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// v1.1.2 |
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// |
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// this lambda is the one automatically created by AWS |
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// when creating a CWL to ES stream using the AWS Console. |
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// I just added the `endpoint` variable handling. |
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// |
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var https = require('https'); |
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var zlib = require('zlib'); |
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var crypto = require('crypto'); |
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const ENV = process.env; |
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var endpoint = ENV.es_endpoint; |
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exports.handler = function(input, context) { |
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// decode input from base64 |
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var zippedInput = new Buffer(input.awslogs.data, 'base64'); |
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// decompress the input |
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zlib.gunzip(zippedInput, function(error, buffer) { |
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if (error) { context.fail(error); return; } |
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// parse the input from JSON |
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var awslogsData = JSON.parse(buffer.toString('utf8')); |
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// transform the input to Elasticsearch documents |
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var elasticsearchBulkData = transform(awslogsData); |
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// skip control messages |
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if (!elasticsearchBulkData) { |
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console.log('Received a control message'); |
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context.succeed('Control message handled successfully'); |
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return; |
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} |
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// post documents to the Amazon Elasticsearch Service |
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post(elasticsearchBulkData, function(error, success, statusCode, failedItems) { |
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console.log('Response: ' + JSON.stringify({ |
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"statusCode": statusCode |
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})); |
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if (error) { |
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console.log('Error: ' + JSON.stringify(error, null, 2)); |
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if (failedItems && failedItems.length > 0) { |
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console.log("Failed Items: " + |
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JSON.stringify(failedItems, null, 2)); |
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} |
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context.fail(JSON.stringify(error)); |
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} else { |
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console.log('Success: ' + JSON.stringify(success)); |
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context.succeed('Success'); |
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} |
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}); |
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}); |
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}; |
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function transform(payload) { |
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if (payload.messageType === 'CONTROL_MESSAGE') { |
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return null; |
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} |
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var bulkRequestBody = ''; |
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payload.logEvents.forEach(function(logEvent) { |
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var timestamp = new Date(1 * logEvent.timestamp); |
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// index name format: cwl-YYYY.MM.DD |
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var indexName = [ |
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'cwl-' + timestamp.getUTCFullYear(), // year |
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('0' + (timestamp.getUTCMonth() + 1)).slice(-2), // month |
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('0' + timestamp.getUTCDate()).slice(-2) // day |
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].join('.'); |
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var source = buildSource(logEvent.message, logEvent.extractedFields); |
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source['@id'] = logEvent.id; |
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source['@timestamp'] = new Date(1 * logEvent.timestamp).toISOString(); |
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source['@message'] = logEvent.message; |
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source['@owner'] = payload.owner; |
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source['@log_group'] = payload.logGroup; |
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source['@log_stream'] = payload.logStream; |
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var action = { "index": {} }; |
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action.index._index = indexName; |
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action.index._type = payload.logGroup; |
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action.index._id = logEvent.id; |
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bulkRequestBody += [ |
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JSON.stringify(action), |
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JSON.stringify(source), |
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].join('\n') + '\n'; |
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}); |
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return bulkRequestBody; |
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} |
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function buildSource(message, extractedFields) { |
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if (extractedFields) { |
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var source = {}; |
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for (var key in extractedFields) { |
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if (extractedFields.hasOwnProperty(key) && extractedFields[key]) { |
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var value = extractedFields[key]; |
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if (isNumeric(value)) { |
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source[key] = 1 * value; |
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continue; |
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} |
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jsonSubString = extractJson(value); |
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if (jsonSubString !== null) { |
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source['$' + key] = JSON.parse(jsonSubString); |
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} |
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source[key] = value; |
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} |
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} |
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return source; |
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} |
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jsonSubString = extractJson(message); |
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if (jsonSubString !== null) { |
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return JSON.parse(jsonSubString); |
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} |
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return {}; |
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} |
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function extractJson(message) { |
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var jsonStart = message.indexOf('{'); |
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if (jsonStart < 0) return null; |
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var jsonSubString = message.substring(jsonStart); |
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return isValidJson(jsonSubString) ? jsonSubString : null; |
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} |
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function isValidJson(message) { |
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try { |
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JSON.parse(message); |
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} catch (e) { return false; } |
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return true; |
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} |
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function isNumeric(n) { |
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return !isNaN(parseFloat(n)) && isFinite(n); |
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} |
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function post(body, callback) { |
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var requestParams = buildRequest(endpoint, body); |
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var request = https.request(requestParams, function(response) { |
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var responseBody = ''; |
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response.on('data', function(chunk) { |
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responseBody += chunk; |
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}); |
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response.on('end', function() { |
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var info = JSON.parse(responseBody); |
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var failedItems; |
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var success; |
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if (response.statusCode >= 200 && response.statusCode < 299) { |
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failedItems = info.items.filter(function(x) { |
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return x.index.status >= 300; |
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}); |
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success = { |
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"attemptedItems": info.items.length, |
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"successfulItems": info.items.length - failedItems.length, |
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"failedItems": failedItems.length |
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}; |
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} |
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var error = response.statusCode !== 200 || info.errors === true ? { |
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"statusCode": response.statusCode, |
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"responseBody": responseBody |
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} : null; |
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callback(error, success, response.statusCode, failedItems); |
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}); |
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}).on('error', function(e) { |
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callback(e); |
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}); |
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request.end(requestParams.body); |
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} |
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function buildRequest(endpoint, body) { |
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var endpointParts = endpoint.match(/^([^\.]+)\.?([^\.]*)\.?([^\.]*)\.amazonaws\.com$/); |
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var region = endpointParts[2]; |
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var service = endpointParts[3]; |
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var datetime = (new Date()).toISOString().replace(/[:\-]|\.\d{3}/g, ''); |
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var date = datetime.substr(0, 8); |
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var kDate = hmac('AWS4' + process.env.AWS_SECRET_ACCESS_KEY, date); |
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var kRegion = hmac(kDate, region); |
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var kService = hmac(kRegion, service); |
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var kSigning = hmac(kService, 'aws4_request'); |
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var request = { |
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host: endpoint, |
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method: 'POST', |
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path: '/_bulk', |
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body: body, |
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headers: { |
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'Content-Type': 'application/json', |
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'Host': endpoint, |
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'Content-Length': Buffer.byteLength(body), |
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'X-Amz-Security-Token': process.env.AWS_SESSION_TOKEN, |
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'X-Amz-Date': datetime |
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} |
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}; |
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var canonicalHeaders = Object.keys(request.headers) |
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.sort(function(a, b) { return a.toLowerCase() < b.toLowerCase() ? -1 : |
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1; }) |
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.map(function(k) { return k.toLowerCase() + ':' + request.headers[k]; }) |
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.join('\n'); |
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var signedHeaders = Object.keys(request.headers) |
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.map(function(k) { return k.toLowerCase(); }) |
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.sort() |
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.join(';'); |
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var canonicalString = [ |
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request.method, |
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request.path, '', |
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canonicalHeaders, '', |
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signedHeaders, |
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hash(request.body, 'hex'), |
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].join('\n'); |
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var credentialString = [ date, region, service, 'aws4_request' ].join('/'); |
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var stringToSign = [ |
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'AWS4-HMAC-SHA256', |
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datetime, |
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credentialString, |
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hash(canonicalString, 'hex') |
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] .join('\n'); |
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request.headers.Authorization = [ |
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'AWS4-HMAC-SHA256 Credential=' + process.env.AWS_ACCESS_KEY_ID + '/' + credentialString, |
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'SignedHeaders=' + signedHeaders, |
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'Signature=' + hmac(kSigning, stringToSign, 'hex') |
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].join(', '); |
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return request; |
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} |
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function hmac(key, str, encoding) { |
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return crypto.createHmac('sha256', key).update(str, |
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'utf8').digest(encoding); |
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} |
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function hash(str, encoding) { |
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return crypto.createHash('sha256').update(str, 'utf8').digest(encoding); |
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} |
Just wanted to drop you a note letting you know I appreciate you sharing the code. It helped kick start my own work. I'm using a VPC endpoint to access my Elasticsearch cluster so you have make some minor modifications to make it work. One is to expand the policy to allow for the creation of some network objects.
another is to use fill in the
vpc_config
block of theaws_lambda_function
resource with your subnet and security group ids.