Added a simple implementation of the polling outbox pattern

[demos/kafka/outbox] / README.md

diff --git a/README.md b/README.md
index 2748ed9..2c61a4e 100644 (file)
--- a/README.md
+++ b/README.md
@@ -9,25 +9,25 @@ Execute [README.sh](README.sh) in a shell to demonstrate the example:
 
 The script will...
 
-* compile the component,
-* package it as Docker-Images,
-* start up the component and a PostreSQL as containers in a [Compose-Setup](docker-compose.yml),
+* compile the two components,
+* package them as Docker-Images,
+* start up the components and a minimal Kafka Cluster as containers in a [Compose-Setup](docker-compose.yml),
 * execute example-queries (CREATE / DELETE) against the API of [the example-project](https://juplo.de/implementing-the-outbox-pattern-with-kafka-part-0-the-example/) and
-* tail the logs of the containers `jdbc` to show what is going on.
+* tail the logs of the containers `jdbc` and `kafkacat` to show what is going on.
 
 You can verify the expected outcome of the demonstration by running a command like the following:
 
-    $ docker-compose exec postgres psql -Uoutbox -c'SELECT * FROM outbox;' -Ppager=0  outbox | grep peter
-      1 | peter1  | "CREATED" | 2021-05-16 13:20:36.849
-     10 | peter2  | "CREATED" | 2021-05-16 13:20:42.141
-     19 | peter3  | "CREATED" | 2021-05-16 13:20:47.136
-     28 | peter4  | "CREATED" | 2021-05-16 13:20:52.087
-     37 | peter5  | "CREATED" | 2021-05-16 13:20:57.512
-     46 | peter6  | "CREATED" | 2021-05-16 13:21:02.493
-     55 | peter7  | "CREATED" | 2021-05-16 13:21:07.503
+    $ docker-compose logs kafkacat | grep peter
+    kafkacat_1   | peter1:"CREATED"
+    kafkacat_1   | peter2:"CREATED"
+    kafkacat_1   | peter3:"CREATED"
+    kafkacat_1   | peter4:"CREATED"
+    kafkacat_1   | peter5:"CREATED"
+    kafkacat_1   | peter6:"CREATED"
+    kafkacat_1   | peter7:"CREATED"
     $
 
-The example-output shows, that the CREATE-event for users with "peter" in their username are only stored exactly once in the outbox-table, although the script issues several requests for each of these users.
+The example-output shows, that the CREATE-event for users with "peter" in their username are only issued exactly once, although the script issues several requests for each of these users.
 
 Be aware, that the outcome of the script will be different, if you run it several times.
 In order to reproduce the same behaviour, you have to shut down the Compose-Setup before rerunning the script: