Skip to content

Commit 502a8eb

Browse files
findinpathfindinpath
committed
Initial commit
0 parents  commit 502a8eb

Some content is hidden

Large Commits have some content hidden by default. Use the searchbox below for content that may be hidden.

58 files changed

+10173
-0
lines changed

‎.gitignore

+19
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
1+
# Build products
2+
target/
3+
4+
# IntelliJ data
5+
*.iml
6+
.idea/
7+
.ipr
8+
9+
# Documentation build output
10+
/docs/_build
11+
12+
.DS_Store
13+
14+
derby.log
15+
16+
# Test databases
17+
__test_database_*
18+
test.sqlite
19+
*.db-journal

‎LICENSE

+201
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,201 @@
1+
Apache License
2+
Version 2.0, January 2004
3+
http://www.apache.org/licenses/
4+
5+
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
6+
7+
1. Definitions.
8+
9+
"License" shall mean the terms and conditions for use, reproduction,
10+
and distribution as defined by Sections 1 through 9 of this document.
11+
12+
"Licensor" shall mean the copyright owner or entity authorized by
13+
the copyright owner that is granting the License.
14+
15+
"Legal Entity" shall mean the union of the acting entity and all
16+
other entities that control, are controlled by, or are under common
17+
control with that entity. For the purposes of this definition,
18+
"control" means (i) the power, direct or indirect, to cause the
19+
direction or management of such entity, whether by contract or
20+
otherwise, or (ii) ownership of fifty percent (50%) or more of the
21+
outstanding shares, or (iii) beneficial ownership of such entity.
22+
23+
"You" (or "Your") shall mean an individual or Legal Entity
24+
exercising permissions granted by this License.
25+
26+
"Source" form shall mean the preferred form for making modifications,
27+
including but not limited to software source code, documentation
28+
source, and configuration files.
29+
30+
"Object" form shall mean any form resulting from mechanical
31+
transformation or translation of a Source form, including but
32+
not limited to compiled object code, generated documentation,
33+
and conversions to other media types.
34+
35+
"Work" shall mean the work of authorship, whether in Source or
36+
Object form, made available under the License, as indicated by a
37+
copyright notice that is included in or attached to the work
38+
(an example is provided in the Appendix below).
39+
40+
"Derivative Works" shall mean any work, whether in Source or Object
41+
form, that is based on (or derived from) the Work and for which the
42+
editorial revisions, annotations, elaborations, or other modifications
43+
represent, as a whole, an original work of authorship. For the purposes
44+
of this License, Derivative Works shall not include works that remain
45+
separable from, or merely link (or bind by name) to the interfaces of,
46+
the Work and Derivative Works thereof.
47+
48+
"Contribution" shall mean any work of authorship, including
49+
the original version of the Work and any modifications or additions
50+
to that Work or Derivative Works thereof, that is intentionally
51+
submitted to Licensor for inclusion in the Work by the copyright owner
52+
or by an individual or Legal Entity authorized to submit on behalf of
53+
the copyright owner. For the purposes of this definition, "submitted"
54+
means any form of electronic, verbal, or written communication sent
55+
to the Licensor or its representatives, including but not limited to
56+
communication on electronic mailing lists, source code control systems,
57+
and issue tracking systems that are managed by, or on behalf of, the
58+
Licensor for the purpose of discussing and improving the Work, but
59+
excluding communication that is conspicuously marked or otherwise
60+
designated in writing by the copyright owner as "Not a Contribution."
61+
62+
"Contributor" shall mean Licensor and any individual or Legal Entity
63+
on behalf of whom a Contribution has been received by Licensor and
64+
subsequently incorporated within the Work.
65+
66+
2. Grant of Copyright License. Subject to the terms and conditions of
67+
this License, each Contributor hereby grants to You a perpetual,
68+
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
69+
copyright license to reproduce, prepare Derivative Works of,
70+
publicly display, publicly perform, sublicense, and distribute the
71+
Work and such Derivative Works in Source or Object form.
72+
73+
3. Grant of Patent License. Subject to the terms and conditions of
74+
this License, each Contributor hereby grants to You a perpetual,
75+
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
76+
(except as stated in this section) patent license to make, have made,
77+
use, offer to sell, sell, import, and otherwise transfer the Work,
78+
where such license applies only to those patent claims licensable
79+
by such Contributor that are necessarily infringed by their
80+
Contribution(s) alone or by combination of their Contribution(s)
81+
with the Work to which such Contribution(s) was submitted. If You
82+
institute patent litigation against any entity (including a
83+
cross-claim or counterclaim in a lawsuit) alleging that the Work
84+
or a Contribution incorporated within the Work constitutes direct
85+
or contributory patent infringement, then any patent licenses
86+
granted to You under this License for that Work shall terminate
87+
as of the date such litigation is filed.
88+
89+
4. Redistribution. You may reproduce and distribute copies of the
90+
Work or Derivative Works thereof in any medium, with or without
91+
modifications, and in Source or Object form, provided that You
92+
meet the following conditions:
93+
94+
(a) You must give any other recipients of the Work or
95+
Derivative Works a copy of this License; and
96+
97+
(b) You must cause any modified files to carry prominent notices
98+
stating that You changed the files; and
99+
100+
(c) You must retain, in the Source form of any Derivative Works
101+
that You distribute, all copyright, patent, trademark, and
102+
attribution notices from the Source form of the Work,
103+
excluding those notices that do not pertain to any part of
104+
the Derivative Works; and
105+
106+
(d) If the Work includes a "NOTICE" text file as part of its
107+
distribution, then any Derivative Works that You distribute must
108+
include a readable copy of the attribution notices contained
109+
within such NOTICE file, excluding those notices that do not
110+
pertain to any part of the Derivative Works, in at least one
111+
of the following places: within a NOTICE text file distributed
112+
as part of the Derivative Works; within the Source form or
113+
documentation, if provided along with the Derivative Works; or,
114+
within a display generated by the Derivative Works, if and
115+
wherever such third-party notices normally appear. The contents
116+
of the NOTICE file are for informational purposes only and
117+
do not modify the License. You may add Your own attribution
118+
notices within Derivative Works that You distribute, alongside
119+
or as an addendum to the NOTICE text from the Work, provided
120+
that such additional attribution notices cannot be construed
121+
as modifying the License.
122+
123+
You may add Your own copyright statement to Your modifications and
124+
may provide additional or different license terms and conditions
125+
for use, reproduction, or distribution of Your modifications, or
126+
for any such Derivative Works as a whole, provided Your use,
127+
reproduction, and distribution of the Work otherwise complies with
128+
the conditions stated in this License.
129+
130+
5. Submission of Contributions. Unless You explicitly state otherwise,
131+
any Contribution intentionally submitted for inclusion in the Work
132+
by You to the Licensor shall be under the terms and conditions of
133+
this License, without any additional terms or conditions.
134+
Notwithstanding the above, nothing herein shall supersede or modify
135+
the terms of any separate license agreement you may have executed
136+
with Licensor regarding such Contributions.
137+
138+
6. Trademarks. This License does not grant permission to use the trade
139+
names, trademarks, service marks, or product names of the Licensor,
140+
except as required for reasonable and customary use in describing the
141+
origin of the Work and reproducing the content of the NOTICE file.
142+
143+
7. Disclaimer of Warranty. Unless required by applicable law or
144+
agreed to in writing, Licensor provides the Work (and each
145+
Contributor provides its Contributions) on an "AS IS" BASIS,
146+
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
147+
implied, including, without limitation, any warranties or conditions
148+
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
149+
PARTICULAR PURPOSE. You are solely responsible for determining the
150+
appropriateness of using or redistributing the Work and assume any
151+
risks associated with Your exercise of permissions under this License.
152+
153+
8. Limitation of Liability. In no event and under no legal theory,
154+
whether in tort (including negligence), contract, or otherwise,
155+
unless required by applicable law (such as deliberate and grossly
156+
negligent acts) or agreed to in writing, shall any Contributor be
157+
liable to You for damages, including any direct, indirect, special,
158+
incidental, or consequential damages of any character arising as a
159+
result of this License or out of the use or inability to use the
160+
Work (including but not limited to damages for loss of goodwill,
161+
work stoppage, computer failure or malfunction, or any and all
162+
other commercial damages or losses), even if such Contributor
163+
has been advised of the possibility of such damages.
164+
165+
9. Accepting Warranty or Additional Liability. While redistributing
166+
the Work or Derivative Works thereof, You may choose to offer,
167+
and charge a fee for, acceptance of support, warranty, indemnity,
168+
or other liability obligations and/or rights consistent with this
169+
License. However, in accepting such obligations, You may act only
170+
on Your own behalf and on Your sole responsibility, not on behalf
171+
of any other Contributor, and only if You agree to indemnify,
172+
defend, and hold each Contributor harmless for any liability
173+
incurred by, or claims asserted against, such Contributor by reason
174+
of your accepting any such warranty or additional liability.
175+
176+
END OF TERMS AND CONDITIONS
177+
178+
APPENDIX: How to apply the Apache License to your work.
179+
180+
To apply the Apache License to your work, attach the following
181+
boilerplate notice, with the fields enclosed by brackets "{}"
182+
replaced with your own identifying information. (Don't include
183+
the brackets!) The text should be enclosed in the appropriate
184+
comment syntax for the file format. We also recommend that a
185+
file or class name and description of purpose be included on the
186+
same "printed page" as the copyright notice for easier
187+
identification within third-party archives.
188+
189+
Copyright (c) 2020. findinpath.com ([email protected])
190+
191+
Licensed under the Apache License, Version 2.0 (the "License");
192+
you may not use this file except in compliance with the License.
193+
You may obtain a copy of the License at
194+
195+
http://www.apache.org/licenses/LICENSE-2.0
196+
197+
Unless required by applicable law or agreed to in writing, software
198+
distributed under the License is distributed on an "AS IS" BASIS,
199+
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
200+
See the License for the specific language governing permissions and
201+
limitations under the License.

‎NOTICE

+13
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
The following libraries are included in packaged versions of this project:
2+
3+
* Confluent Kafka Connect JDBC
4+
* DISCLOSURE: Large parts of the codebase of this component are based on the source code
5+
* from https://github.com/confluentinc/kafka-connect-jdbc
6+
* COPYRIGHT: Copyright 2018-2020 Confluent Inc.
7+
* LICENSE: licenses/LICENSE.confluentcommunity.txt
8+
* HOMEPAGE: https://confluent.io/
9+
10+
* SLF4J
11+
* COPYRIGHT: Copyright (c) 2004-2013 QOS.ch
12+
* LICENSE: licenses/LICENSE.mit.txt
13+
* HOMEPAGE: http://www.slf4j.org/

‎README.md

+152
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,152 @@
1+
Kafka Connect Nested Set JDBC Sink Connector
2+
===========================================
3+
4+
This is a [Kafka Connector](http://kafka.apache.org/documentation.html#connect)
5+
for loading [nested set model](https://en.wikipedia.org/wiki/Nested_set_model) to any JDBC compatible database.
6+
7+
8+
The Confluent [kafka-connect-jdbc sink connector](https://docs.confluent.io/current/connect/kafka-connect-jdbc/sink-connector/index.html)
9+
was already developed to allow exporting of data from Apache Kafka topics to any relational database.
10+
11+
This connector builts on top of the existing `kakfa-connect-jdbc sink connector`
12+
functionality and provides a safeguard on the sink
13+
database side in order to avoid adding invalid updates to the nested set model.
14+
The sinked nested set records will be placed in an `INSERT only` log table
15+
and only when the nested set configuration is valid, the log records get
16+
inserted to the destination sink table.
17+
18+
19+
The project source code is a port of the Confluent's
20+
[kafka-connect-jdbc](https://github.com/confluentinc/kafka-connect-jdbc)
21+
adapted to consistently sink nested set data.
22+
This is why large portions of the `kafka-connect-jdbc` project code have
23+
been copied and adapted.
24+
25+
26+
## Nested set model
27+
28+
As stated on [Wikipedia](https://en.wikipedia.org/wiki/Nested_set_model)
29+
> The nested set model is a technique for representing nested sets (also known as trees or hierarchies) in relational databases.
30+
31+
Details about the advantages of the nested set model are very well
32+
described in the following article:
33+
34+
https://www.sitepoint.com/hierarchical-data-database/
35+
36+
![Nested Set Tree](images/nested-set.gif)
37+
38+
![Nested Set Model](images/nested-set-model.png)
39+
40+
41+
##Syncing nested set models over Apache Kafka
42+
43+
Bellow is described a concrete example to showcase the complexity associated
44+
with syncing a nested set model over Apache Kafka.
45+
46+
Let's take the following example of going from a nested set model
47+
consisting only of the root node:
48+
49+
```
50+
|1| A |2|
51+
```
52+
53+
to the nested set model (after adding two children) consisting of 3 nodes:
54+
55+
```
56+
|1| A |6|
57+
├── |2| B |3|
58+
└── |4| C |5|
59+
```
60+
61+
In the snippets above the tree node labels are prefixed by their `left` and `right`
62+
nested set model coordinates.
63+
64+
Via `kafka-connect-jdbc` the records corresponding to the tuple updates may come in various
65+
ordering:
66+
67+
```
68+
| label | left | right |
69+
|-------|------|-------|
70+
| A | 1 | 6 |
71+
| B | 2 | 3 |
72+
| C | 4 | 5 |
73+
```
74+
or
75+
```
76+
| label | left | right |
77+
|-------|------|-------|
78+
| B | 2 | 3 |
79+
| C | 4 | 5 |
80+
| A | 1 | 6 |
81+
```
82+
or, in case that there's a problem on the jdbc source connector's side
83+
```
84+
| label | left | right |
85+
|-------|------|-------|
86+
| B | 2 | 3 |
87+
| C | 4 | 5 |
88+
```
89+
90+
or any other combinations of the three tuples listed above because the records
91+
are polled in batches of different sizes from Apache Kafka.
92+
93+
94+
Going from the nested set model table content
95+
96+
```
97+
| label | left | right |
98+
|-------|------|-------|
99+
| A | 1 | 2 |
100+
```
101+
towards
102+
103+
```
104+
| label | left | right |
105+
|-------|------|-------|
106+
| A | 1 | 6 |
107+
```
108+
109+
or
110+
111+
```
112+
| label | left | right |
113+
|-------|------|-------|
114+
| A | 1 | 6 |
115+
| B | 2 | 3 |
116+
```
117+
118+
would intermittently render the nested set model corrupt until
119+
all the records from the source nested set model are synced over Apache Kafka.
120+
In the unlikely case that there's an outage during a tree update on the Kafka Connect JDBC
121+
source connector side, the nested set model from the sink database side would stay corrupt
122+
until the outage is fixed or until the nested set model would be manually adjusted.
123+
124+
125+
One solution to cope with this sync problem would be to separate
126+
the nested set model from what is synced over Apache Kafka.
127+
128+
![Sink database table diagram](images/sink-database-table-diagram.png)
129+
130+
131+
In the table diagram above, the `nested_set_node_log` table is an `INSERT only` table
132+
in which is written whenever a new record(s) is read from Apache Kafka.
133+
The `log_offset` table has only one tuple pointing to the last `nested_set_node_log` tuple id
134+
processed when updating the `nested_set_node` table.
135+
136+
Whenever new records are read from Apache Kafka, there will be a transactional attempt
137+
to apply all the updates from `nested_set_node_log` made after the saved entry in the `log_offset`
138+
table to the existing configuration of the `nested_set_node` nested set model.
139+
140+
If the applied updates lead to a valid nested set model configuration, then the `nested_set_node`
141+
table will be updated and the log offset will be set to the latest processed `nested_set_node_log` entry.
142+
Otherwise the `nested_set_node` table stays in its previous state.
143+
144+
## Contribute
145+
146+
Source code: https://github.com/findinpath/kafka-connect-nested-set-jdbc-sink
147+
148+
Issue Tracker: https://github.com/findinpath/kafka-connect-nested-set-jdbc-sink/issues
149+
150+
## License
151+
152+
This project is licensed under the [Apache License](LICENSE)

0 commit comments

Comments
 (0)