Apache Pulsar Edge IoT Applications with Python for TVOC

Tim Spann
12 min readApr 27, 2022

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FLiP-Py-Pi-GasThermal

Apache Pulsar, Python, Raspberry Pi, Gas Sensor + Thermal Camera Sensors, Apache Flink, Trino/Presto SQL

Sensors

  • Pimoroni BreakoutGarden: SGP30
  • Sensiron SGP30 TVOC and eCO2 sensor (datasheet)
  • TVOC sensing from 0–60,000 ppb (parts per billion)
  • CO2 sensing from 400 to 60,000 ppm (parts per million)
  • Pimoroni BreakoutGarden: MLX90640 Thermal Camera

Architecture

Build

bin/pulsar-admin topics create persistent://public/default/garden3bin/pulsar-client consume "persistent://public/default/garden3" -s "garden3reader" -n 0class Garden(Record):
cpu = Float()
diskusage = String()
endtime = String()
equivalentco2ppm = String()
host = String()
hostname = String()
ipaddress = String()
macaddress = String()
memory = Float()
rowid = String()
runtime = Integer()
starttime = String()
systemtime = String()
totalvocppb = String()
ts = Integer()
uuid = String()
----- got message -----
key:[garden3_uuid_yvs_20220306191528], properties:[], content:{
"cpu": 0.0,
"diskusage": "103496.6 MB",
"endtime": "1646594128.2460103",
"equivalentco2ppm": " 413",
"host": "garden3",
"hostname": "garden3",
"ipaddress": "192.168.1.198",
"macaddress": "dc:a6:32:32:98:20",
"memory": 9.2,
"rowid": "20220306191528_707b34d4-7299-4233-a495-d2d97393e834",
"runtime": 0,
"starttime": "03/06/2022 14:15:28",
"systemtime": "03/06/2022 14:15:29",
"totalvocppb": " 5",
"ts": 1646594129,
"uuid": "garden3_uuid_yvs_20220306191528"
}
presto> select * from pulsar."public/default"."garden3";
cpu | diskusage | endtime | equivalentco2ppm | host | hostname | ipaddress | macaddress | memory | rowid | runtime |
-----+-------------+--------------------+------------------+---------+----------+---------------+-------------------+--------+-----------------------------------------------------+---------+------
6.5 | 103496.5 MB | 1646594650.7116666 | 418 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192410_197b6b0c-b86c-4191-9e9c-11777767825e | 0 | 03/06
6.7 | 103496.5 MB | 1646594651.7441382 | 418 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192411_4dab3212-423b-46a9-ae39-b10eb363336d | 0 | 03/06
1.3 | 103496.5 MB | 1646594652.7764313 | 421 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192412_d24a819b-4ca1-489a-9683-da48bc37185c | 0 | 03/06
0.2 | 103496.5 MB | 1646594653.810233 | 421 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192413_f4e43177-2486-4a36-b27a-903028d6aacf | 0 | 03/06
0.0 | 103496.5 MB | 1646594654.8467774 | 416 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192414_558d3db8-725a-46ec-ad1f-89f8067142f8 | 0 | 03/06
0.0 | 103496.5 MB | 1646594655.880628 | 420 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192415_1eeea533-7f7e-4945-a089-d4b2f8681e14 | 0 | 03/06
0.0 | 103496.5 MB | 1646594656.9145741 | 418 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192416_d7d8c6ea-2adf-4704-8f49-3108a7328f26 | 0 | 03/06
0.0 | 103496.5 MB | 1646594657.9489982 | 425 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192417_c71cbb6e-c59f-4855-84ae-b796fd3d7a76 | 0 | 03/06
0.0 | 103496.5 MB | 1646594658.9828157 | 420 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192418_c14204dd-4c1c-4e76-a272-8ddecd11a97c | 0 | 03/06
0.0 | 103496.5 MB | 1646594660.0187812 | 420 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192419_c7583063-06e0-4601-806a-96619b6bb136 | 0 | 03/06
0.0 | 103496.5 MB | 1646594661.0531507 | 428 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192421_57e4a8ed-af6f-4dd0-b143-f29f1a211fdb | 0 | 03/06
0.0 | 103496.5 MB | 1646594662.087301 | 421 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192422_cf2ce36e-c996-41ac-baec-db292cffdd37 | 0 | 03/06
6.2 | 103496.5 MB | 1646594663.1214898 | 415 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192423_30b13428-ac2e-4929-b9f5-c4c3fbc3312a | 0 | 03/06
6.5 | 103496.5 MB | 1646594664.1541135 | 424 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192424_d1517315-85fa-4923-b634-9b673c5b20ba | 0 | 03/06
3.6 | 103496.5 MB | 1646594665.1890867 | 417 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192425_3984b0bc-a92e-4458-834c-e65259bb7a4d | 0 | 03/06
0.0 | 103496.5 MB | 1646594666.221572 | 422 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192426_e0debd83-47e8-43f7-8ec5-cf0dbc27b87e | 0 | 03/06
0.0 | 103496.5 MB | 1646594667.2555919 | 424 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192427_6ec920e7-56d2-4730-bddc-e18592cf1210 | 0 | 03/06
0.0 | 103496.5 MB | 1646594668.2893167 | 428 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192428_434b4458-6f89-4161-b967-f29796d8bf5d | 0 | 03/06
0.0 | 103496.5 MB | 1646594669.3234618 | 426 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192429_5bb29c2e-d078-405d-b8f6-967ea4753b3f | 0 | 03/06
0.0 | 103496.5 MB | 1646594670.359024 | 421 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192430_05b86f6b-4d28-497c-acd6-d14f7ce27157 | 0 | 03/06
0.0 | 103496.5 MB | 1646594671.392967 | 432 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192431_b7a2955a-6f39-4439-8eb9-27d7a2633836 | 0 | 03/06
0.0 | 103496.5 MB | 1646594672.4271743 | 426 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192432_29861384-fc30-4deb-bc1d-b7f2d27ef89d | 0 | 03/06
0.0 | 103496.5 MB | 1646594673.4611707 | 424 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192433_25435335-39fe-4294-b913-95c63537a743 | 0 | 03/06
0.0 | 103496.5 MB | 1646594674.4951062 | 424 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192434_a52a90e8-b11c-467b-b87f-936432bc8988 | 0 | 03/06
3.3 | 103496.5 MB | 1646594675.531778 | 436 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192435_48bab6a9-9f2e-443b-9fed-f096f6c24ebd | 0 | 03/06
6.5 | 103496.5 MB | 1646594676.5642908 | 433 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192436_761f79dc-06f6-4ed3-8062-5227b6842b77 | 0 | 03/06
6.2 | 103496.5 MB | 1646594677.5965276 | 421 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192437_6d8d49c9-0519-4825-b6b7-ed435e9fe747 | 0 | 03/06
0.0 | 103496.5 MB | 1646594678.6290672 | 423 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192438_a920872d-f152-4b18-94a7-b4dfe5641482 | 0 | 03/06
0.0 | 103496.5 MB | 1646594679.6629703 | 418 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192439_032ce574-10f6-4b50-b5e8-102b466af65a | 0 | 03/06
0.0 | 103496.5 MB | 1646594680.699419 | 420 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192440_cde6f78a-d028-4f87-a95b-156bac0ee0c2 | 0 | 03/06
0.0 | 103496.5 MB | 1646594681.7338123 | 424 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192441_7400689a-6974-4ff2-a688-96c317d45d03 | 0 | 03/06
0.0 | 103496.5 MB | 1646594682.767776 | 417 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192442_46696fa7-295c-4fe6-bf49-8d8405e21cf5 | 0 | 03/06
0.0 | 103496.5 MB | 1646594683.8017883 | 420 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192443_4de9f79c-0169-49d6-b337-fb57dcb5cf7e | 0 | 03/06
0.0 | 103496.5 MB | 1646594684.8360054 | 422 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192444_63081ac4-2c87-462d-bc16-ab506e9c6db2 | 0 | 03/06
0.0 | 103496.5 MB | 1646594685.8720167 | 420 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192445_fee13e36-26c6-4f06-894c-8b96cb0f3bae | 0 | 03/06
0.0 | 103496.5 MB | 1646594686.90594 | 431 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192446_8aaa423d-bfe3-43e8-8653-d554c2afb8d6 | 0 | 03/06
0.8 | 103496.4 MB | 1646594687.939747 | 416 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192447_bfe339cd-3fb4-4d2a-b612-3a2363e1b83b | 0 | 03/06
6.5 | 103496.4 MB | 1646594688.9728699 | 424 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192448_8809fc3e-75f8-4aca-a141-6e5d4872b0de | 0 | 03/06
6.5 | 103496.4 MB | 1646594690.0051649 | 412 | garden3 | garden3 | 192.168.1.198 | dc:a6:32:32:98:20 | 9.2 | 20220306192449_0d0b4b62-0321-4bcd-952b-14607333d9f5 | 0 | 03/06
presto> desc pulsar."public/default"."garden3";
Column | Type | Extra | Comment
-------------------+-----------+-------+-----------------------------------------------------------------------------
cpu | real | | ["null","float"]
diskusage | varchar | | ["null","string"]
endtime | varchar | | ["null","string"]
equivalentco2ppm | varchar | | ["null","string"]
host | varchar | | ["null","string"]
hostname | varchar | | ["null","string"]
ipaddress | varchar | | ["null","string"]
macaddress | varchar | | ["null","string"]
memory | real | | ["null","float"]
rowid | varchar | | ["null","string"]
runtime | integer | | ["null","int"]
starttime | varchar | | ["null","string"]
systemtime | varchar | | ["null","string"]
totalvocppb | varchar | | ["null","string"]
ts | integer | | ["null","int"]
uuid | varchar | | ["null","string"]
__partition__ | integer | | The partition number which the message belongs to
__event_time__ | timestamp | | Application defined timestamp in milliseconds of when the event occurred
__publish_time__ | timestamp | | The timestamp in milliseconds of when event as published
__message_id__ | varchar | | The message ID of the message used to generate this row
__sequence_id__ | bigint | | The sequence ID of the message used to generate this row
__producer_name__ | varchar | | The name of the producer that publish the message used to generate this row
__key__ | varchar | | The partition key for the topic
__properties__ | varchar | | User defined properties

Presto/Trino gives us access to all that tasty meta data for each message/event/row/record/thing/data stuff. All with special names to help prevent collisions.

Meta Data

  • partition — if we have a partitioned topic, which partition does this message belong to.
  • event_time — you know what time it is! Timestamp in ms for event action.
  • publish_time — when was this message published to the topic?
  • message_id — unique id for this message
  • sequence_id — ordering information for this message
  • producer_name — who sent me this?
  • key — did you assign a key like I asked you to?
  • properties — all those extra fields you added around the payload

Spark Structured Streaming

val dfPulsar = spark.readStream.format("pulsar").option("service.url", "pulsar://localhost:6650").option("admin.url", "http://localhost:8080").option("topic", "persistent://public/default/garden3").load()
dfPulsar.printSchema()
val pQuery = dfPulsar.selectExpr("*").writeStream.format("parquet").option("truncate", false) .option("checkpointLocation", "/tmp/checkpoint").option("path", "/opt/demo/gasthermal").start()

pQuery.explain()
pQuery.awaitTermination()
pQuery.stop()
// can be "orc", "json", "csv", etc.

Show Me The Data

We can visualize data from Apache Pulsar by consuming it through the web sockets interface in a simple JQuery Single Page Web Application like below.

Example Parquet Files

pip3 install parquet-tools -Uparquet-tools inspect part-00000-b7e1f8dc-956d-4130-bc59-7b1435e41391-c000.snappy.parquet############ file meta data ############
created_by: parquet-mr version 1.12.1 (build 2a5c06c58fa987f85aa22170be14d927d5ff6e7d)
num_columns: 23
num_rows: 1
num_row_groups: 1
format_version: 1.0
serialized_size: 5071
############ Columns ############
cpu
diskusage
endtime
equivalentco2ppm
host
hostname
ipaddress
macaddress
memory
rowid
runtime
starttime
systemtime
totalvocppb
ts
uuid
__key
__topic
__messageId
__publishTime
__eventTime
key
value
############ Column(cpu) ############
name: cpu
path: cpu
max_definition_level: 1
max_repetition_level: 0
physical_type: FLOAT
logical_type: None
converted_type (legacy): NONE
############ Column(diskusage) ############
name: diskusage
path: diskusage
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(endtime) ############
name: endtime
path: endtime
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(equivalentco2ppm) ############
name: equivalentco2ppm
path: equivalentco2ppm
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(host) ############
name: host
path: host
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(hostname) ############
name: hostname
path: hostname
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(ipaddress) ############
name: ipaddress
path: ipaddress
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(macaddress) ############
name: macaddress
path: macaddress
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(memory) ############
name: memory
path: memory
max_definition_level: 1
max_repetition_level: 0
physical_type: FLOAT
logical_type: None
converted_type (legacy): NONE
############ Column(rowid) ############
name: rowid
path: rowid
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(runtime) ############
name: runtime
path: runtime
max_definition_level: 1
max_repetition_level: 0
physical_type: INT32
logical_type: None
converted_type (legacy): NONE
############ Column(starttime) ############
name: starttime
path: starttime
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(systemtime) ############
name: systemtime
path: systemtime
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(totalvocppb) ############
name: totalvocppb
path: totalvocppb
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(ts) ############
name: ts
path: ts
max_definition_level: 1
max_repetition_level: 0
physical_type: INT32
logical_type: None
converted_type (legacy): NONE
############ Column(uuid) ############
name: uuid
path: uuid
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(__key) ############
name: __key
path: __key
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: None
converted_type (legacy): NONE
############ Column(__topic) ############
name: __topic
path: __topic
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(__messageId) ############
name: __messageId
path: __messageId
max_definition_level: 1
max_repetition_level: 0
physical_type: BYTE_ARRAY
logical_type: None
converted_type (legacy): NONE
############ Column(__publishTime) ############
name: __publishTime
path: __publishTime
max_definition_level: 1
max_repetition_level: 0
physical_type: INT96
logical_type: None
converted_type (legacy): NONE
############ Column(__eventTime) ############
name: __eventTime
path: __eventTime
max_definition_level: 1
max_repetition_level: 0
physical_type: INT96
logical_type: None
converted_type (legacy): NONE
############ Column(key) ############
name: key
path: __messageProperties.key_value.key
max_definition_level: 2
max_repetition_level: 1
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8
############ Column(value) ############
name: value
path: __messageProperties.key_value.value
max_definition_level: 3
max_repetition_level: 1
physical_type: BYTE_ARRAY
logical_type: String
converted_type (legacy): UTF8

Flink

CREATE CATALOG pulsar WITH (
'type' = 'pulsar',
'service-url' = 'pulsar://pulsar1:6650',
'admin-url' = 'http://pulsar1:8080',
'format' = 'json'
);
USE CATALOG pulsar;SHOW TABLES;Flink SQL> describe garden3;
+------------------+--------+------+-----+--------+-----------+
| name | type | null | key | extras | watermark |
+------------------+--------+------+-----+--------+-----------+
| cpu | FLOAT | true | | | |
| diskusage | STRING | true | | | |
| endtime | STRING | true | | | |
| equivalentco2ppm | STRING | true | | | |
| host | STRING | true | | | |
| hostname | STRING | true | | | |
| ipaddress | STRING | true | | | |
| macaddress | STRING | true | | | |
| memory | FLOAT | true | | | |
| rowid | STRING | true | | | |
| runtime | INT | true | | | |
| starttime | STRING | true | | | |
| systemtime | STRING | true | | | |
| totalvocppb | STRING | true | | | |
| ts | INT | true | | | |
| uuid | STRING | true | | | |
+------------------+--------+------+-----+--------+-----------+
16 rows in set
select equivalentco2ppm, totalvocppb, cpu, starttime, systemtime, ts, cpu, diskusage, endtime, memory, uuid from garden3;select max(equivalentco2ppm) as MaxCO2, max(totalvocppb) as MaxVocPPB from garden3;
// TODOAdd your own table publishTime TIMESTAMP(3) METADATA,
WATERMARK FOR publishTime AS publishTime - INTERVAL '5' SECOND

Apache NiFi (FLiPN)

  • Choose a processor from the palette
  • Consume messages from Apache Pulsar
  • Full Apache NiFi Data Flow with Apache Pulsar and MongoDB

MongoDB

mongo -u username1 -p password1 --authenticationDatabase admin pulsar1:27017/inventoryshow databasesdb.createCollection("garden3")show collectionsdb.garden3.find().pretty(){
"_id" : ObjectId("622f7315f99b9a338d60592f"),
"cpu" : 0,
"diskusage" : "101615.9 MB",
"endtime" : "1647276083.2033532",
"equivalentco2ppm" : " 407",
"host" : "garden3",
"hostname" : "garden3",
"ipaddress" : "192.168.1.199",
"macaddress" : "dc:a6:32:32:98:20",
"memory" : 8.8,
"rowid" : "20220314164123_0e19c5e6-45f5-405e-bd93-9aed05b37630",
"runtime" : 0,
"starttime" : "03/14/2022 12:41:23",
"systemtime" : "03/14/2022 12:41:24",
"totalvocppb" : " 5",
"ts" : 1647276084,
"uuid" : "garden3_uuid_xrl_20220314164123"
}

References

Additional Heat Images

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Tim Spann

Principal Developer Advocate, Zilliz. Milvus, Attu, Towhee, GenAI, Big Data, IoT, Deep Learning, Streaming, Machine Learning. https://www.datainmotion.dev/