PLV8ify

Introduction

plv8ify uses esbuild to bundle an input typescript file and writes multiple SQL files (one for each exported function in the typescript file) containing Postgres functions using PLV8.

Why

• Interchange code between API and Database
• Write code in Typescript and use it in Postgres

Example

1. npm install -g plv8ify
2. Sample input.ts

const { point: turfPoint } = require("@turf/helpers");

export function point(lat, long) {
  const pt = turfPoint([lat, long]);
  return pt;
}

3. Run plv8ify generate
4. Step 3 emits SQL file with names like ./plv8-dist/plv8ify_point.plv8.sql (one for each exported function)
5. Execute the generated ./plv8-dist/plv8ify_point.plv8.sql using a Postgres client
6. Call the generated function using a Postgres client SELECT plv8ify_point(52.5200,13.4050);
7. Steps 1-6 converted a Typescript file into a PLV8 executable function

CLI Arguments

Generate Command Flags	Type	Description	Default
--debug	Boolean	Print additional debug information	false
--write-esbuild-output	Boolean	Write the intermediate bundled Javascript output from ESBuild	false
--input-file	String	Specify an input file path (only Typescript supported at the moment)	input.ts
--output-folder	String	Specify an output folder	plv8ify-dist
--scope-prefix	String	Specify a scope prefix, by default plv8ify adds plv8ify_ as prefix for exported typescript functions	plv8ify
--fallback-type	String	Specify a fallback type when plv8ify fails to map a detected Typescript type to a Postges type	JSONB
--mode	'inline' or 'start_proc'	Bundle the library inline in each function or bundle the libary to be used with plv8.start_proc	inline

TODO

• README
• Custom function name
• Export multiple functions
• Input arguments - basic setup
• Flag to Emit intermediate file
• Input arguments - support most data types
• Input file name
• Output folder name
• Return type guessing
• Typescript as input
• Javascript as input
• Typescript for plv8ify code
• For each exported bundle, use tree-shaken bundle, currently, each bundle gets all of the Javascript
• Test cases

Caveats

• Very early, only a small number of types supported
• Only supports typescript as input at the moment
• Scaling an application server is easier than scaling a database server, moving the logic in database as postgres functions makes it easier (IMO SQL is declarative, like React for data) to call the code/do some things but you are effectively shifting compute from application server to database server which might be a bad idea in most cases.

Prior Art

• https://github.com/CSTARS/es6-to-plv8
• https://github.com/clkao/plv8x

Contact

If you want to reach out to me, please DM me on https://twitter.com/divyenduz or email me at mail at divyendusingh.com