Add configurable request_delay support to server and models

openapi/index_openapi.json

@@ -1710,6 +1710,12 @@
  "type": "string",
  "description": "response string from the server"
  },
+ "request_delay": {
+ "title": "Request Delay",
+ "minimum": 0.0,
+ "type": "number",
+ "description": "A non-negative float giving time in seconds that the client is suggested to wait before issuing a subsequent request."
+ },
  "implementation": {
  "title": "Implementation",
  "allOf": [

openapi/openapi.json

@@ -3280,6 +3280,12 @@
  "type": "string",
  "description": "response string from the server"
  },
+ "request_delay": {
+ "title": "Request Delay",
+ "minimum": 0.0,
+ "type": "number",
+ "description": "A non-negative float giving time in seconds that the client is suggested to wait before issuing a subsequent request."
+ },
  "implementation": {
  "title": "Implementation",
  "allOf": [

optimade/models/optimade_json.py

@@ -4,7 +4,14 @@
 from enum import Enum
 from typing import Any, Dict, List, Optional, Type, Union
 
-from pydantic import AnyHttpUrl, AnyUrl, BaseModel, EmailStr, root_validator
+from pydantic import (
+ AnyHttpUrl,
+ AnyUrl,
+ BaseModel,
+ EmailStr,
+ NonNegativeFloat,
+ root_validator,
+)
 
 from optimade.models import jsonapi
 from optimade.models.utils import SemanticVersion, StrictField
@@ -313,6 +320,11 @@ class ResponseMeta(jsonapi.Meta):
  None, description="response string from the server"
  )
 
+ request_delay: Optional[NonNegativeFloat] = StrictField(
+ None,
+ description="A non-negative float giving time in seconds that the client is suggested to wait before issuing a subsequent request.",
+ )
+
  implementation: Optional[Implementation] = StrictField(
  None, description="a dictionary describing the server implementation"
  )

optimade/server/config.py

@@ -292,13 +292,27 @@ class ServerConfig(BaseSettings):
  description="If True, the server will check whether the query parameters given in the request are correct.",
  )
 
+ request_delay: Optional[float] = Field(
+ None,
+ description=(
+ "The value to use for the `meta->request_delay` field, which indicates to clients how long they should leave between success queries."
+ ),
+ )
+
  @validator("implementation", pre=True)
  def set_implementation_version(cls, v):
  """Set defaults and modify bypassed value(s)"""
  res = {"version": __version__}
  res.update(v)
  return res
 
+ @validator("request_delay", pre=True)
+ def check_request_delay(cls, v):
+ """Check `request_delay` is non-negative."""
+ if v is not None and v < 0:
+ raise ValueError("`request_delay` must be non-negative")
+ return v
+
  @root_validator(pre=True)
  def use_real_mongo_override(cls, values):
  """Overrides the `database_backend` setting with MongoDB and

optimade/server/routers/utils.py

@@ -76,6 +76,10 @@ def meta_values(
  if schema is None:
  schema = CONFIG.schema_url if not CONFIG.is_index else CONFIG.index_schema_url
 
+ if CONFIG.request_delay is not None:
+ # Add request delay via **kwargs only so that it is not set to null by default
+ kwargs["request_delay"] = CONFIG.request_delay
+
  return ResponseMeta(
  query=ResponseMetaQuery(representation=f"{url_path}?{url.query}"),
  api_version=__api_version__,