mongoose-multi
Version:
Create multiple Mongoose connections to severals DBs; supports also gridfs
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# mongoose-multi
Create multiple Mongoose connections to severals DBs.
Note: gridfs support was removed in 1.0.0
## Installation
```
npm install mongoose-multi --save
```
## Getting started
### Use the module in your code
The syntax is 'database.collection' for maximum clarity.
```javascript
db.application.customer.find().exec(function(err, docs) {
// do sth. here with customers
});
```
"customer" is the mongoose model and can use it's methods. See <http://mongoosejs.com/docs/guide.html>.
### Start the Module
Idea:
- network configuration in separate file (different modes for production, development, etc.)
- schemas in separate file
```javascript
// Start the module in the application
var dbConfig = require('./config.js').db, // external network file
mongooseMulti = require('mongoose-multi'),
db = mongooseMulti.start(dbConfig, node.env.PWD + './schemas.js'); // schema file path => mongoose-multi trys to require it
// wait for connection to be open
db.application.mongooseConnection.once('open', function () {
// use it
db.application.customer.find().exec(function(err, docs) {
// do sth. here with customers
});
db.books.article.findOneAndUpdate().exec(function(err, doc) {
// do sth. here with article
});
db.application.customer.findExactOne({}, function(err, doc) {
// err if no or more than one docs are found
// do sth. here with customer
});
db.books.article.findMinOne({}, function(err, doc) {
// err if no docs are found
// do sth. here with article
});
});
```
#### Network config file
You might integrate this your way in your config. mongoose-multi needs one object with all database urls to connect to.
```javascript
module.exports = {
"db":{
"application": 'mongodb://localhost:27017/application',
"book": 'mongodb://localhost:27017/books'
}
};
```
#### Mongoose Schemas file
```javascript
// mongose is needed here for the definition
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
module.exports = {
application:{ // database
customer: new Schema({ // collection
mailaddress: {type: String},
}),
settings: new Schema({ // collection
customerId: {type: String, required: false},
options: {type: Array, required: false},
}),
},
book:{ // database
article: new Schema({ // collection
description: {type: String},
numOfPages: {type:Number, required: false},
weight:{type:Number, required: false},
}),
paperback: new Schema({ // collection
description: {type: String, required: false},
numOfPages: {type:Number, required: false},
weight:{type:Number, required: false},
})
}
};
```
#### Advanced Schema file options
Option 1: If you need to modifie the schemas in your code, you can do so and then directly pass the object for all schemas.
```javascript
// Start the module
var dbConfig = require('./config.js'), // external network file
schemaFile = require('./schemas.js'), // external schema file
mongooseMulti = require('mongoose-multi'),
db = mongooseMulti.start(dbConfig, schemaFile);
// use "db" in your app ..
```
Option 2: For bigger projects you can have a schema file folder. Each database has one file with it's name.
```javascript
// Start the module
var dbConfig = require('./config.js').db, // external network file
mongooseMulti = require('mongoose-multi'),
db = mongooseMulti.start(dbConfig, node.env.PWD + './schemas'); // try to require all schema files within folder
// use "db" in your app ..
```
`./schemas/application` looks like:
```javascript
/** schemas for db application
* @version 0.0.2
*/
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
module.exports = {
customer: new Schema({ // collection
mailaddress: {type: String},
}),
settings: new Schema({ // collection
customerId: {type: String, required: false},
options: {type: Array, required: false},
}),
};
```
`./schemas/book` looks like:
```javascript
/** schemas for db book
* @version 0.0.4
*/
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
module.exports = {
article: new Schema({ // collection
description: {type: String},
numOfPages: {type:Number, required: false},
weight:{type:Number, required: false},
}),
paperback: new Schema({ // collection
description: {type: String, required: false},
numOfPages: {type:Number, required: false},
weight:{type:Number, required: false},
})
};
```
#### Network config file
The network file may include all urls to your databases:
```javascript
module.exports = {
"db":{
"application": 'mongodb://localhost:27017/application',
"book": 'mongodb://localhost:27017/books'
}
};
```
Alternative you can also pass options:
```javascript
module.exports = {
module.exports = {
db: {
online: {
url: "mongodb://localhost:27017/auditoria",
options : {useNewUrlParser: true}
},
history: {
url: "mongodb://otheHost:27017/db_arquitectura",
options : {}
}
}
}
};
```
## Reuse the mongoose connection
The original mongoose connection is also returned for every DB to use it in other own modules, or especially the events like:
```javascript
// we assume a database "application"
db.application.mongooseConnection.once('open', function() {
console('db application now open');
startSomething(db); // start after db is ready
});
```
## Mongoose reconnection issues
There have been several issues, that prevent a correct reconnect to the databse.
In many cases, one might never see a disconntect, but a app in production should reconnect reliable.
In this version we simple terminate the process after 10 seconds disconnect and restart it automatic with pm2.
This might be changed in the future, when there is a better and reliable workaround.
Check if this is for your process.
## Development
Install the dev tools with
> npm install
Then you can runs some test cases and eslint with:
> npm test
## ToDo
- tests