BAAS-33449: add boilerplate snippets

Author: jwongmongodb

manifest.json

@@ -3,6 +3,9 @@
     {
       "metadata": "/snippets/functions/third-party/manifest.json"
     },
+    {
+      "metadata": "/snippets/functions/boilerplate/manifest.json"
+    },
     {
       "metadata": "/snippets/functions/mongodb-crud/manifest.json"
     },

snippets/functions/boilerplate/databaseTrigger.js

@@ -0,0 +1,40 @@
+exports = async function (changeEvent) {
+  // A Database Trigger will always call a function with a changeEvent.
+  // Documentation on ChangeEvents: https://www.mongodb.com/docs/manual/reference/change-events
+
+  // This sample function will listen for events and replicate them to a collection in a different Database
+
+  // Access the _id of the changed document:
+  const docId = changeEvent.documentKey._id;
+
+  // Get the MongoDB service you want to use (see "Linked Data Sources" tab)
+  const serviceName = "mongodb-atlas";
+  const databaseName = "other_db_name";
+  const collection = context.services
+    .get(serviceName)
+    .db(databaseName)
+    .collection(changeEvent.ns.coll);
+
+  // Get the "FullDocument" present in the Insert/Replace/Update ChangeEvents
+  try {
+    // If this is a "delete" event, delete the document in the other collection
+    if (changeEvent.operationType === "delete") {
+      await collection.deleteOne({ _id: docId });
+    }
+
+    // If this is an "insert" event, insert the document into the other collection
+    else if (changeEvent.operationType === "insert") {
+      await collection.insertOne(changeEvent.fullDocument);
+    }
+
+    // If this is an "update" or "replace" event, then replace the document in the other collection
+    else if (
+      changeEvent.operationType === "update" ||
+      changeEvent.operationType === "replace"
+    ) {
+      await collection.replaceOne({ _id: docId }, changeEvent.fullDocument);
+    }
+  } catch (err) {
+    console.log("error performing mongodb write: ", err.message);
+  }
+};

snippets/functions/boilerplate/eventbridgeErrorFunction.js

@@ -0,0 +1,18 @@
+exports = async function (error, changeEvent) {
+  // This sample function will log additional details if the error is not
+  // a DOCUMENT_TOO_LARGE error
+  if (error.code === "DOCUMENT_TOO_LARGE") {
+    console.log("Document too large error");
+
+    // Comment out the line below in order to skip this event and not suspend the Trigger
+    throw new Error(`Encountered error: ${error.code}`);
+  }
+
+  console.log("Error sending event to EventBridge");
+  console.log(`DB: ${changeEvent.ns.db}`);
+  console.log(`Collection: ${changeEvent.ns.coll}`);
+  console.log(`Operation type: ${changeEvent.operationType}`);
+
+  // Throw an error in your function to suspend the trigger and stop processing additional events
+  throw new Error(`Encountered error: ${error.message}`);
+};

snippets/functions/boilerplate/generalFunction.js

@@ -0,0 +1,47 @@
+exports = async function(arg){
+    // This default function will get a value and find a document in MongoDB
+    // To see plenty more examples of what you can do with functions see:
+    // https://www.mongodb.com/docs/atlas/app-services/functions/
+   
+   
+    // Find the name of the MongoDB service you want to use (see "Linked Data Sources" tab)
+    var serviceName = "mongodb-atlas";
+   
+   
+    // Update these to reflect your db/collection
+    var dbName = "db_name";
+    var collName = "coll_name";
+   
+   
+    // Get a collection from the context
+    var collection = context.services.get(serviceName).db(dbName).collection(collName);
+   
+   
+    var findResult;
+    try {
+      // Get a value from the context (see "Values" tab)
+      // Update this to reflect your value's name.
+      var valueName = "value_name";
+      var value = context.values.get(valueName);
+   
+   
+      // Execute a FindOne in MongoDB
+      findResult = await collection.findOne(
+        { owner_id: context.user.id, "fieldName": value, "argField": arg},
+      );
+   
+   
+    } catch(err) {
+      console.log("Error occurred while executing findOne:", err.message);
+   
+   
+      return { error: err.message };
+    }
+   
+   
+    // To call other named functions:
+    // var result = context.functions.execute("function_name", arg1, arg2);
+   
+   
+    return { result: findResult };
+   

snippets/functions/boilerplate/manifest.json

@@ -0,0 +1,31 @@
+{
+  "category": "Boilerplate Template by Function Type",
+  "categoryId": "4756072f-b3c7-4469-b038-cdf6b346789c",
+  "viewType": "functionSnippet",
+  "snippets": [
+    {
+      "id": "7c84ed29-b8b2-466c-af3d-c240889d3112",
+      "title": "Database Trigger",
+      "snippet": "/databaseTrigger.js",
+      "description": "Example shows a template for a DB trigger function, which always accepts a changeEvent in the header."
+    },
+    {
+      "id": "ba6113d7-5e52-48e4-8ab4-03df30c0d61a",
+      "title": "Scheduled Trigger",
+      "snippet": "/scheduledTrigger.js",
+      "description": "Shows an example of a Scheduled Trigger function, which will always call a function without arguments."
+    },
+    {
+      "id": "1dca4a58-c150-4a8e-b602-9edf5c338f3d",
+      "title": "General Function",
+      "snippet": "/generalFunction.js",
+      "description": "Example of a default function that will get a value and find a document in MongoDB, the parameters passed in the header differs from other templates."
+    },
+    {
+      "id": "b43b9abb-dde7-4389-880e-38ef995d501a",
+      "title": "Eventbridge Custom Error Function",
+      "snippet": "/eventbridgeErrorFunction.js",
+      "description": "Example of a custom error function, which takes in the error and changeEvent as arguments."
+    }
+  ]
+}

snippets/functions/boilerplate/scheduledTrigger.js

@@ -0,0 +1,21 @@
+exports = async function () {
+  // A Scheduled Trigger will always call a function without arguments.
+  // Documentation on Triggers: https://www.mongodb.com/docs/atlas/app-services/triggers/
+
+  // Functions run by Triggers are run as System users and have full access to Services, Functions, and MongoDB Data.
+
+  // Get the MongoDB service you want to use (see "Linked Data Sources" tab)
+  const serviceName = "mongodb-atlas";
+  const databaseName = "db_name";
+  const collectionName = "coll_name";
+  const collection = context.services
+    .get(serviceName)
+    .db(databaseName)
+    .collection(collectionName);
+
+  try {
+    const doc = await collection.findOne({ name: "mongodb" });
+  } catch (err) {
+    console.log("error performing mongodb findOne: ", err.message);
+  }
+};