pyrate_limiter.buckets.sqlite_bucket module

Bucket implementation using SQLite

class pyrate_limiter.buckets.sqlite_bucket.Queries

Bases: object

COUNT_ALL = "SELECT COUNT(*) FROM '{table}'"

COUNT_BEFORE_INSERT = "\n    SELECT :interval{index} as interval, COUNT(*) FROM '{table}'\n    WHERE item_timestamp >= :current_timestamp - :interval{index}\n    "

COUNT_BEFORE_LEAK = "SELECT COUNT(*) FROM '{table}' WHERE item_timestamp < {current_timestamp} - {interval}"

CREATE_BUCKET_TABLE = "\n    CREATE TABLE IF NOT EXISTS '{table}' (\n        name VARCHAR,\n        item_timestamp INTEGER\n    )\n    "

CREATE_INDEX_ON_TIMESTAMP = "\n    CREATE INDEX IF NOT EXISTS '{index_name}' ON '{table_name}' (item_timestamp)\n    "

DROP_INDEX = "DROP INDEX IF EXISTS '{index}'"

DROP_TABLE = "DROP TABLE IF EXISTS '{table}'"

FLUSH = "DELETE FROM '{table}'"

GET_ALL_ITEM = "SELECT * FROM '{table}' ORDER BY item_timestamp ASC"

GET_FIRST_ITEM = "SELECT name, item_timestamp FROM '{table}' ORDER BY item_timestamp ASC"

GET_LAG = "\n    SELECT (strftime ('%s', 'now') || substr(strftime ('%f', 'now'), 4)) - (\n    SELECT item_timestamp\n    FROM '{table}'\n    ORDER BY item_timestamp\n    ASC\n    LIMIT 1\n    )\n    "

LEAK = 'DELETE FROM "{table}" WHERE rowid IN (\n    SELECT rowid FROM "{table}" ORDER BY item_timestamp ASC LIMIT {count});'

PEEK = 'SELECT * FROM "{table}" ORDER BY item_timestamp DESC LIMIT 1 OFFSET {count}'

PUT_ITEM = "\n    INSERT INTO '{table}' (name, item_timestamp) VALUES %s\n    "

class pyrate_limiter.buckets.sqlite_bucket.SQLiteBucket(rates, conn, table, lock=None)

Bases: AbstractBucket

For sqlite bucket, we are using the sql time function as the clock item’s timestamp wont matter here

close()

Release any resources held by the bucket.

Subclasses may override this method to perform any necessary cleanup (e.g., closing files, network connections, or releasing locks) when the bucket is no longer needed.

conn

count()

Count number of items in the bucket

Return type:

int

flush()

Flush the whole bucket - Must remove failing-rate after flushing

Return type:

None

full_count_query

classmethod init_from_file(rates, table='rate_bucket', db_path=None, create_new_table=True, use_file_lock=False)

Return type:

SQLiteBucket

leak(current_timestamp=None)

Leaking/clean up bucket

Return type:

int

limiter_lock()

An additional lock to be used by Limiter in-front of the thread lock. Intended for multiprocessing environments where a thread lock is insufficient.

lock

now()

Retrieve current timestamp from the clock backend.

peek(index)

Peek at the rate-item at a specific index in latest-to-earliest order NOTE: The reason we cannot peek from the start of the queue(earliest-to-latest) is we can’t really tell how many outdated items are still in the queue

Return type:

Optional[RateItem]

put(item)

Put an item (typically the current time) in the bucket return true if successful, otherwise false

Return type:

bool

rates

table

use_limiter_lock

class pyrate_limiter.buckets.sqlite_bucket.SQLiteClock(conn)

Bases: AbstractClock

Get timestamp using SQLite as remote clock backend

__init__(conn)

In multiprocessing cases, use the bucket, so that a shared lock is used.

classmethod default()

lock

now()

Get time as of now, in milliseconds

Return type:

int

time_query = "SELECT CAST(ROUND((julianday('now') - 2440587.5)*86400000) As INTEGER)"