fix ext readme

extensions/pgx_pgmq/README.md

@@ -2,7 +2,6 @@
 
 A lightweight distributed message queue. Like [AWS SQS](https://aws.amazon.com/sqs/) and [RSMQ](https://github.com/smrchy/rsmq) but on Postgres.
 
-
 ## Features
 
 - Lightweight - Rust and Postgres only
@@ -12,23 +11,21 @@ A lightweight distributed message queue. Like [AWS SQS](https://aws.amazon.com/s
 - Messages can be archived, instead of deleted, for long-term retention and replayability
 - Completely asynchronous API
 
-- [Postgres Message Queue](#postgres-message-queue)
-  - [Installation](#installation)
+## Table of Contents
+- [Postgres Message Queue (PGMQ)](#postgres-message-queue-pgmq)
+  - [Features](#features)
+  - [Table of Contents](#table-of-contents)
+  - [Start CoreDB Postgres](#start-coredb-postgres)
   - [Python Examples](#python-examples)
-    - [Connect to postgres](#connect-to-postgres)
-    - [Create and list queues](#create-and-list-queues)
-    - [Send a message to the queue](#send-a-message-to-the-queue)
-    - [Read a message from the queue](#read-a-message-from-the-queue)
-    - [Delete a message from the queue](#delete-a-message-from-the-queue)
   - [SQL Examples](#sql-examples)
     - [Creating a queue](#creating-a-queue)
-    - [Send a message](#send-a-message)
-    - [Read a message](#read-a-message)
+    - [Send two message](#send-two-message)
+    - [Read messages](#read-messages)
     - [Pop a message](#pop-a-message)
     - [Archive a message](#archive-a-message)
     - [Delete a message](#delete-a-message)
-  - [Development](#development)
-  - [Packaging](#packaging)
+- [Development](#development)
+- [Packaging](#packaging)
 
 ## Start CoreDB Postgres
 
@@ -41,131 +38,43 @@ docker run -d --name postgres -e POSTGRES_PASSWORD=postgres -p 5432:5432 quay.io
 
 ## Python Examples
 
-### Connect to postgres
-
-```python
-import json
-import pprint
-
-from sqlalchemy import create_engine, text
-
-engine = create_engine("postgresql://postgres:postrgres@0.0.0.0:5432/postgres")
-```
-
-### Create and list queues
-
-```python
-with engine.connect() as con:
-    # create a queue
-    created = con.execute(text( "select * from pgmq_create('myqueue');"))
-    # list queues
-    list_queues = con.execute(text( "select * from pgmq_list_queues()"))
-    column_names = list_queues.keys()
-    rows = list_queues.fetchall()
-    print("### Queues ###")
-    for row in rows:
-        pprint.pprint(dict(zip(column_names, row)))
-```
-
-```python
-'### Queues ###'
-{
-  'created_at': datetime.datetime(2023, 2, 7, 2, 5, 39, 946356,
-  tzinfo=datetime.timezone(datetime.timedelta(days=-1, seconds=64800))),
- 'queue_name': 'myqueue'
-}
- ```
-
-
-### Send a message to the queue
-
-```python
-with engine.connect() as con:
-    # send a message
-    msg = json.dumps({"yolo": 42})
-    msg_id = con.execute(text(f"select * from pgmq_send('x', '{msg}') as msg_id;"))
-    column_names = msg_id.keys()
-    rows = msg_id.fetchall()
-    print("### Message ID ###")
-    for row in rows:
-        pprint.pprint(dict(zip(column_names, row)))
-```
-
-```python
-'### Message ID ###'
-{'msg_id': 1}
-```
-
-### Read a message from the queue
-
-```python
-with engine.connect() as con:
-    # read a message, make it unavailable to be read again for 5 seconds
-    read = con.execute(text("select * from pgmq_read('x', 5);"))
-    column_names = read.keys()
-    rows = read.fetchall()
-    print("### Read Message ###")
-    for row in rows:
-        pprint.pprint(dict(zip(column_names, row)))
-```
-
-```python
-'### Read Message ###'
-{
-  'enqueued_at': datetime.datetime(2023, 2, 7, 2, 51, 50, 468837, tzinfo=datetime.timezone(datetime.timedelta(days=-1, seconds=64800))),
-  'message': {'myqueue': 42},
- 'msg_id': 1,
- 'read_ct': 1,
- 'vt': datetime.datetime(2023, 2, 7, 16, 9, 4, 826669, tzinfo=datetime.timezone(datetime.timedelta(days=-1, seconds=64800)))
-}
- ```
 
-### Delete a message from the queue
-
-```python
-with engine.connect() as con:
-    # delete a message
-    deleted = con.execute(text("select pgmq_delete('x', 1);"))
-    column_names = deleted.keys()
-    rows = deleted.fetchall()
-    print("### Message Deleted ###")
-    for row in rows:
-        pprint.pprint(dict(zip(column_names, row)))
-```
-```
-'### Message Deleted ###'
-{'pgmq_delete': True}
-```
+See python examples in [examples/python.py](examples/python.py)
 
 ## SQL Examples
 
+
 ```bash
+# Connect to Postgres
 psql postgres://postgres:postgres@0.0.0.0:5432/postgres
 ```
 
 ```sql
+-- create the extension
 CREATE EXTENSION pgmq;
 ```
 
 ### Creating a queue
 
 ```sql
+-- creates the queue.
 SELECT pgmq_create('my_queue');
 
  pgmq_create
 -------------
-
 ```
 
 ### Send two message
 
 ```sql
+-- messages are sent as JSON
 pgmq=# 
-SELECT * from pgmq_send('my_queue', '{"foo": "bar"}');
-SELECT * from pgmq_send('my_queue', '{"foo": "bar"}');
+SELECT * from pgmq_send('my_queue', '{"foo": "bar1"}');
+SELECT * from pgmq_send('my_queue', '{"foo": "bar2"}');
 ```
 
-```
+```sql
+-- the message id is returned from the send function
  pgmq_send 
 -----------
          1
@@ -182,7 +91,8 @@ SELECT * from pgmq_send('my_queue', '{"foo": "bar"}');
 Read two message from the queue. Make them invisible for 30 seconds.
 
 ```sql
-pgmq=# SELECT * from pgmq_read('my_queue', 30, 1);
+-- parameters are queue name, visibility timeout, and number of messages to read
+pgmq=# SELECT * from pgmq_read('my_queue', 30, 2);
 
  msg_id | read_ct |              vt               |          enqueued_at          |    message
 --------+---------+-------------------------------+-------------------------------+---------------
@@ -196,14 +106,13 @@ If the queue is empty, or if all messages are currently invisible, no rows will
 pgx_pgmq=# SELECT * from pgmq_read('my_queue', 30, 1);
  msg_id | read_ct | vt | enqueued_at | message
 --------+---------+----+-------------+---------
-
 ```
 
 ### Pop a message
 
-Read a message and immediately delete it from the queue. Returns `None` if the queue is empty.
 
 ```sql
+-- Read a message and immediately delete it from the queue. Returns `None` if the queue is empty.
 pgmq=# SELECT * from pgmq_pop('my_queue');
 
  msg_id | read_ct |              vt               |          enqueued_at          |    message
@@ -213,23 +122,24 @@ pgmq=# SELECT * from pgmq_pop('my_queue');
 
 ### Archive a message
 
-Archiving a message removes it from the queue, and inserts it to the archive table.
-TODO:
 
+```sql
+-- Archiving a message removes it from the queue, and inserts it to the archive table.
+-- TODO: implement this in the extension
+
+```
 
 ### Delete a message
-Delete a message with id `1` from queue named `my_queue`.
+
 ```sql
+-- Delete a message id `1` from queue named `my_queue`.
 pgmq=# select pgmq_delete('my_queue', 1);
  pgmq_delete
 -------------
  t
  ```
 
-
-
-
-## Development
+# Development
 
 Setup `pgx`.
 
@@ -251,7 +161,7 @@ Run the dev environment
 cargo pgx run pg14
 ```
 
-## Packaging
+# Packaging
 
 Run this script to package into a `.deb` file, which can be installed on Ubuntu.