Category Archives: Uncategorized

webpack issues

may need to run ‘sudo npm install’ first install missing dependencies with `sudo npm install <DEP>` “` Module parse failed: /home/neil/Dropbox/w540-bak/bitbucket/sa-client-ui/src/app.js Unexpected token (199:40) You may need an appropriate loader to handle this file type. SyntaxError: Unexpected token (199:40) “` … Continue reading

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DynamoDB: An AttributeValue may not contain an empty string (Exception)

Problem com.amazonaws.AmazonServiceException: One or more parameter values were invalid: An AttributeValue may not contain an empty string (Service: AmazonDynamoDBv2; Solution This cryptic message basically says that dynamodb is not able to save fields with empty strings (or null) (a rather … Continue reading

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org.codehaus.mojo:nbm-maven-plugin: Module has friend dependency on but is not listed as a friend

Problem [ERROR] Failed to execute goal org.codehaus.mojo:nbm-maven-plugin:3.14:manifest (default-manifest) on project move: Module has friend dependency on org.netbeans.bootstrap but is not listed as a friend. -> [Help 1] Solution Add scope: provided; e.g.: <dependency> <groupId>org.netbeans.modules</groupId> <artifactId>org-netbeans-bootstrap</artifactId> <version>RELEASE81</version> <scope>provided</scope> </dependency>   keywords: … Continue reading

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Upgrading Gephi 0.8 to 0.9

Gephi’s API had a rather significant API changes; here are some tips for the upgrades. This nifty repo can get you started quickly: https://github.com/gephi/gephi-plugins This repo provides good examples of API usage: https://github.com/gephi/gephi-toolkit-demos API Changes AttributeColumn subGraphFitnessCol = model.getNodeTable().getColumn(FLD_SUBGRAPH_FITNESS, AttributeType.DOUBLE); -> Column … Continue reading

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Machine Learning Book Recommendations

I am often asked to recommend books on machine learning (ML).  Here is a WIP list of my recommendations: http://www.amazon.com/gp/registry/wishlist/1TLVK1WKJF47S/  

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Using AWS Lambda Alias with API Gateway

Using AWS lambda with specific alias through API Gateway; as described here with a command like: aws lambda add-permission –function-name arn:aws:lambda:us-east-1:xxxxxx:function:getData –source-arn arn:aws:execute-api:us-east-1:xxxxxx:t463p6g84d/*/POST/data –principal apigateway.amazonaws.com –statement-id  –action lambda:InvokeFunction Resulted in an error aws: error: argument operation: Invalid choice, valid choices are: … Continue reading

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AWS Lambda invoking from code

You can invoke a lambda from your code (details); you’d probably want to use the AWSLambdaAsyncClient. CAUTION: you have to be very careful not to make re-cursive calls (unless that is your intention); otherwise you might get into an infinite loop. … Continue reading

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DynamoDB: batch delete

Excerpt from my program; adapt as needed:   val client = new AmazonDynamoDBClient() val dynamo = new DynamoDB(client) val scanRequest = new ScanRequest() .withTableName(LocationRecord.TABLE_NAME) val items = client.scan(scanRequest).getItems items.grouped(25).foreach(group => { // DynamoDB: Member must have length less than or … Continue reading

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does not map a @DynamoDBHashKey attribute; ensure a public, zero-parameter get method/field is annotated

Problem: “` Class does not map a @DynamoDBHashKey attribute; ensure a public, zero-parameter get method/field is annotated com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMappingException: Class does not map a @DynamoDBHashKey attribute; ensure a public, zero-parameter get method/field is annotated at com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMappingsRegistry$Mappings.getHashKey(DynamoDBMappingsRegistry.java:245) at com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper.needAutoGenerateAssignableKey(DynamoDBMapper.java:682) at com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper.save(DynamoDBMapper.java:708) at … Continue reading

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AWS Lambda: extending execution time limit

Currently AWS Lambda limits execution time to 5 min.  However, in quite a few cases it is possible to overcome this limitation by simply re-invoking your function in an iterative manner.  Here are brief details. You can keep a tab … Continue reading

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