Add enpoint for debug sessions

Author: dmashuda

internal/dev_server/api/api.yaml

@@ -188,6 +188,34 @@ paths:
           $ref: "#/components/responses/ErrorResponse"
         400:
           $ref: "#/components/responses/ErrorResponse"
+  /dev/debug-sessions:
+    get:
+      operationId: getDebugSessions
+      summary: list all debug sessions with event counts
+      parameters:
+        - name: limit
+          in: query
+          description: limit the number of debug sessions returned
+          required: false
+          schema:
+            type: integer
+            default: 50
+        - name: offset
+          in: query
+          description: offset for pagination
+          required: false
+          schema:
+            type: integer
+            default: 0
+      responses:
+        200:
+          description: OK. List of debug sessions
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/DebugSessionsPage"
+        400:
+          $ref: "#/components/responses/ErrorResponse"
 components:
   parameters:
     flagKey:
@@ -294,6 +322,45 @@ components:
           type: string
         name:
           type: string
+    DebugSession:
+      description: Debug session with event count
+      type: object
+      required:
+        - key
+        - written_at
+        - event_count
+      properties:
+        key:
+          type: string
+          description: unique identifier for the debug session
+        written_at:
+          type: string
+          format: date-time
+          description: timestamp when the debug session was created
+        event_count:
+          type: integer
+          format: int64
+          description: number of events associated with this debug session
+    DebugSessionsPage:
+      description: Paginated response of debug sessions
+      type: object
+      required:
+        - sessions
+        - total_count
+        - has_more
+      properties:
+        sessions:
+          type: array
+          items:
+            $ref: "#/components/schemas/DebugSession"
+          description: list of debug sessions
+        total_count:
+          type: integer
+          format: int64
+          description: total number of debug sessions available
+        has_more:
+          type: boolean
+          description: whether there are more results available
   responses:
     FlagOverride:
       description: Flag override

internal/dev_server/api/get_debug_sessions.go

@@ -0,0 +1,61 @@
+package api
+
+import (
+	"context"
+
+	"github.com/launchdarkly/ldcli/internal/dev_server/model"
+)
+
+func (s server) GetDebugSessions(ctx context.Context, request GetDebugSessionsRequestObject) (GetDebugSessionsResponseObject, error) {
+	eventStore := model.EventStoreFromContext(ctx)
+
+	// Set default values for pagination
+	limit := 50
+	offset := 0
+
+	if request.Params.Limit != nil {
+		limit = *request.Params.Limit
+	}
+	if request.Params.Offset != nil {
+		offset = *request.Params.Offset
+	}
+
+	// Validate parameters
+	if limit < 1 || limit > 1000 {
+		return GetDebugSessions400JSONResponse{ErrorResponseJSONResponse{
+			Code:    "invalid_parameter",
+			Message: "limit must be between 1 and 1000",
+		}}, nil
+	}
+
+	if offset < 0 {
+		return GetDebugSessions400JSONResponse{ErrorResponseJSONResponse{
+			Code:    "invalid_parameter",
+			Message: "offset must be non-negative",
+		}}, nil
+	}
+
+	// Query debug sessions from the event store
+	page, err := eventStore.QueryDebugSessions(ctx, limit, offset)
+	if err != nil {
+		return nil, err
+	}
+
+	// Convert model.DebugSession to API DebugSession
+	var apiSessions []DebugSession
+	for _, session := range page.Sessions {
+		apiSessions = append(apiSessions, DebugSession{
+			Key:        session.Key,
+			WrittenAt:  session.WrittenAt,
+			EventCount: session.EventCount,
+		})
+	}
+
+	response := DebugSessionsPage{
+		Sessions:   apiSessions,
+		TotalCount: page.TotalCount,
+		HasMore:    page.HasMore,
+	}
+
+	return GetDebugSessions200JSONResponse(response), nil
+}