Updates exception handling with FlowFrameworkException AND adds dryrun param to Create Workflow

[joshpalis]

Description

This PR updates the workflow parsing, workflow validation, workflow execution and rest action exception handling to throw FlowFrameworkExceptions with the correct REST Status code.

Note : I have opted not to throw FlowFrameworkExceptions for any of the workflow steps, since these steps are executed after we return a rest response back to the user. FlowFrameworkExceptions allow us to control the status of a rest response, since workflow step exceptions will be indexed into the user_outputs field of the State index, there's no need for a rest status for those cases

Example Create workflow request with missing create_connector_step :

curl -i -XPOST "localhost:9200/_plugins/_flow_framework/workflow" -H "Content-Type:application/json" --data '{"name":"deploy-register-model","description":"test case","use_case":"TEST_USE_CASE","version":{"template":"1.0.0","compatibility":["2.12.0","3.0.0"]},"workflows":{"provision":{"nodes":[{"id":"workflow_step_1","type":"register_model","user_inputs":{"name":"openAI-gpt-3.5-turbo","function_name":"remote","description":"test model"}},{"id":"workflow_step_2","type":"deploy_model","user_inputs":{}}],"edges":[{"source":"workflow_step_1","dest":"workflow_step_2"}]}}}'
HTTP/1.1 201 Created
X-OpenSearch-Version: OpenSearch/3.0.0-SNAPSHOT (opensearch)
content-type: application/json; charset=UTF-8
content-length: 38

{"workflow_id":"FuvPh4sBZkuHXaxzsBW4"}%  

Attempt to provision will fail due to graph validation, response is returned in the correct format with the correct rest status :

curl -i -XPOST "localhost:9200/_plugins/_flow_framework/workflow/FuvPh4sBZkuHXaxzsBW4/_provision?pretty"
HTTP/1.1 400 Bad Request
X-OpenSearch-Version: OpenSearch/3.0.0-SNAPSHOT (opensearch)
content-type: application/json; charset=UTF-8
content-length: 121

{
  "error" : "Request failed with exception: [Invalid graph, missing the following required inputs : [connector_id]]"
}

OpenSearch logs that graph validation failed :

[2023-10-31T22:16:57,149][INFO ][o.o.p.PluginsService     ] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] PluginService:onIndexModule index:[.plugins-ai-global-context/aKVyVY6yTlad7ns_OxmMPg]
[2023-10-31T22:16:57,171][INFO ][o.o.c.m.MetadataCreateIndexService] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] [.plugins-ai-global-context] creating index, cause [api], templates [], shards [1]/[1]
[2023-10-31T22:16:57,172][INFO ][o.o.c.r.a.AllocationService] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] updating number_of_replicas to [0] for indices [.plugins-ai-global-context]
[2023-10-31T22:16:57,198][INFO ][o.o.p.PluginsService     ] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] PluginService:onIndexModule index:[.plugins-ai-global-context/aKVyVY6yTlad7ns_OxmMPg]
[2023-10-31T22:16:57,249][INFO ][o.o.c.r.a.AllocationService] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] Cluster health status changed from [YELLOW] to [GREEN] (reason: [shards started [[.plugins-ai-global-context][0]]]).
[2023-10-31T22:16:57,270][INFO ][o.o.f.i.FlowFrameworkIndicesHandler] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] create index:.plugins-ai-global-context
[2023-10-31T22:16:57,305][INFO ][o.o.p.PluginsService     ] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] PluginService:onIndexModule index:[.plugins-workflow-state/QTgdVC7WS3qHY6vYwQE8Vw]
[2023-10-31T22:16:57,314][INFO ][o.o.c.m.MetadataCreateIndexService] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] [.plugins-workflow-state] creating index, cause [api], templates [], shards [1]/[1]
[2023-10-31T22:16:57,314][INFO ][o.o.c.r.a.AllocationService] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] updating number_of_replicas to [0] for indices [.plugins-workflow-state]
[2023-10-31T22:16:57,335][INFO ][o.o.p.PluginsService     ] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] PluginService:onIndexModule index:[.plugins-workflow-state/QTgdVC7WS3qHY6vYwQE8Vw]
[2023-10-31T22:16:57,379][INFO ][o.o.c.r.a.AllocationService] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] Cluster health status changed from [YELLOW] to [GREEN] (reason: [shards started [[.plugins-workflow-state][0]]]).
[2023-10-31T22:16:57,397][INFO ][o.o.f.i.FlowFrameworkIndicesHandler] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] create index:.plugins-workflow-state
[2023-10-31T22:16:57,409][INFO ][o.o.f.t.CreateWorkflowTransportAction] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] create state workflow doc
[2023-10-31T22:17:20,174][ERROR][o.o.f.t.ProvisionWorkflowTransportAction] [dev-dsk-jpalis-2c-27c8aa11.us-west-2.amazon.com] Workflow validation failed for workflow : FuvPh4sBZkuHXaxzsBW4

Issues Resolved

Part of #88
#99

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[codecov]

Codecov Report

Merging #137 (6b364c6) into main (ac76a44) will decrease coverage by 1.97%.
The diff coverage is 31.20%.

@@             Coverage Diff              @@
##               main     #137      +/-   ##
============================================
- Coverage     69.05%   67.09%   -1.97%     
- Complexity      302      311       +9     
============================================
  Files            37       37              
  Lines          1393     1468      +75     
  Branches        132      139       +7     
============================================
+ Hits            962      985      +23     
- Misses          386      434      +48     
- Partials         45       49       +4     

Files	Coverage Δ
...g/opensearch/flowframework/common/CommonValue.java	100.00% <ø> (ø)
...lowframework/exception/FlowFrameworkException.java	45.45% <100.00%> (+5.45%)	⬆️
...earch/flowframework/transport/WorkflowRequest.java	100.00% <100.00%> (ø)
...a/org/opensearch/flowframework/model/Template.java	89.36% <0.00%> (ø)
.../flowframework/workflow/WorkflowProcessSorter.java	97.82% <87.50%> (+0.02%)	⬆️
...rk/transport/ProvisionWorkflowTransportAction.java	49.27% <33.33%> (ø)
...lowframework/rest/RestProvisionWorkflowAction.java	48.00% <35.00%> (-24.73%)	⬇️
...h/flowframework/rest/RestCreateWorkflowAction.java	44.00% <30.00%> (-22.67%)	⬇️
...ework/transport/CreateWorkflowTransportAction.java	45.71% <29.62%> (-9.61%)	⬇️
...framework/indices/FlowFrameworkIndicesHandler.java	29.18% <2.85%> (-2.39%)	⬇️

[owaiskazi19]

Looks good overall. General comment. Concatenate the error message with e.getMessage() in FlowFrameworkException.

[joshpalis]

I've actioned #99 as well in this PR.
This adds a dryrun param to the create workflow API, which if true, attempts to validate each workflow before saving the template.

Example create workflow request with a cyclical graph

curl -i -XPOST "localhost:9200/_plugins/_flow_framework/workflow?dryrun=true" -H "Content-Type:application/json" --data '{"name":"create-connector-register-deploy-model","description":"test case","use_case":"TEST_CASE","version":{"template":"1.0.0","compatibility":["2.12.0","3.0.0"]},"workflows":{"provision":{"nodes":[{"id":"workflow_step_1","type":"create_connector","user_inputs":{"name":"OpenAI Chat Connector","description":"The connector to public OpenAI model service for GPT 3.5","version":"1","protocol":"http","parameters":{"endpoint":"api.openai.com","model":"gpt-3.5-turbo"},"credential":{"openAI_key":"..."},"actions":[{"action_type":"predict","method":"POST","url":"https://${parameters.endpoint}/v1/chat/completions"}]}},{"id":"workflow_step_2","type":"register_model","previous_node_inputs":{"workflow_step_1":"connector_id"},"user_inputs":{"name":"openAI-gpt-3.5-turbo","function_name":"remote","description":"test model"}},{"id":"workflow_step_3","type":"deploy_model","previous_node_inputs":{"workflow_step_2":"model_id"}}],"edges":[{"source":"workflow_step_1","dest":"workflow_step_2"},{"source":"workflow_step_2","dest":"workflow_step_3"},{"source":"workflow_step_3","dest":"workflow_step_1"}]}}}'
HTTP/1.1 400 Bad Request
X-OpenSearch-Version: OpenSearch/3.0.0-SNAPSHOT (opensearch)
content-type: application/json; charset=UTF-8
content-length: 98

{"error":"Request failed with exception: [No start node detected: all nodes have a predecessor.]"}

[owaiskazi19]

LGTM! One suggestion is to keep the PR shorter and making it easy for review.

[dbwiddis]

Great work!

We're pretty inconsistent with our error messages. Not sure if we're too far gone to do anything about it though!