Merge pull request #13 from alertlogic/update_function_config

lambda config update

Author: tomdos

al_aws.js

@@ -11,6 +11,7 @@
 
 const AWS = require('aws-sdk');
 const moment = require('moment');
+const async = require('async');
 
 const AWS_STATISTICS_PERIOD_MINUTES = 15;
 const MAX_ERROR_MSG_LEN = 1024;
@@ -33,6 +34,40 @@ var selfUpdate = function (callback) {
     });
 };
 
+var getS3ConfigChanges = function(callback) {
+    var s3 = new AWS.S3();
+
+    var params = {
+        Bucket: process.env.aws_lambda_s3_bucket,
+        Key: process.env.aws_lambda_update_config_name
+    };
+    s3.getObject(params, function(err, object) {
+        if (err) {
+            return callback(err);
+        } else {
+            try  {
+                let config = JSON.parse(object.Body.toString());
+                return callback(null, config);
+            } catch(ex) {
+                return callback('Unable to parse config cahnges.')
+            }
+        }
+    });
+};
+
+var getLambdaConfig = function(callback) {
+    var lambda = new AWS.Lambda();
+    var params = {
+        FunctionName: process.env.AWS_LAMBDA_FUNCTION_NAME
+    };
+
+    lambda.getFunctionConfiguration(params, callback);
+};
+
+var updateLambdaConfig = function(config, callback) {
+    var lambda = new AWS.Lambda();
+    lambda.updateFunctionConfiguration(config, callback);
+};
 
 //DEPRECATED FUNCTION
 //please use statistics_templates.js instead
@@ -126,13 +161,16 @@ var setEnv = function(vars, callback) {
 
 module.exports = {
     selfUpdate : selfUpdate,
+    getS3ConfigChanges : getS3ConfigChanges,
+    updateLambdaConfig : updateLambdaConfig,
+    getLambdaConfig : getLambdaConfig,
     arnToName : arnToName,
     arnToAccId : arnToAccId,
     setEnv : setEnv,
-
+    
     //DEPRECATED FUNCTIONS
     //please use statistics_templates.js instead
     getMetricStatistics : getMetricStatistics,
     getLambdaMetrics : getLambdaMetrics,
-    getKinesisMetrics : getKinesisMetrics
+    getKinesisMetrics : getKinesisMetrics,
 };

al_aws_collector.js

@@ -14,6 +14,7 @@ const moment = require('moment');
 const zlib = require('zlib');
 const async = require('async');
 const response = require('cfn-response');
+const deepEqual = require('deep-equal');
 
 const m_alCollector = require('al-collector-js');
 const m_alAws = require('./al_aws');
@@ -246,10 +247,116 @@ class AlAwsCollector {
         ],
         callback);
     }
+    
+    update(callback) {
+        let collector = this;
+
+        async.waterfall([
+            collector.selfUpdate,
+            function(asyncCallback) {
+                // Run config update only if the config file is known
+                if (process.env.aws_lambda_update_config_name) {
+                    collector.selfConfigUpdate(asyncCallback);
+                } else {
+                    asyncCallback(null)
+                }
+            }
+        ], callback);
+    }
 
     selfUpdate(callback) {
         m_alAws.selfUpdate(callback);
     }
+    
+    selfConfigUpdate(callback) {
+        let collector = this;
+        
+        async.waterfall([
+            function(asyncCallback) {
+                m_alAws.getS3ConfigChanges(function(err, config) {
+                    asyncCallback(err, config);
+                });
+            },
+            function(newValues, asyncCallback) {
+                m_alAws.getLambdaConfig(function(err, currentConfig) {
+                    asyncCallback(err, newValues, currentConfig);
+                });
+            },
+            function(newValues, currentConfig, asyncCallback) {
+                collector._applyConfigChanges(newValues, currentConfig, function(err, newConfig) {
+                    asyncCallback(err, newConfig, currentConfig);
+                });
+            },
+            function(newConfig, currentConfig, asyncCallback) {
+                if (collector._isConfigDifferent(newConfig, currentConfig)) {
+                    let updateConfig = collector._filterDisallowedConfigParams(newConfig);
+                    m_alAws.updateLambdaConfig(updateConfig, asyncCallback);
+                } else {
+                    asyncCallback(null);
+                }
+            }
+        ],
+        function(err, config) {
+            if (err) {
+                console.info('Lambda self-update config error: ', err);
+            } else {
+                if (config !== undefined) {
+                    console.info('Lambda self-update config successful. Config: ', config);
+                } else {
+                    console.info('Lambda self-update config nothing to update');
+                }
+            }
+            callback(err, config);
+        });
+    }
+
+    _applyConfigChanges(newValues, config, callback) {
+        var jsonConfig = JSON.stringify(config);
+        var newConfig = JSON.parse(jsonConfig); 
+        
+        try {
+            Object.keys(newValues).forEach(
+                function(item) {
+                    let path = newValues[item]['path'];
+                    let value = newValues[item]['value'];
+                    this._changeObject(newConfig, path, value);
+                }, this); //lexical scoping
+            return callback(null, newConfig);
+        }
+        catch(ex) {
+            return callback('Unable to apply new config values');
+        }
+    }
+
+    _changeObject(obj, path, value) {
+        if (typeof path == 'string') {
+            return this._changeObject(obj, path.split('.'), value);
+        }
+        else if (path.length == 1) {
+            return obj[path[0]] = value;
+        } else {
+            return this._changeObject(obj[path[0]], path.slice(1), value);
+        }
+    }
+
+    _isConfigDifferent(config1, config2) {
+        return !deepEqual(config1, config2);
+    }
+
+    _filterDisallowedConfigParams(config) {
+        var newConfig = JSON.parse(JSON.stringify(config));
+        // These are not either allowed to update or we don't have enough permission.
+        delete(newConfig.FunctionArn);
+        delete(newConfig.Role);
+        delete(newConfig.CodeSize);
+        delete(newConfig.LastModified);
+        delete(newConfig.CodeSha256);
+        delete(newConfig.Version);
+        if (newConfig.VpcConfig)
+            delete(newConfig.VpcConfig.VpcId);
+        delete(newConfig.MasterArn);
+        return newConfig;
+    }
 }
 
 module.exports = AlAwsCollector;

package.json

@@ -24,7 +24,8 @@
     "al-collector-js": "git://github.com/alertlogic/al-collector-js#master",
     "cfn-response": "*",
     "async": "*",
-    "moment": "^2.19.2"
+    "moment": "^2.19.2",
+    "deep-equal": "*"
   },
   "author": "Alert Logic Inc."
 }