .event.type } caused by ${ .event.data.provider }"
     - name: projectInfoAction
       functionRef:
         refName: consoleFunction
         arguments:
-          log: ">>> project $event.data.project.name clones the repo at by $.event.data.repo.cloneURL"
+          log: ">>> project ${ .event.data.project.name } clones the repo at by ${ .event.data.repo.cloneURL }"
   end: true
 
 ```
@@ -484,18 +484,18 @@ states:
   - eventRefs:
     - execEvent
     eventDataFilter:
-      dataOutputPath: "{{ $.event }}"
+      dataOutputPath: "${ .event }"
     actions:
     - name: helloAction
       actionDataFilter:
-        dataResultsPath: "{{ $.helloResult }}"
+        dataResultsPath: "${ .helloResult }"
       functionRef:
         refName: greetingFunction
         arguments:
           message: hello
     - name: worldAction
       actionDataFilter:
-        dataResultsPath: "{{ $.worldResults }}"
+        dataResultsPath: "${ .worldResults }"
       functionRef:
         refName: greetingAction
         arguments:
@@ -504,8 +504,8 @@ states:
       functionRef:
         refName: storeToFileFunction
         arguments:
-          destination: "{{ $.event.destination }}"
-          value: "{{ $.helloResult }} {{ $.worldResults }}"
+          destination: "${ .event.destination }"
+          value: "${ .helloResult } ${ .worldResults }"
   end: true
 
 ```
@@ -572,31 +572,31 @@ states:
     - execEvent
     actions: []
     eventDataFilter:
-      dataOutputPath: "{{ $.execEvent }}"
+      dataOutputPath: "${ .execEvent }"
   transition:
     nextState: NextEventState
     produceEvents:
     - eventRef: nextEvent
       data:
         type: next
         provider: exec-handler
-        buildID: "{{ $.execEvent.data.buildID }}"
-        workerID: "{{ $.execEvent.data.workerID }}"
+        buildID: "${ .execEvent.data.buildID }"
+        workerID: "${ .execEvent.data.workerID }"
         cause:
-          event: "{{ $.execEvent }}"
+          event: "${ .execEvent }"
 - name: NextEventState
   type: event
   onEvents:
   - eventRefs:
     - nextEvent
     eventDataFilter:
-      dataOutputPath: "{{ $.nextEvent }}"
+      dataOutputPath: "${ .nextEvent }"
     actions:
     - name: consoleLogAction
       functionRef:
         refName: consoleLogFunction
         arguments:
-          log: fired $.nextEvent.data.type caused by $.nextEvent.data.cause.event
+          log: "fired ${ .nextEvent.data.type } caused by ${ .nextEvent.data.cause.event }"
   end: true
 ```
 

comparisons/comparison-cadence.md

@@ -199,13 +199,13 @@ states:
   - functionRef:
       refName: processfilefunction
       arguments:
-        filename: "{{ $file.name }}"
+        filename: "${ .file.name }"
     actionDataFilter:
-      dataResultsPath: "{{ $.processed }}"
+      dataResultsPath: "${ .processed }"
   - functionRef:
       refName: uploadfunction
       arguments:
-        file: "{{ $processed }}"
+        file: "${ .processed }"
   onErrors:
   - error: "*"
     retryRef: fileprocessingretry

comparisons/comparison-google-cloud-workflows.md

@@ -92,10 +92,10 @@ languages.
             "type": "inject",
             "start": true,
             "data": {
-                "outputVar": "Hello {{ $.firstName }} {{ $.lastName }}"
+                "outputVar": "Hello ${ .firstname + \" \" +  .lastname  }"
             },
             "stateDataFilter": {
-                "dataOutputPath": "{{ $.outputVar }}"
+                "dataOutputPath": "${ .outputVar }"
              },
             "end": true
         }
@@ -206,7 +206,7 @@ instance is created. See the Serverless Workflow ["Workflow Data"](../specificat
                 ]
             },
             "stateDataFilter": {
-                "dataOutputPath": "{{ concat($.array.[*]) }}"
+                "dataOutputPath": "${ .array | join(\"\") }"
              },
             "end": true
         }
@@ -228,10 +228,9 @@ The second step, "exit-loop" is then used alongside the "return" keyword to spec
 workflow results.
 With Serverless Workflow we can inject the array data via the "inject" state again, or 
 it can simply be passed as workflow data input. There is no need for looping here as
-we can just utilize the JsonPath "concat" method as shown in the states data filter.
+we can just utilize the [jq "join" function](https://stedolan.github.io/jq/manual/#join(str)) as shown in the states data filter.
 We could use the [ForEach state](../specification.md#ForEach-State) for iteration of 
-array values, however 
-it just complicates things and is not needed.
+array values, however it would just unnecessarily complicate things.
 
 ### Connect Compute Engine
 
@@ -294,9 +293,9 @@ it just complicates things and is not needed.
                     "functionRef": {
                         "refName": "StopComputeEngine",
                         "arguments": {
-                            "project": "{{ $.project }}",
-                            "zone": "{{ $.zone }}",
-                            "vmToStop": "{{ $.vmToStop }}"
+                            "project": "${ .project }",
+                            "zone": "${ .zone }",
+                            "vmToStop": "${ .vmToStop }"
                         }
                     }
                 }
@@ -424,9 +423,9 @@ as service invocations, where as Google Workflow uses the "call" keyword.
                     "functionRef": {
                         "refName": "PublishToTopic",
                         "arguments": {
-                            "project": "{{ $.project }}",
-                            "topic": "{{ $.topic }}",
-                            "message": "{{ $.message }}"
+                            "project": "${ .project }",
+                            "topic": "${ .topic }",
+                            "message": "${ .message }"
                         }
                     }
                 }
@@ -795,12 +794,12 @@ a separate workflow definition with the "id" parameter set to "calledsubflow" in
             "dataConditions": [
                 {
                     "name": "Less than 10",
-                    "condition": "{{ $.body[?(@.SomeField < 10)] }}",
+                    "condition": "${ .body |  .SomeField < 10 }",
                     "transition": "CallSmall"
                 },
                 {
                     "name": "Less than 100",
-                    "condition": "{{ $.body[?(@.SomeField < 100)] }}",
+                    "condition": "${ .body |  .SomeField < 100 }",
                     "transition": "CallMedium"
                 }
             ],