CacheControl / CacheControl/json-rules-engine

Rule chaining not working with Promise.all

Open
#303 1 comment 0 reactions 0 assignees View on GitHub
Dominant language
JavaScript
Stars
3.1k
Forks
507
PR merge metrics
No merged PRs in 30d

Description

If I run the engine sequentially, I am getting the desired result. If I run it in parallel, I am getting results only for the first run.

**student-fav-subject.js**

```
const { Engine } = require("json-rules-engine");

const apiClient = require("./student-api-client");

let engine = new Engine();

async function start() {
let mathematicsSubjectRule = {
conditions: {
all: [
{
fact: "student-information",
operator: "contains",
value: "Mathematics",
path: "$.subjects",
},
],
},
event: { type: "studies-mathematics" },
priority: 10,
onSuccess: async function (event, almanac) {
almanac.addRuntimeFact("studiesMathematics", true);
},
onFailure: function (event, almanac) {
almanac.addRuntimeFact("studiesMathematics", false);
},
};
engine.addRule(mathematicsSubjectRule);

let physicsFavoriteRule = {
conditions: {
all: [
{
fact: "studiesMathematics",
operator: "equal",
value: true,
},
{
fact: "student-information",
operator: "equal",
value: "Physics",
path: "$.favoriteSubject",
},
],
},
event: {
type: "physics-favorite-subject",
params: {
message: " has Physics as their favorite subject",
},
},
};

engine.addRule(physicsFavoriteRule);

engine.addFact("student-information", function (params, almanac) {
console.log("loading student information...");
return almanac.factValue("studentName").then((studentName) => {
return apiClient.getStudentInformation(studentName);
});
});

engine.on("success", (event, almanac, ruleResult) => {
almanac.factValue("studentName").then((studentName) => {
switch (event.type) {
case "physics-favorite-subject":
console.log(
studentName,
"HAS".green,
"Physics as their favorite subject"
);
}
});
});

engine.on("failure", (event, almanac, ruleResult) => {
almanac.factValue("studentName").then((studentName) => {
switch (event.type) {
case "physics-favorite-subject":
const studiesMathResult = ruleResult.conditions.all.find(
(condition) => condition.fact === "studiesMathematics"
);
if (studiesMathResult) {
if (studiesMathResult.result) {
console.log(
studentName,
"DOES NOT".red,
"have Physics as favorite subject"
);
} else {
console.log(
studentName,
"CANNOT NOT".red,
"have Physics as favorite subject as they do not study Mathematics"
);
}
}
}
});
});

Promise.all([
engine.run({ studentName: "samuel" }),
engine.run({ studentName: "joseph" }),
engine.run({ studentName: "anthony" }),
]);

// await engine.run({ studentName: "samuel" });
// await engine.run({ studentName: "joseph" });
// await engine.run({ studentName: "anthony" });
}

start();

```

**student-api-client.js**

```
"use strict";

require("colors");
const fs = require("fs");

let studentData = require("./student-data.json");

/**
* mock api client for retrieving student information
*/
module.exports = {
getStudentInformation: (studentName) => {
const message = 'loading student information for "' + studentName + '"';
console.log(message.dim);
return new Promise((resolve, reject) => {
setImmediate(() => {
resolve(studentData[studentName]);
});
});
},
};

```

**student-data.json**

```
{
"john": {
"favoriteSubject": "Mathematics",
"subjects": ["Physics", "Mathematics"]
},
"anthony": {
"favoriteSubject": "Physics",
"subjects": ["Physics", "Mathematics"]
},
"george": {
"favoriteSubject": "History",
"subjects": ["History", "Mathematics"]
},
"samuel": {
"favoriteSubject": "Physics",
"subjects": ["Physics", "History", "Geography", "Chemistry"]
},
"joseph": {
"favoriteSubject": "Economics",
"subjects": ["Economics", "Mathematics", "History"]
}
}
```

## Output

### Running sequentially

```
loading student information...
loading student information for "samuel"
samuel CANNOT NOT have Physics as favorite subject as they do not study Mathematics
loading student information...
loading student information for "joseph"
joseph DOES NOT have Physics as favorite subject
loading student information...
loading student information for "anthony"
anthony HAS Physics as their favorite subject
```

### Running parallelly (Promise.all)

```
loading student information...
loading student information...
loading student information...
loading student information for "samuel"
loading student information for "joseph"
loading student information for "anthony"
samuel CANNOT NOT have Physics as favorite subject as they do not study Mathematics
```

Contributor guide

No contributing guide indexed for this repository

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.