http/2 429 error

gistfile1.txt

HTTP/2 429 
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date: Wed, 25 Mar 2026 03:22:37 GMT
server: scaffolding on HTTPServer2
content-length: 581
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server-timing: gfet4t7; dur=467
alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000

[{
  "error": {
    "code": 429,
    "message": "You exceeded your current quota, please check your plan and billing details. For more information on this error, head to: https://ai.google.dev/gemini-api/docs/rate-limits. To monitor your current usage, head to: https://ai.dev/rate-limit. \n* Quota exceeded for metric: generativelanguage.googleapis.com/generate_content_free_tier_requests, limit: 20, model: gemini-2.5-flash\nPlease retry in 22.906018063s.",
    "status": "RESOURCE_EXHAUSTED",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.Help",
        "links": [
          {
            "description": "Learn more about Gemini API quotas",
            "url": "https://ai.google.dev/gemini-api/docs/rate-limits"
          }
        ]
      },
      {
        "@type": "type.googleapis.com/google.rpc.QuotaFailure",
        "violations": [
          {
            "quotaMetric": "generativelanguage.googleapis.com/generate_content_free_tier_requests",
            "quotaId": "GenerateRequestsPerDayPerProjectPerModel-FreeTier",
            "quotaDimensions": {
              "location": "global",
              "model": "gemini-2.5-flash"
            },
            "quotaValue": "20"
          }
        ]
      },
      {
        "@type": "type.googleapis.com/google.rpc.RetryInfo",
        "retryDelay": "22s"
      }
    ]
  }
}
]

gistfile2.txt

(use-package gptel-gemini-key-rotation
  :ensure nil
  :after (gptel)
  :demand t
  :config
  ;; (gptel-backends-llama-swap)
  ;; (gptel-backends-vibe-proxy)
  (require 'gptel-gemini-key-rotation)
  (require 'gptel-gemini)
  (gptel-gemini-key-rotation-setup)
  (setq gptel-model 'gemini-2.5-flash
        gptel-backend
        (gptel-make-gemini-rotating "Gemini" :stream t
                                    :models '(gemini-2.5-flash gemini-2.5-pro gemini-2.5-flash-lite))))

gptel-gemini-key-rotation.el

;;; gptel-gemini-key-rotation.el --- Automatic Gemini API key rotation for gptel on errors -*- lexical-binding: t; -*-

;; This package provides automatic API key rotation for Gemini backends in gptel.
;; When a request fails (e.g., due to rate limiting or invalid key), it automatically
;; tries the next available key from authinfo.

(require 'gptel)
(require 'auth-source)

;;; Configuration

(defgroup gptel-gemini-key-rotation nil
  "Automatic API key rotation for Gemini backends in gptel."
  :group 'gptel)

(defcustom gptel-gemini-key-rotation-enabled t
  "Enable automatic key rotation for Gemini backends."
  :type 'boolean
  :group 'gptel-gemini-key-rotation)

(defcustom gptel-gemini-authinfo-host "generativelanguage.googleapis.com"
  "Host identifier for Gemini API keys in authinfo.
This is the 'machine' field in ~/.authinfo entries."
  :type 'string
  :group 'gptel-gemini-key-rotation)

(defcustom gptel-gemini-authinfo-user "apikey"
  "User identifier for Gemini API keys in authinfo.
This is the 'login' field in ~/.authinfo entries."
  :type 'string
  :group 'gptel-gemini-key-rotation)

(defcustom gptel-gemini-key-rotation-errors
  '("401" "403" "429" "key" "unauthorized" "forbidden" "rate limit" "quota")
  "List of error strings that trigger key rotation.
If any of these strings appear in the error message/status, rotation is attempted."
  :type '(repeat string)
  :group 'gptel-gemini-key-rotation)

;;; Internal Variables

(defvar gptel-gemini--key-ring nil
  "Cache of available Gemini API keys from authinfo.")
(defvar gptel-gemini--current-key-index 0
  "Index of the currently active key in the key ring.")
(defvar gptel-gemini--rotation-in-progress nil
  "Flag to prevent recursive rotation attempts.")

;;; Key Management

(defun gptel-gemini--fetch-all-keys ()
  "Fetch all Gemini API keys from authinfo.
Returns a list of (SECRET . METADATA) pairs."
  (let ((results (auth-source-search
                  :host gptel-gemini-authinfo-host
                  :user gptel-gemini-authinfo-user
                  :require '(:secret)
                  :max 100)))
    (mapcar (lambda (entry)
              (let ((secret (plist-get entry :secret)))
                ;; Handle both string secrets and function secrets
                (when (functionp secret)
                  (setq secret (funcall secret)))
                (cons secret entry)))
            results)))

(defun gptel-gemini--refresh-key-ring ()
  "Refresh the key ring from authinfo."
  (setq gptel-gemini--key-ring (gptel-gemini--fetch-all-keys))
  (setq gptel-gemini--current-key-index 0)
  (message "Gemini key ring refreshed: %d keys available"
           (length gptel-gemini--key-ring)))

(defun gptel-gemini--get-current-key ()
  "Get the currently active API key."
  (unless gptel-gemini--key-ring
    (gptel-gemini--refresh-key-ring))
  (when gptel-gemini--key-ring
    (car (nth gptel-gemini--current-key-index gptel-gemini--key-ring))))

(defun gptel-gemini--rotate-key ()
  "Rotate to the next available API key.
Returns the new key if rotation successful, nil if no more keys available."
  (setq gptel-gemini--current-key-index (1+ gptel-gemini--current-key-index))
  (if (>= gptel-gemini--current-key-index (length gptel-gemini--key-ring))
      (progn
        (message "Gemini key rotation: exhausted all available keys")
        nil)
    (let ((new-key (gptel-gemini--get-current-key)))
      (message "Gemini key rotation: switched to key %d/%d"
               (1+ gptel-gemini--current-key-index)
               (length gptel-gemini--key-ring))
      new-key)))

(defun gptel-gemini--should-rotate-p (info)
  "Determine if we should rotate keys based on error INFO."
  (and gptel-gemini-key-rotation-enabled
       (not gptel-gemini--rotation-in-progress)
       gptel-gemini--key-ring
       (> (length gptel-gemini--key-ring) 1)
       (let ((status (plist-get info :http-status))
             (error-msg (format "%s" (plist-get info :error))))
         (cl-some (lambda (pattern)
                    (or (and status (string-match-p (regexp-quote pattern) status))
                        (string-match-p (regexp-quote pattern) error-msg)))
                  gptel-gemini-key-rotation-errors))))

;;; Backend Integration

(defun gptel-gemini--make-rotating-key-function ()
  "Create a function that returns the current key from the rotating key ring.
This function is suitable for use as the :key parameter in `gptel-make-gemini'."
  (lambda ()
    (or (gptel-gemini--get-current-key)
        (progn
          (gptel-gemini--refresh-key-ring)
          (gptel-gemini--get-current-key)))))

(defun gptel-make-gemini-rotating (name &rest args)
  "Create a Gemini backend with automatic key rotation.
NAME is the backend name.  ARGS are passed to `gptel-make-gemini',
but :key is automatically set to use the rotating key ring.
Example:
  (gptel-make-gemini-rotating \"Gemini-Rotating\"
    :stream t
    :models \\='(gemini-1.5-flash gemini-1.5-pro))"
  (unless gptel-gemini--key-ring
    (gptel-gemini--refresh-key-ring))
  ;; Remove :key from args if provided, we use our own
  (setq args (plist-put args :key (gptel-gemini--make-rotating-key-function)))
  (apply #'gptel-make-gemini name args))

;;; Error Handling Integration

(defun gptel-gemini--handle-error (info)
  "Handle gptel errors by rotating keys if appropriate.
INFO is the plist containing error information."
  (when (gptel-gemini--should-rotate-p info)
    (let ((gptel-gemini--rotation-in-progress t))
      (if-let ((new-key (gptel-gemini--rotate-key)))
          (progn
            ;; Force backend to pick up new key by clearing any cached value
            (when-let ((backend (plist-get info :backend)))
              ;; Update the backend's key slot if it exists
              (when (slot-exists-p backend 'key)
                (setf (slot-value backend 'key)
                      (gptel-gemini--make-rotating-key-function))))
            ;; Retry the request
            (message "Retrying request with rotated key...")
            (run-with-timer 0.5 nil #'gptel-send))
        (message "No more Gemini keys available. Please check your authinfo.")))))

;;; Hook Installation

(defun gptel-gemini-key-rotation-setup ()
  "Set up automatic key rotation hooks."
  (interactive)
  ;; Initialize key ring
  (gptel-gemini--refresh-key-ring)
  ;; not triggered on response with error "code": 429
  (advice-add 'gptel--handle-error :around #'gptel-gemini--check-error-and-rotate)
  (message "Gemini key rotation enabled with %d keys"
           (length gptel-gemini--key-ring)))

;; Method 1: Advice on gptel--handle-error (receives FSM with full info)
(defun gptel-gemini--check-error-and-rotate (orig-fun fsm)
  "Wrap gptel--handle-error to rotate keys on error."
  (let* ((info (gptel-fsm-info fsm))
         (error-data (plist-get info :error)))
    (when (and error-data
               (gptel-gemini--should-rotate-p info))
      (gptel-gemini--handle-error info))
    (funcall orig-fun fsm)))

;; Method 2: Wrap gptel-request to intercept errors
;; (advice-add 'gptel-request :around #'gptel-gemini--wrap-request)
(defun gptel-gemini--wrap-request (orig-fun &rest args)
  "Wrap gptel-request to handle key rotation on errors."
  ;; args is (prompt :key val :key2 val2 ...)
  ;; Extract plist portion (everything after prompt)
  (if (null args)
      (apply orig-fun args)
    (let* ((prompt (car args))
           (plist (cdr args))
           (callback (plist-get args :callback))
           (wrapped-callback
            (lambda (response info)
              (when (and (not (stringp response))
                         (not (eq response t)) ; t means success with streaming
                         (gptel-gemini--should-rotate-p info))
                (gptel-gemini--handle-error info))
              (when callback
                (funcall callback response info))))
           (new-plist (plist-put plist :callback wrapped-callback)))
      (apply orig-fun prompt new-plist))))

;;; Utility Commands

(defun gptel-gemini-force-rotate ()
  "Manually force key rotation."
  (interactive)
  (if-let ((new-key (gptel-gemini--rotate-key)))
      (message "Manually rotated to key %d"
               (1+ gptel-gemini--current-key-index))
    (message "No more keys available")))

(defun gptel-gemini-reset-key-ring ()
  "Reset key ring to start from the first key again."
  (interactive)
  (setq gptel-gemini--current-key-index 0)
  (message "Key ring reset to key 1"))

(provide 'gptel-gemini-key-rotation)
;;; gptel-gemini-key-rotation.el ends here