docs: add example

Author: karel-rehor

Examples/query_async.py

@@ -0,0 +1,87 @@
+import asyncio
+import random
+import time
+
+import pandas
+
+from influxdb_client_3 import InfluxDBClient3
+
+from config import Config
+
+
+async def fibio(iterations, grit=0.5):
+    """
+    example coroutine to run parallel with query_async
+    :param iterations:
+    :param grit:
+    :return:
+    """
+    n0 = 1
+    n1 = 1
+    vals = [n0, n1]
+    for _ in range(iterations):
+        val = n0 + n1
+        n0 = n1
+        n1 = val
+        print(val)
+        vals.append(val)
+        await asyncio.sleep(grit)
+    return vals
+
+
+def write_data(client: InfluxDBClient3, measurement):
+    """
+    Synchronous write - only for preparing data
+    :param client:
+    :param measurement:
+    :return:
+    """
+    ids = ['s3b1', 'dq41', 'sgw22']
+    lp_template = f"{measurement},id=%s speed=%f,alt=%f,bearing=%f %d"
+    data_size = 10
+    data = []
+    interval = 10 * 1_000_000_000
+    ts = time.time_ns() - (interval * data_size)
+    for _ in range(data_size):
+        data.append(lp_template % (ids[random.randint(0, len(ids) - 1)],
+                                   random.random() * 300,
+                                   random.random() * 2000,
+                                   random.random() * 360, ts))
+        ts += interval
+
+    client.write(data)
+
+
+async def query_data(client: InfluxDBClient3, measurement):
+    """
+    Query asynchronously - should not block other coroutines
+    :param client:
+    :param measurement:
+    :return:
+    """
+    query = f"SELECT * FROM \"{measurement}\" WHERE time >= now() - interval '5 minutes' ORDER BY time DESC"
+    print(f"query start:    {pandas.Timestamp(time.time_ns())}")
+    table = await client.query_async(query)
+    print(f"query returned: {pandas.Timestamp(time.time_ns())}")
+    return table.to_pandas()
+
+
+async def main():
+    config = Config()
+    client = InfluxDBClient3(
+        host=config.host,
+        token=config.token,
+        database=config.database,
+        org=config.org
+    )
+    measurement = 'example_uav'
+    write_data(client, measurement)
+
+    # run both coroutines simultaneously
+    result = await asyncio.gather(fibio(10, 0.2),query_data(client, measurement))
+    print(f"fibio sequence = {result[0]}")
+    print(f"data set =\n{result[1]}")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())