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https://github.com/nikunjy/rules
Generic Rules engine in golang
https://github.com/nikunjy/rules
antlr golang json-query json-rules jsonquery rules rules-engine
Last synced: 2 days ago
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Generic Rules engine in golang
- Host: GitHub
- URL: https://github.com/nikunjy/rules
- Owner: nikunjy
- License: mit
- Created: 2019-04-17T06:03:29.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-02-24T12:13:47.000Z (9 months ago)
- Last Synced: 2024-08-02T20:47:52.084Z (3 months ago)
- Topics: antlr, golang, json-query, json-rules, jsonquery, rules, rules-engine
- Language: Go
- Homepage:
- Size: 305 KB
- Stars: 213
- Watchers: 7
- Forks: 44
- Open Issues: 8
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- my-awesome - nikunjy/rules - query,json-rules,jsonquery,rules,rules-engine pushed_at:2024-02 star:0.2k fork:0.0k Generic Rules engine in golang (Go)
README
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[](https://pkg.go.dev/github.com/nikunjy/rules)
[](https://github.com/nikunjy/rules/releases/latest)
[](https://github.com/nikunjy/rules/releases/latest)
[](https://github.com/nikunjy/rules/commits)
[](https://opensource.org/licenses/MIT)
[](https://github.com/nikunjy/rules/stargazers/)
# Golang Rules Engine
Rules engine written in golang with the help of antlr.
This package will be very helpful in situations where you have a generic rule and want to verify if your values (specified using `map[string]interface{}`) satisfy the rule.
Here are some examples:
```
parser.Evaluate("x eq 1", map[string]interface{}{"x": 1})
parser.Evaluate("x == 1", map[string]interface{}{"x": 1})
parser.Evaluate("x lt 1", map[string]interface{}{"x": 1})
parser.Evaluate("x < 1", map[string]interface{}{"x": 1})
parser.Evaluate("x gt 1", map[string]interface{}{"x": 1})
parser.Evaluate("x.a == 1 and x.b.c <= 2", map[string]interface{}{
"x": map[string]interface{}{
"a": 1,
"b": map[string]interface{}{
"c": 2,
},
},
})
parser.Evaluate("y == 4 and (x > 1)", map[string]interface{}{"x": 1})
parser.Evaluate("y == 4 and (x IN [1,2,3])", map[string]interface{}{"x": 1})
parser.Evaluate("y == 4 and (x eq 1.2.3)", map[string]interface{}{"x": "1.2.3"})
```
## Operations
All the operations can be written capitalized or lowercase (ex: `eq` or `EQ` can be used)
Logical Operations supported are `and` `or`
Compare Expression and their definitions
| expression | meaning |
-------------|------------
| eq | equals to |
| == | equals to |
| ne | not equal to |
| != | not equal to |
| lt | less than |
| < | less than |
| gt | greater than |
| > | greater than |
| le | less than or equal to |
| <= | less than or equal to |
| ge | greater than or equal to|
| >= | greater than or equal to|
| co | contains |
| sw | starts with |
| ew | ends with |
| in | in a list |
| pr | present, will be true if you have a key as true |
| not | not of a logical expression |
## How to use it
Use your dependency manager to import `github.com/nikunjy/rules/parser`. This will let you parse a rule and keep the parsed representation around.
Alternatively, you can also use `github.com/nikunjy/rules` directly to call the root `Evaluate(string, map[string]interface{})` method.
I would recommend importing `github.com/nikunjy/rules/parser`
## How to extend the grammar
1. Please look at this [antlr tutorial](https://tomassetti.me/antlr-mega-tutorial/#setup-antlr), the link will show you how to setup antlr.
The article has a whole lot of detail about antlr I encourage you to read it, you might also like [my blog post](https://medium.com/@nikunjyadav/generic-rules-engine-in-golang-using-antlr-d30a0d0bb565) about this repo.
2. After taking a look at the antlr tutorial, you can extend the [JsonQuery.g4 file](https://github.com/nikunjy/rules/blob/master/parser/JsonQuery.g4).
3. Compile the parser `antlr4 -Dlanguage=Go -visitor -no-listener JsonQuery.g4 -o ./` (Note: `-o` is the output directory, make sure all the stuff it generates is in the `parser` directory of the root repo folder)
[ci-img]: https://api.travis-ci.org/nikunjy/rules.svg?branch=master
[ci]: https://travis-ci.org/nikunjy/rules