cindi 0.9.1.1

CINDI is a Meta-DBMS to support rapid application prototyping.

Cacheable Implementation Neutral Data Intermediate

CINDI is a Meta Database Management System which provides a simple way for front-end applications to perform CRUD operations with various back-end stores. CINDI is written in Python 3, and is available in the PyPI Index as a PIP package.

CINDI is intended to be used during the early rapid-prototyping / idea phase, so that developers may focus on the layout, functionality, and usability of a front-end application. Think of CINDI as a temporary substitute, until a proper back-end infrastructure is built. This way, the initial pioneers of a project need only to focus their energy on the front-end(s).

The idea is to forgo the traditional map of API endpoints usually provided by a back-end. Instead, front-end code will submit INDI statements directly to a single endpoint, and receive JSON responses accordingly. The result is, most application logic is shifted into the front-end code, which simplifies the rapid prototyping of applications.

Later, when a minimal-viable-product had been demonstrated to stakeholders, and more developers can be assigned to the project, CINDI would then be replaced with a traditional API back-end.

Users may configure CINDI to use one, some, or all of the currently supported storage systems:

• PostgreSQL
• MySQL
• SQLite3
• MongoDB
• Redis

An easy Implementation Neutral Data Intermediate language is provided in order to abstract-away the underlying chosen store(s). The INDI language is similar to SQL, but re-worded to enforce the CRUD mentality.

Brief INDI Language Tutorial

The INDI language uses four major CRUD keywords: CREATE, READ, UPDATE, and DELETE.

CINDI will cache READ operations in-memory, until it detects those result-sets are stale (due to another CREATE, UPDATE, or DELETE affecting the data).

In order to demonstrate the INDI language, consider the following SQLite3 schema:

 CREATE TABLE nonsense (
 	id INTEGER NOT NULL PRIMARY KEY,
	nonsense_a TEXT,
	nonsense_b TEXT,
	nonsense_c TEXT
	);

The above SQL statement would be prepared (manually, by the user) for CINDI before starting. Then, after loading CINDI, the four CRUD operations may be performed by submitting INDI statements to the system.

For example, here is an INDI CREATE statement:

CREATE IN nonsense FIELDS (nonsense_a, nonsense_b, nonsense_c) VALUES ("hekkin big", "skare", "today and now")

There would be no 'result' to the above query, other than the underlying store(s) being modified to reflect the insertion of new data. Client-side, this is what would be received as a response:

[[]]

Next example, here is an INDI READ statement:

READ IN nonsense id 1 FIELDS nonsense_a

The READ has a result, it would be a JSON array looking like this:

[[['hekkin big']]]

Now for a more comprehensive READ:

READ IN nonsense ALL RECORDS FIELDS (id, nonsense_a, nonsense_b, nonsense_c)

This retrieves all records from the nonsense table, including all columns:

[[[1, 'hekkin big', 'skare', 'today and now']]]

It appears that 'skare' is spelled wrong, so to UPDATE that:

UPDATE IN nonsense nonsense_b skare FIELDS (nonsense_b) VALUES (scare)

The literal result is an empty set:

[[]]

Check to see just that column had been updated:

READ IN nonsense id 1 FIELDS nonsense_b

Result:

[[['scare']]]

Finally, to DELETE the record:

DELETE IN nonsense id 1

A subsequent READ would return an empty set. Note the DELETE may have queried by any field, not just the 'id'!

VALUES quotes are optional, unless the string to be stored contains spaces.

See the doc/demo.txt file for the verbose output from the above demo.

The doc folder also contains schema examples for the other supported systems.

---

Why ?

The above demonstration may seem trivial, however, consider that CINDI will support managing these INDI statements even if the backing-store is a NoSQL solution, such as MongoDB or Redis. The results are consistent, and if multiple stores are enabled, then any cache-missed READ will query all the stores, and compare the results to ensure consistency across the storage mechanisms.

If clients are submitting the same INDI queries repetitively, then the result from the first time is served from an in-memory Python dictionary. That cached query is discarded when an affecting CREATE, UPDATE, or DELETE occurs.

In the case of the NoSQL solutions, CINDI manages the concept of tables, columns, and primary keys. In particular, the MongoDB setup requires only creating a database, and the Redis setup requires nothing!

CINDI will not automatically initialize SQL / Mongo schemas, this must be done manually prior to runtime. That is why the author has provided a couple Docker demos, read on!

Check cindi_tests.py for more INDI language examples.

Installation, Easiest: cindi-lite Docker Compose Pack

Please go here and follow the instructions in order to have Docker Compose orchestrate the setup of ultasun/cindi-lite, which will consume the least resources. Along the way, you'll learn everything there is to know about configuring the CINDI runtime for a minimalist SQLite3-only backing-store.

Installation, Easier: cindi-plus Docker Compose Pack

Please go here and follow the instructions in order to have Docker Compose orchestrate the complete setup and demonstration of ultasun/cindi, which will, by default, consume significantly more resources than ultasun/cindi-lite. Along the way, you'll learn everything there is to know about configuring the CINDI runtime for a full installation with all five supported backing-stores running simultaneously

Installation, Easy: cindi-lite Docker image (no orchestration)

A Docker image ultasun/cindi-lite is available on Docker Hub, it will use a SQLite3 setup, and provide a similar experience to Installing & Basic Setup on SQLite3.

After start-up, development Flask server will not have SSL enabled.

0. Install the latest version of Docker on your system.
1. Open a terminal, and run the following command for a disposable demo:
   • $ docker run -dp 36963:36963 --rm ultasun/cindi-lite
   • Or, if you'd like to persist logs and data with named-mounts:
   • $ docker run -dp 36963:36963 -v cindi-lite-data:/app/data -v cindi-lite-logs:/app/logs ultasun/cindi-lite
   • Feel free to use bind-mounts for easier access to the produced data.
2. Use Docker Desktop to open a terminal into the running container, or otherwise docker exec -it into the container, and initialize the EXAMPLE data:
   • $ python
   • >>> import cindi
   • >>> cindi.quick_unit_tests()
   • Verify the return value is True, which means all 17 tests passed!
3. Use Postman (or something) to POST some INDI statements to http://localhost:36963/evaluate, such as:
   • READ IN nonsense ALL RECORDS FIELDS (id, nonsense_a, nonsense_b, nonsense_c)
   • Back in the python console, the full list of EXAMPLES may be viewed:
   • >>> cindi.print_2d_list(cindi.EXAMPLE_LIST)
     • These are the EXAMPLES which were ran during cindi.quick_unit_tests()
       • There is no harm in running the DDL or DML statements again!

Hard: Manual Installation & Basic Setup on SQLite3

Installing without Docker

Docker is not necessary to utilize CINDI. This installation demo will show manual installation from PyPI, and configuration using only SQLite3, to keep it brief. Please follow the detailed tutorial on cindi-plus to learn about configuring other backing-store systems.

1. pip install cindi
2. In your current working directory, create a folder called config:
   • $ mkdir config
3. In the config folder, create empty stores.txt and tables.txt files.
   • $ cd config && touch stores.txt && touch tables.txt && cd ..
4. Open stores.txt with a text editor -- the file must contain a python dictionary, here is the basic example using only SQLite3:
   • {'sqlite3': {'db': 'db0', 'sqlite3_file_prefix': ''}}
5. Open tables.txt with a text editor -- the file must contain a python list (or tuple), here is the basic example:
   • ['nonsense']
6. To open the SQLite3 database for intialization, in your terminal, run:
   • $ sqlite3 db0.db
   • You may need to install SQLite3 if the command is not found.
7. In the SQLite3 console, initialize the schema:
   • sqlite> CREATE TABLE nonsense (id INTEGER NOT NULL PRIMARY KEY, nonsense_a TEXT, nonsense_b TEXT, nonsense_c TEXT);
   • Save and quit: sqlite> .quit
8. In your terminal, run:
   • $ python3
9. Finally, try it out! Populate the store(s) with EXAMPLE data:
   • >>> import cindi
   • >>> cindi.quick_unit_tests()
     • The above function returns True if all tests succeed.
   • >>> cindi.quick_cindi(cindi.EXAMPLE5)
     • The above function returns a multi-dimensional list of values.

Credits

Please read the LICENSE. This is alpha-quality software, you are likely to find bugs! Please submit feedback! Thank you for evaluating CINDI!