fix: multiprocessing example (#664)

* fix: multiprocessing example

* docs: update CHANGELOG.md

Author: bednar

CHANGELOG.md

@@ -1,5 +1,8 @@
 ## 1.46.0 [unreleased]
 
+### Examples:
+1. [#664](https://github.com/influxdata/influxdb-client-python/pull/664/): Multiprocessing example uses new source of data
+
 ## 1.45.0 [2024-08-12]
 
 ### Bug Fixes

examples/import_data_set_multiprocessing.py

@@ -4,6 +4,7 @@
 https://github.com/toddwschneider/nyc-taxi-data
 """
 import concurrent.futures
+import gzip
 import io
 import multiprocessing
 from collections import OrderedDict
@@ -92,10 +93,10 @@ def parse_row(row: OrderedDict):
 
     return Point("taxi-trip-data") \
         .tag("dispatching_base_num", row['dispatching_base_num']) \
-        .tag("PULocationID", row['PULocationID']) \
-        .tag("DOLocationID", row['DOLocationID']) \
+        .tag("PULocationID", row['PUlocationID']) \
+        .tag("DOLocationID", row['DOlocationID']) \
         .tag("SR_Flag", row['SR_Flag']) \
-        .field("dropoff_datetime", row['dropoff_datetime']) \
+        .field("dropoff_datetime", row['dropOff_datetime']) \
         .time(row['pickup_datetime']) \
         .to_line_protocol()
 
@@ -113,7 +114,7 @@ def parse_rows(rows, total_size):
     counter_.value += len(_parsed_rows)
     if counter_.value % 10_000 == 0:
         print('{0:8}{1}'.format(counter_.value, ' - {0:.2f} %'
-                                .format(100 * float(progress_.value) / float(int(total_size))) if total_size else ""))
+                                .format(float(progress_.value) / float(int(total_size))) if total_size else ""))
         pass
 
     queue_.put(_parsed_rows)
@@ -141,80 +142,80 @@ def init_counter(counter, progress, queue):
     progress_ = Value('i', 0)
     startTime = datetime.now()
 
-    url = "https://s3.amazonaws.com/nyc-tlc/trip+data/fhv_tripdata_2019-01.csv"
-    # url = "file:///Users/bednar/Developer/influxdata/influxdb-client-python/examples/fhv_tripdata_2019-01.csv"
+    url = "https://github.com/DataTalksClub/nyc-tlc-data/releases/download/fhv/fhv_tripdata_2019-01.csv.gz"
 
     """
     Open URL and for stream data 
     """
     response = urlopen(url)
-    if response.headers:
-        content_length = response.headers['Content-length']
-    io_wrapper = ProgressTextIOWrapper(response)
-    io_wrapper.progress = progress_
+    # we can't get content length from response because the gzip stream content length is unknown
+    # so we set it to this value, just for progress display
+    content_length = 23143223
 
     """
-    Start writer as a new process
+    Open GZIP stream
     """
-    writer = InfluxDBWriter(queue_)
-    writer.start()
+    with gzip.open(response, 'rb') as stream:
+        io_wrapper = ProgressTextIOWrapper(stream, encoding='utf-8')
+        io_wrapper.progress = progress_
 
-    """
-    Create process pool for parallel encoding into LineProtocol
-    """
-    cpu_count = multiprocessing.cpu_count()
-    with concurrent.futures.ProcessPoolExecutor(cpu_count, initializer=init_counter,
-                                                initargs=(counter_, progress_, queue_)) as executor:
         """
-        Converts incoming HTTP stream into sequence of LineProtocol
+        Start writer as a new process
         """
-        data = rx \
-            .from_iterable(DictReader(io_wrapper)) \
-            .pipe(ops.buffer_with_count(10_000),
-                  # Parse 10_000 rows into LineProtocol on subprocess
-                  ops.flat_map(lambda rows: executor.submit(parse_rows, rows, content_length)))
+        writer = InfluxDBWriter(queue_)
+        writer.start()
 
         """
-        Write data into InfluxDB
+        Create process pool for parallel encoding into LineProtocol
         """
-        data.subscribe(on_next=lambda x: None, on_error=lambda ex: print(f'Unexpected error: {ex}'))
-
-    """
-    Terminate Writer
-    """
-    queue_.put(None)
-    queue_.join()
+        cpu_count = multiprocessing.cpu_count()
+        with concurrent.futures.ProcessPoolExecutor(cpu_count, initializer=init_counter,
+                                                    initargs=(counter_, progress_, queue_)) as executor:
+            """
+            Converts incoming HTTP stream into sequence of LineProtocol
+            """
+            data = rx \
+                .from_iterable(DictReader(io_wrapper)) \
+                .pipe(ops.buffer_with_count(10_000),
+                      # Parse 10_000 rows into LineProtocol on subprocess
+                      ops.map(lambda rows: executor.submit(parse_rows, rows, content_length)))
+
+            """
+            Write data into InfluxDB
+            """
+            data.subscribe(on_next=lambda x: None, on_error=lambda ex: print(f'Unexpected error: {ex}'))
 
-    print()
-    print(f'Import finished in: {datetime.now() - startTime}')
-    print()
-
-    """
-    Querying 10 pickups from dispatching 'B00008'
-    """
-    query = 'from(bucket:"my-bucket")' \
-            '|> range(start: 2019-01-01T00:00:00Z, stop: now()) ' \
-            '|> filter(fn: (r) => r._measurement == "taxi-trip-data")' \
-            '|> filter(fn: (r) => r.dispatching_base_num == "B00008")' \
-            '|> pivot(rowKey:["_time"], columnKey: ["_field"], valueColumn: "_value")' \
-            '|> rename(columns: {_time: "pickup_datetime"})' \
-            '|> drop(columns: ["_start", "_stop"])|> limit(n:10, offset: 0)'
-
-    client = InfluxDBClient(url="http://localhost:8086", token="my-token", org="my-org", debug=False)
-    result = client.query_api().query(query=query)
+        """
+        Terminate Writer
+        """
+        queue_.put(None)
+        queue_.join()
 
-    """
-    Processing results
-    """
-    print()
-    print("=== Querying 10 pickups from dispatching 'B00008' ===")
-    print()
-    for table in result:
-        for record in table.records:
-            print(
-                f'Dispatching: {record["dispatching_base_num"]} pickup: {record["pickup_datetime"]} dropoff: {record["dropoff_datetime"]}')
+        print()
+        print(f'Import finished in: {datetime.now() - startTime}')
+        print()
 
-    """
-    Close client
-    """
-    client.close()
+        """
+        Querying 10 pickups from dispatching 'B00008'
+        """
+        query = 'from(bucket:"my-bucket")' \
+                '|> range(start: 2019-01-01T00:00:00Z, stop: now()) ' \
+                '|> filter(fn: (r) => r._measurement == "taxi-trip-data")' \
+                '|> filter(fn: (r) => r.dispatching_base_num == "B00008")' \
+                '|> pivot(rowKey:["_time"], columnKey: ["_field"], valueColumn: "_value")' \
+                '|> rename(columns: {_time: "pickup_datetime"})' \
+                '|> drop(columns: ["_start", "_stop"])|> limit(n:10, offset: 0)'
+
+        with InfluxDBClient(url="http://localhost:8086", token="my-token", org="my-org", debug=False) as client:
+            result = client.query_api().query(query=query)
+
+            """
+            Processing results
+            """
+            print()
+            print("=== Querying 10 pickups from dispatching 'B00008' ===")
+            print()
+            for table in result:
+                for record in table.records:
+                    print(
+                        f'Dispatching: {record["dispatching_base_num"]} pickup: {record["pickup_datetime"]} dropoff: {record["dropoff_datetime"]}')