Enable execution of lazy expressions server-side

Author: Luke Shaw

caterva2/client.py

@@ -1130,7 +1130,7 @@ def copy(self, src, dst):
         )
         return pathlib.PurePosixPath(result)
 
-    def lazyexpr(self, name, expression, operands=None):
+    def lazyexpr(self, name, expression, operands=None, compute=False):
         """
         Creates a lazy expression dataset in personal space.
 
@@ -1145,6 +1145,10 @@ def lazyexpr(self, name, expression, operands=None):
             Expression to be evaluated, which must yield a lazy expression.
         operands : dict
             Mapping of variables in the expression to their corresponding dataset paths.
+        compute : bool, optional
+            If false, generate lazyexpr and do not compute anything.
+            If true, compute lazy expression on creation and save (full) result.
+            Default false.
 
         Returns
         -------
@@ -1173,7 +1177,7 @@ def lazyexpr(self, name, expression, operands=None):
                 "User has not provided operands for the LazyExpression. Proceeding with empty operands arg"
             )
             operands = {}
-        expr = {"name": name, "expression": expression, "operands": operands}
+        expr = {"name": name, "expression": expression, "operands": operands, "lazy": not compute}
         dataset = api_utils.post(f"{self.urlbase}/api/lazyexpr/", expr, auth_cookie=self.cookie)
         return pathlib.PurePosixPath(dataset)
 

caterva2/models.py

@@ -65,6 +65,7 @@ class NewLazyExpr(pydantic.BaseModel):
     name: str
     expression: str
     operands: dict[str, str]
+    lazy: bool
 
 
 class MoveCopyPayload(pydantic.BaseModel):

caterva2/services/sub.py

@@ -969,7 +969,7 @@ def error(msg):
         return fastapi.HTTPException(status_code=400, detail=msg)  # bad request
 
     try:
-        result_path = make_expr(expr.name, expr.expression, expr.operands, user)
+        result_path = make_expr(expr.name, expr.expression, expr.operands, user, expr.lazy)
     except (SyntaxError, ValueError, TypeError) as exc:
         raise error(f"Invalid name or expression: {exc}") from exc
     except KeyError as ke: