Reusing Database Connections With Azure Functions Using Javascript












0















I cannot find clear information on how to manage database connections (MongoDB in my case) from an Azure function written in Javascript.



The Microsoft document below says to not create a connection for each invocation of the function by using static variables in C# using .NET Framework Data Provider for SQL Server and the pooling is handled by the client connection. It does not describe how to do this in Javascript.



https://docs.microsoft.com/en-us/azure/azure-functions/manage-connections



A solution of creating a global variable to hold the database client between invocations is described here but the author is not confident this is the correct way to do it.



http://thecodebarbarian.com/getting-started-with-azure-functions-and-mongodb.html



Has anyone used this in production or understand if this is the correct approach?










share|improve this question























  • Refer to MongoClient Connection Pooling section here and use similar pattern in your Azure Function. mongodb.github.io/node-mongodb-native/driver-articles/…

    – Baskar
    Nov 22 '18 at 4:37
















0















I cannot find clear information on how to manage database connections (MongoDB in my case) from an Azure function written in Javascript.



The Microsoft document below says to not create a connection for each invocation of the function by using static variables in C# using .NET Framework Data Provider for SQL Server and the pooling is handled by the client connection. It does not describe how to do this in Javascript.



https://docs.microsoft.com/en-us/azure/azure-functions/manage-connections



A solution of creating a global variable to hold the database client between invocations is described here but the author is not confident this is the correct way to do it.



http://thecodebarbarian.com/getting-started-with-azure-functions-and-mongodb.html



Has anyone used this in production or understand if this is the correct approach?










share|improve this question























  • Refer to MongoClient Connection Pooling section here and use similar pattern in your Azure Function. mongodb.github.io/node-mongodb-native/driver-articles/…

    – Baskar
    Nov 22 '18 at 4:37














0












0








0








I cannot find clear information on how to manage database connections (MongoDB in my case) from an Azure function written in Javascript.



The Microsoft document below says to not create a connection for each invocation of the function by using static variables in C# using .NET Framework Data Provider for SQL Server and the pooling is handled by the client connection. It does not describe how to do this in Javascript.



https://docs.microsoft.com/en-us/azure/azure-functions/manage-connections



A solution of creating a global variable to hold the database client between invocations is described here but the author is not confident this is the correct way to do it.



http://thecodebarbarian.com/getting-started-with-azure-functions-and-mongodb.html



Has anyone used this in production or understand if this is the correct approach?










share|improve this question














I cannot find clear information on how to manage database connections (MongoDB in my case) from an Azure function written in Javascript.



The Microsoft document below says to not create a connection for each invocation of the function by using static variables in C# using .NET Framework Data Provider for SQL Server and the pooling is handled by the client connection. It does not describe how to do this in Javascript.



https://docs.microsoft.com/en-us/azure/azure-functions/manage-connections



A solution of creating a global variable to hold the database client between invocations is described here but the author is not confident this is the correct way to do it.



http://thecodebarbarian.com/getting-started-with-azure-functions-and-mongodb.html



Has anyone used this in production or understand if this is the correct approach?







javascript mongodb mongoose azure-functions






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 22 '18 at 0:21









Hamish AndersonHamish Anderson

31




31













  • Refer to MongoClient Connection Pooling section here and use similar pattern in your Azure Function. mongodb.github.io/node-mongodb-native/driver-articles/…

    – Baskar
    Nov 22 '18 at 4:37



















  • Refer to MongoClient Connection Pooling section here and use similar pattern in your Azure Function. mongodb.github.io/node-mongodb-native/driver-articles/…

    – Baskar
    Nov 22 '18 at 4:37

















Refer to MongoClient Connection Pooling section here and use similar pattern in your Azure Function. mongodb.github.io/node-mongodb-native/driver-articles/…

– Baskar
Nov 22 '18 at 4:37





Refer to MongoClient Connection Pooling section here and use similar pattern in your Azure Function. mongodb.github.io/node-mongodb-native/driver-articles/…

– Baskar
Nov 22 '18 at 4:37












1 Answer
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Yes, there's a very close equivalence between C#/SQL storing a single SqlConnection instance in a static variable and JS/MongoDB storing a single Db instance in a global variable. The basic pattern for JS/MongoDB in Azure Functions is (assuming you're up to date for async/await - alternatively you can use callbacks as per your linked article):



// getDb.js

let dbInstance;

module.exports = async function() {
if (!dbInstance) {
dbInstance = await MongoClient.connect(uri);
}
return dbInstance;
};

// function.js

const getDb = require('./getDb.js');

module.exports = async function(context, trigger) {
let db = await getDb();
// ... do stuff with db ..
};


This will mean you only instantiate one Db object per host instance. Note this isn't one per Function App - if you're using a dedicated App Service Plan then there will be the number of instances you've specified in the plan, and if you're using a Consumption Plan then it'll vary depending on how busy your app is.






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    Yes, there's a very close equivalence between C#/SQL storing a single SqlConnection instance in a static variable and JS/MongoDB storing a single Db instance in a global variable. The basic pattern for JS/MongoDB in Azure Functions is (assuming you're up to date for async/await - alternatively you can use callbacks as per your linked article):



    // getDb.js

    let dbInstance;

    module.exports = async function() {
    if (!dbInstance) {
    dbInstance = await MongoClient.connect(uri);
    }
    return dbInstance;
    };

    // function.js

    const getDb = require('./getDb.js');

    module.exports = async function(context, trigger) {
    let db = await getDb();
    // ... do stuff with db ..
    };


    This will mean you only instantiate one Db object per host instance. Note this isn't one per Function App - if you're using a dedicated App Service Plan then there will be the number of instances you've specified in the plan, and if you're using a Consumption Plan then it'll vary depending on how busy your app is.






    share|improve this answer




























      1














      Yes, there's a very close equivalence between C#/SQL storing a single SqlConnection instance in a static variable and JS/MongoDB storing a single Db instance in a global variable. The basic pattern for JS/MongoDB in Azure Functions is (assuming you're up to date for async/await - alternatively you can use callbacks as per your linked article):



      // getDb.js

      let dbInstance;

      module.exports = async function() {
      if (!dbInstance) {
      dbInstance = await MongoClient.connect(uri);
      }
      return dbInstance;
      };

      // function.js

      const getDb = require('./getDb.js');

      module.exports = async function(context, trigger) {
      let db = await getDb();
      // ... do stuff with db ..
      };


      This will mean you only instantiate one Db object per host instance. Note this isn't one per Function App - if you're using a dedicated App Service Plan then there will be the number of instances you've specified in the plan, and if you're using a Consumption Plan then it'll vary depending on how busy your app is.






      share|improve this answer


























        1












        1








        1







        Yes, there's a very close equivalence between C#/SQL storing a single SqlConnection instance in a static variable and JS/MongoDB storing a single Db instance in a global variable. The basic pattern for JS/MongoDB in Azure Functions is (assuming you're up to date for async/await - alternatively you can use callbacks as per your linked article):



        // getDb.js

        let dbInstance;

        module.exports = async function() {
        if (!dbInstance) {
        dbInstance = await MongoClient.connect(uri);
        }
        return dbInstance;
        };

        // function.js

        const getDb = require('./getDb.js');

        module.exports = async function(context, trigger) {
        let db = await getDb();
        // ... do stuff with db ..
        };


        This will mean you only instantiate one Db object per host instance. Note this isn't one per Function App - if you're using a dedicated App Service Plan then there will be the number of instances you've specified in the plan, and if you're using a Consumption Plan then it'll vary depending on how busy your app is.






        share|improve this answer













        Yes, there's a very close equivalence between C#/SQL storing a single SqlConnection instance in a static variable and JS/MongoDB storing a single Db instance in a global variable. The basic pattern for JS/MongoDB in Azure Functions is (assuming you're up to date for async/await - alternatively you can use callbacks as per your linked article):



        // getDb.js

        let dbInstance;

        module.exports = async function() {
        if (!dbInstance) {
        dbInstance = await MongoClient.connect(uri);
        }
        return dbInstance;
        };

        // function.js

        const getDb = require('./getDb.js');

        module.exports = async function(context, trigger) {
        let db = await getDb();
        // ... do stuff with db ..
        };


        This will mean you only instantiate one Db object per host instance. Note this isn't one per Function App - if you're using a dedicated App Service Plan then there will be the number of instances you've specified in the plan, and if you're using a Consumption Plan then it'll vary depending on how busy your app is.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 22 '18 at 14:49









        MarkXAMarkXA

        3,0711114




        3,0711114






























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