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| 1 | +// tslint:disable:no-console |
| 2 | +import AWS = require('aws-sdk'); |
| 3 | + |
| 4 | +/** |
| 5 | + * Creates a log group and doesn't throw if it exists. |
| 6 | + * |
| 7 | + * @param logGroupName the name of the log group to create |
| 8 | + */ |
| 9 | +async function createLogGroupSafe(logGroupName: string) { |
| 10 | + try { // Try to create the log group |
| 11 | + const cloudwatchlogs = new AWS.CloudWatchLogs({ apiVersion: '2014-03-28' }); |
| 12 | + await cloudwatchlogs.createLogGroup({ logGroupName }).promise(); |
| 13 | + } catch (e) { |
| 14 | + if (e.code !== 'ResourceAlreadyExistsException') { |
| 15 | + throw e; |
| 16 | + } |
| 17 | + } |
| 18 | +} |
| 19 | + |
| 20 | +/** |
| 21 | + * Puts or deletes a retention policy on a log group. |
| 22 | + * |
| 23 | + * @param logGroupName the name of the log group to create |
| 24 | + * @param retentionInDays the number of days to retain the log events in the specified log group. |
| 25 | + */ |
| 26 | +async function setRetentionPolicy(logGroupName: string, retentionInDays?: number) { |
| 27 | + const cloudwatchlogs = new AWS.CloudWatchLogs({ apiVersion: '2014-03-28' }); |
| 28 | + if (!retentionInDays) { |
| 29 | + await cloudwatchlogs.deleteRetentionPolicy({ logGroupName }).promise(); |
| 30 | + } else { |
| 31 | + await cloudwatchlogs.putRetentionPolicy({ logGroupName, retentionInDays }).promise(); |
| 32 | + } |
| 33 | +} |
| 34 | + |
| 35 | +export async function handler(event: AWSLambda.CloudFormationCustomResourceEvent, context: AWSLambda.Context) { |
| 36 | + try { |
| 37 | + console.log(JSON.stringify(event)); |
| 38 | + |
| 39 | + // The target log group |
| 40 | + const logGroupName = event.ResourceProperties.LogGroupName; |
| 41 | + |
| 42 | + if (event.RequestType === 'Create' || event.RequestType === 'Update') { |
| 43 | + // Act on the target log group |
| 44 | + await createLogGroupSafe(logGroupName); |
| 45 | + await setRetentionPolicy(logGroupName, parseInt(event.ResourceProperties.RetentionInDays, 10)); |
| 46 | + |
| 47 | + if (event.RequestType === 'Create') { |
| 48 | + // Set a retention policy of 1 day on the logs of this function. The log |
| 49 | + // group for this function should already exist at this stage because we |
| 50 | + // already logged the event but due to the async nature of Lambda logging |
| 51 | + // there could be a race condition. So we also try to create the log group |
| 52 | + // of this function first. |
| 53 | + await createLogGroupSafe(`/aws/lambda/${context.functionName}`); |
| 54 | + await setRetentionPolicy(`/aws/lambda/${context.functionName}`, 1); |
| 55 | + } |
| 56 | + } |
| 57 | + |
| 58 | + await respond('SUCCESS', 'OK', logGroupName); |
| 59 | + } catch (e) { |
| 60 | + console.log(e); |
| 61 | + |
| 62 | + await respond('FAILED', e.message, event.ResourceProperties.LogGroupName); |
| 63 | + } |
| 64 | + |
| 65 | + function respond(responseStatus: string, reason: string, physicalResourceId: string) { |
| 66 | + const responseBody = JSON.stringify({ |
| 67 | + Status: responseStatus, |
| 68 | + Reason: reason, |
| 69 | + PhysicalResourceId: physicalResourceId, |
| 70 | + StackId: event.StackId, |
| 71 | + RequestId: event.RequestId, |
| 72 | + LogicalResourceId: event.LogicalResourceId, |
| 73 | + Data: {} |
| 74 | + }); |
| 75 | + |
| 76 | + console.log('Responding', responseBody); |
| 77 | + |
| 78 | + const parsedUrl = require('url').parse(event.ResponseURL); |
| 79 | + const requestOptions = { |
| 80 | + hostname: parsedUrl.hostname, |
| 81 | + path: parsedUrl.path, |
| 82 | + method: 'PUT', |
| 83 | + headers: { 'content-type': '', 'content-length': responseBody.length } |
| 84 | + }; |
| 85 | + |
| 86 | + return new Promise((resolve, reject) => { |
| 87 | + try { |
| 88 | + const request = require('https').request(requestOptions, resolve); |
| 89 | + request.on('error', reject); |
| 90 | + request.write(responseBody); |
| 91 | + request.end(); |
| 92 | + } catch (e) { |
| 93 | + reject(e); |
| 94 | + } |
| 95 | + }); |
| 96 | + } |
| 97 | +} |
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