Substitute REST path or body parameters in Workflow Steps

CHANGELOG.md

@@ -15,6 +15,8 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 ## [Unreleased 2.x](https://github.com/opensearch-project/flow-framework/compare/2.12...2.x)
 ### Features
 ### Enhancements
+- Substitute REST path or body parameters in Workflow Steps ([#525](https://github.com/opensearch-project/flow-framework/pull/525))
+
 ### Bug Fixes
 ### Infrastructure
 ### Documentation

src/main/java/org/opensearch/flowframework/rest/RestCreateWorkflowAction.java

@@ -29,6 +29,9 @@
 import java.io.IOException;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
 import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.flowframework.common.CommonValue.PROVISION_WORKFLOW;
@@ -75,6 +78,19 @@ protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient cli
         String workflowId = request.param(WORKFLOW_ID);
         String[] validation = request.paramAsStringArray(VALIDATION, new String[] { "all" });
         boolean provision = request.paramAsBoolean(PROVISION_WORKFLOW, false);
+        final List<String> validCreateParams = List.of(WORKFLOW_ID, VALIDATION, PROVISION_WORKFLOW);
+        // If provisioning, consume all other params and pass to provision transport action
+        Map<String, String> params = provision
+            ? request.params()
+                .keySet()
+                .stream()
+                .filter(k -> !validCreateParams.contains(k))
+                .collect(Collectors.toMap(Function.identity(), request::param))
+            : request.params()
+                .entrySet()
+                .stream()
+                .filter(e -> !validCreateParams.contains(e.getKey()))
+                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
         if (!flowFrameworkSettings.isFlowFrameworkEnabled()) {
             FlowFrameworkException ffe = new FlowFrameworkException(
                 "This API is disabled. To enable it, set [" + FLOW_FRAMEWORK_ENABLED.getKey() + "] to true.",
@@ -84,12 +100,24 @@ protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient cli
                 new BytesRestResponse(ffe.getRestStatus(), ffe.toXContent(channel.newErrorBuilder(), ToXContent.EMPTY_PARAMS))
             );
         }
+        if (!provision && !params.isEmpty()) {
+            // Consume params and content so custom exception is processed
+            params.keySet().stream().forEach(request::param);
+            request.content();
+            FlowFrameworkException ffe = new FlowFrameworkException(
+                "Only the parameters " + validCreateParams + " are permitted unless the provision parameter is set to true.",
+                RestStatus.BAD_REQUEST
+            );
+            return channel -> channel.sendResponse(
+                new BytesRestResponse(ffe.getRestStatus(), ffe.toXContent(channel.newErrorBuilder(), ToXContent.EMPTY_PARAMS))
+            );
+        }
         try {
             XContentParser parser = request.contentParser();
             ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
             Template template = Template.parse(parser);
 
-            WorkflowRequest workflowRequest = new WorkflowRequest(workflowId, template, validation, provision);
+            WorkflowRequest workflowRequest = new WorkflowRequest(workflowId, template, validation, provision, params);
 
             return channel -> client.execute(CreateWorkflowAction.INSTANCE, workflowRequest, ActionListener.wrap(response -> {
                 XContentBuilder builder = response.toXContent(channel.newBuilder(), ToXContent.EMPTY_PARAMS);

src/main/java/org/opensearch/flowframework/rest/RestProvisionWorkflowAction.java

@@ -16,6 +16,7 @@
 import org.opensearch.core.rest.RestStatus;
 import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.core.xcontent.XContentParser;
 import org.opensearch.flowframework.common.FlowFrameworkSettings;
 import org.opensearch.flowframework.exception.FlowFrameworkException;
 import org.opensearch.flowframework.transport.ProvisionWorkflowAction;
@@ -27,7 +28,11 @@
 import java.io.IOException;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
+import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
 import static org.opensearch.flowframework.common.CommonValue.WORKFLOW_ID;
 import static org.opensearch.flowframework.common.CommonValue.WORKFLOW_URI;
 import static org.opensearch.flowframework.common.FlowFrameworkSettings.FLOW_FRAMEWORK_ENABLED;
@@ -69,23 +74,19 @@ public List<Route> routes() {
     protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient client) throws IOException {
         String workflowId = request.param(WORKFLOW_ID);
         try {
+            Map<String, String> params = parseParamsAndContent(request);
             if (!flowFrameworkFeatureEnabledSetting.isFlowFrameworkEnabled()) {
                 throw new FlowFrameworkException(
                     "This API is disabled. To enable it, update the setting [" + FLOW_FRAMEWORK_ENABLED.getKey() + "] to true.",
                     RestStatus.FORBIDDEN
                 );
             }
-            // Validate content
-            if (request.hasContent()) {
-                // BaseRestHandler will give appropriate error message
-                return channel -> channel.sendResponse(null);
-            }
             // Validate params
             if (workflowId == null) {
                 throw new FlowFrameworkException("workflow_id cannot be null", RestStatus.BAD_REQUEST);
             }
             // Create request and provision
-            WorkflowRequest workflowRequest = new WorkflowRequest(workflowId, null);
+            WorkflowRequest workflowRequest = new WorkflowRequest(workflowId, null, params);
             return channel -> client.execute(ProvisionWorkflowAction.INSTANCE, workflowRequest, ActionListener.wrap(response -> {
                 XContentBuilder builder = response.toXContent(channel.newBuilder(), ToXContent.EMPTY_PARAMS);
                 channel.sendResponse(new BytesRestResponse(RestStatus.OK, builder));
@@ -108,4 +109,31 @@ protected RestChannelConsumer prepareRequest(RestRequest request, NodeClient cli
         }
     }
 
+    private Map<String, String> parseParamsAndContent(RestRequest request) {
+        // Get any other params from path
+        Map<String, String> params = request.params()
+            .keySet()
+            .stream()
+            .filter(k -> !WORKFLOW_ID.equals(k))
+            .collect(Collectors.toMap(Function.identity(), request::param));
+        // If body is included get any params from body
+        if (request.hasContent()) {
+            try (XContentParser parser = request.contentParser()) {
+                ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
+                while (parser.nextToken() != XContentParser.Token.END_OBJECT) {
+                    String key = parser.currentName();
+                    if (params.containsKey(key)) {
+                        throw new FlowFrameworkException("Duplicate key " + key, RestStatus.BAD_REQUEST);
+                    }
+                    if (parser.nextToken() != XContentParser.Token.VALUE_STRING) {
+                        throw new FlowFrameworkException("Request body fields must have string values", RestStatus.BAD_REQUEST);
+                    }
+                    params.put(key, parser.text());
+                }
+            } catch (IOException e) {
+                throw new FlowFrameworkException("Request body parsing failed", RestStatus.BAD_REQUEST);
+            }
+        }
+        return params;
+    }
 }

src/main/java/org/opensearch/flowframework/transport/CreateWorkflowTransportAction.java

@@ -39,6 +39,7 @@
 import org.opensearch.transport.TransportService;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -282,7 +283,7 @@ void checkMaxWorkflows(TimeValue requestTimeOut, Integer maxWorkflow, ActionList
 
     private void validateWorkflows(Template template) throws Exception {
         for (Workflow workflow : template.workflows().values()) {
-            List<ProcessNode> sortedNodes = workflowProcessSorter.sortProcessNodes(workflow, null);
+            List<ProcessNode> sortedNodes = workflowProcessSorter.sortProcessNodes(workflow, null, Collections.emptyMap());
             workflowProcessSorter.validate(sortedNodes, pluginsService);
         }
     }

src/main/java/org/opensearch/flowframework/transport/DeprovisionWorkflowTransportAction.java

@@ -140,6 +140,7 @@
                     deprovisionStepId,
                     workflowStepFactory.createStep(deprovisionStep),
                     Collections.emptyMap(),
+                    Collections.emptyMap(),
                     new WorkflowData(Map.of(getResourceByWorkflowStep(stepName), resource.resourceId()), workflowId, deprovisionStepId),
                     Collections.emptyList(),
                     this.threadPool,
@@ -194,6 +195,7 @@
                         pn.id(),
                         workflowStepFactory.createStep(pn.workflowStep().getName()),
                         pn.previousNodeInputs(),
+                        pn.params(),
                         pn.input(),
                         pn.predecessors(),
                         this.threadPool,

src/main/java/org/opensearch/flowframework/transport/ProvisionWorkflowTransportAction.java

@@ -126,7 +126,11 @@ protected void doExecute(Task task, WorkflowRequest request, ActionListener<Work
 
                 // Sort and validate graph
                 Workflow provisionWorkflow = template.workflows().get(PROVISION_WORKFLOW);
-                List<ProcessNode> provisionProcessSequence = workflowProcessSorter.sortProcessNodes(provisionWorkflow, workflowId);
+                List<ProcessNode> provisionProcessSequence = workflowProcessSorter.sortProcessNodes(
+                    provisionWorkflow,
+                    workflowId,
+                    request.getParams()
+                );
                 workflowProcessSorter.validate(provisionProcessSequence, pluginsService);
 
                 flowFrameworkIndicesHandler.isWorkflowNotStarted(workflowId, workflowIsNotStarted -> {

src/main/java/org/opensearch/flowframework/transport/WorkflowRequest.java

@@ -16,6 +16,8 @@
 import org.opensearch.flowframework.model.Template;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.Map;
 
 /**
  * Transport Request to create, provision, and deprovision a workflow
@@ -43,12 +45,27 @@ public class WorkflowRequest extends ActionRequest {
     private boolean provision;
 
     /**
-     * Instantiates a new WorkflowRequest, set validation to false and set requestTimeout and maxWorkflows to null
+     * Params map
+     */
+    private Map<String, String> params;
+
+    /**
+     * Instantiates a new WorkflowRequest, set validation to all, no provisioning
      * @param workflowId the documentId of the workflow
      * @param template the use case template which describes the workflow
      */
     public WorkflowRequest(@Nullable String workflowId, @Nullable Template template) {
-        this(workflowId, template, new String[] { "all" }, false);
+        this(workflowId, template, new String[] { "all" }, false, Collections.emptyMap());
+    }
+
+    /**
+     * Instantiates a new WorkflowRequest with params map, set validation to all, provisioning to true
+     * @param workflowId the documentId of the workflow
+     * @param template the use case template which describes the workflow
+     * @param params The parameters from the REST path
+     */
+    public WorkflowRequest(String workflowId, @Nullable Template template, Map<String, String> params) {
+        this(workflowId, template, new String[] { "all" }, true, params);
     }
 
     /**
@@ -57,12 +74,23 @@ public WorkflowRequest(@Nullable String workflowId, @Nullable Template template)
      * @param template the use case template which describes the workflow
      * @param validation flag to indicate if validation is necessary
      * @param provision flag to indicate if provision is necessary
+     * @param params map of REST path params. If provision is false, must be an empty map.
      */
-    public WorkflowRequest(@Nullable String workflowId, @Nullable Template template, String[] validation, boolean provision) {
+    public WorkflowRequest(
+        @Nullable String workflowId,
+        @Nullable Template template,
+        String[] validation,
+        boolean provision,
+        Map<String, String> params
+    ) {
         this.workflowId = workflowId;
         this.template = template;
         this.validation = validation;
         this.provision = provision;
+        if (!provision && !params.isEmpty()) {
+            throw new IllegalArgumentException("Params may only be included when provisioning.");
+        }
+        this.params = params;
     }
 
     /**
@@ -77,6 +105,7 @@ public WorkflowRequest(StreamInput in) throws IOException {
         this.template = templateJson == null ? null : Template.parse(templateJson);
         this.validation = in.readStringArray();
         this.provision = in.readBoolean();
+        this.params = this.provision ? in.readMap(StreamInput::readString, StreamInput::readString) : Collections.emptyMap();
     }
 
     /**
@@ -113,13 +142,24 @@ public boolean isProvision() {
         return this.provision;
     }
 
+    /**
+     * Gets the params map
+     * @return the params map
+     */
+    public Map<String, String> getParams() {
+        return Map.copyOf(this.params);
+    }
+
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeOptionalString(workflowId);
         out.writeOptionalString(template == null ? null : template.toJson());
         out.writeStringArray(validation);
         out.writeBoolean(provision);
+        if (provision) {
+            out.writeMap(params, StreamOutput::writeString, StreamOutput::writeString);
+        }
     }
 
     @Override

src/main/java/org/opensearch/flowframework/util/ParseUtils.java

@@ -248,6 +248,7 @@ public static Map<String, String> getStringToStringMap(Object map, String fieldN
      * @param currentNodeInputs Input params and content for this node, from workflow parsing
      * @param outputs WorkflowData content of previous steps
      * @param previousNodeInputs Input params for this node that come from previous steps
+     * @param params Params that came from REST path
      * @return A map containing the requiredInputKeys with their corresponding values,
      *         and optionalInputKeys with their corresponding values if present.
      *         Throws a {@link FlowFrameworkException} if a required key is not present.
@@ -257,7 +258,8 @@ public static Map<String, Object> getInputsFromPreviousSteps(
         Set<String> optionalInputKeys,
         WorkflowData currentNodeInputs,
         Map<String, WorkflowData> outputs,
-        Map<String, String> previousNodeInputs
+        Map<String, String> previousNodeInputs,
+        Map<String, String> params
     ) {
         // Mutable set to ensure all required keys are used
         Set<String> requiredKeys = new HashSet<>(requiredInputKeys);
@@ -308,11 +310,11 @@ public static Map<String, Object> getInputsFromPreviousSteps(
                     Map<String, Object> valueMap = (Map<String, Object>) value;
                     value = valueMap.entrySet()
                         .stream()
-                        .collect(Collectors.toMap(Map.Entry::getKey, e -> conditionallySubstitute(e.getValue(), outputs)));
+                        .collect(Collectors.toMap(Map.Entry::getKey, e -> conditionallySubstitute(e.getValue(), outputs, params)));
                 } else if (value instanceof List) {
-                    value = ((List<?>) value).stream().map(v -> conditionallySubstitute(v, outputs)).collect(Collectors.toList());
+                    value = ((List<?>) value).stream().map(v -> conditionallySubstitute(v, outputs, params)).collect(Collectors.toList());
                 } else {
-                    value = conditionallySubstitute(value, outputs);
+                    value = conditionallySubstitute(value, outputs, params);
                 }
                 // Add value to inputs and mark that a required key was present
                 inputs.put(key, value);
@@ -336,15 +338,21 @@ public static Map<String, Object> getInputsFromPreviousSteps(
         return inputs;
     }
 
-    private static Object conditionallySubstitute(Object value, Map<String, WorkflowData> outputs) {
+    private static Object conditionallySubstitute(Object value, Map<String, WorkflowData> outputs, Map<String, String> params) {
         if (value instanceof String) {
             Matcher m = SUBSTITUTION_PATTERN.matcher((String) value);
             if (m.matches()) {
+                // Try matching a previous step+value pair
                 WorkflowData data = outputs.get(m.group(1));
                 if (data != null && data.getContent().containsKey(m.group(2))) {
                     return data.getContent().get(m.group(2));
                 }
             }
+            // Replace all params if present
+            for (Entry<String, String> e : params.entrySet()) {
+                String regex = "\\$\\{\\{\\s*" + Pattern.quote(e.getKey()) + "\\s*\\}\\}";
+                value = ((String) value).replaceAll(regex, e.getValue());
+            }
         }
         return value;
     }

src/main/java/org/opensearch/flowframework/workflow/AbstractRegisterLocalModelStep.java

@@ -79,7 +79,8 @@ public PlainActionFuture<WorkflowData> execute(
         String currentNodeId,
         WorkflowData currentNodeInputs,
         Map<String, WorkflowData> outputs,
-        Map<String, String> previousNodeInputs
+        Map<String, String> previousNodeInputs,
+        Map<String, String> params
     ) {
 
         PlainActionFuture<WorkflowData> registerLocalModelFuture = PlainActionFuture.newFuture();
@@ -90,7 +91,8 @@ public PlainActionFuture<WorkflowData> execute(
                 getOptionalKeys(),
                 currentNodeInputs,
                 outputs,
-                previousNodeInputs
+                previousNodeInputs,
+                params
             );
 
             // Extract common fields of OS provided text-embedding, sparse encoding and custom models

src/main/java/org/opensearch/flowframework/workflow/CreateConnectorStep.java

@@ -74,7 +74,8 @@ public PlainActionFuture<WorkflowData> execute(
         String currentNodeId,
         WorkflowData currentNodeInputs,
         Map<String, WorkflowData> outputs,
-        Map<String, String> previousNodeInputs
+        Map<String, String> previousNodeInputs,
+        Map<String, String> params
     ) {
         PlainActionFuture<WorkflowData> createConnectorFuture = PlainActionFuture.newFuture();
 
@@ -138,7 +139,8 @@ public void onFailure(Exception e) {
                 optionalKeys,
                 currentNodeInputs,
                 outputs,
-                previousNodeInputs
+                previousNodeInputs,
+                params
             );
 
             String name = (String) inputs.get(NAME_FIELD);

src/main/java/org/opensearch/flowframework/workflow/CreateIndexStep.java

@@ -63,7 +63,8 @@ public PlainActionFuture<WorkflowData> execute(
         String currentNodeId,
         WorkflowData currentNodeInputs,
         Map<String, WorkflowData> outputs,
-        Map<String, String> previousNodeInputs
+        Map<String, String> previousNodeInputs,
+        Map<String, String> params
     ) {
         PlainActionFuture<WorkflowData> createIndexFuture = PlainActionFuture.newFuture();
         ActionListener<CreateIndexResponse> actionListener = new ActionListener<>() {