The Holy Java

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Archive for May, 2015

OS X: Using scutils to discover whether/what a web proxy is in use

Posted by Jakub Holý on May 7, 2015

When looking for ways to discover whether a proxy is being used by OS X, you will be typically pointed to

networksetup -getwebproxy

However that does not always work – for example when using “Auto Proxy Discovery” and/or “Automatic Proxy Configuration” with a proxy.pac file. scutils --proxy seems to detect all these cases (though it cannot give you the proxy when using auto config, I suppose):
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All-in-one Docker with Grafana, InfluxDB, and cloudwatch-to-graphite for AWS/Beanstalk monitoring

Posted by Jakub Holý on May 7, 2015

I have derived the Docker container docker-grafana-influxdb-cloudwatch that bundles Grafana dashboards, InfluxDB for metrics storage, and runs cloudwatch-to-graphite as a cron job to fetch selected metrics from AWS CloudWatch and feed them into the InfluxDB using its Graphite input plugin. It is configured so that you can run it in AWS Elastic Beanstalk (the main problem being that only a single port can be exposed – I therefore use Nginx to expose the InfluxDB API needed by Grafana at :80/db/).

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Hack: Quickly Verify That All Your Mocha/Chai Tests Have Valid Assertions

Posted by Jakub Holý on May 6, 2015

Chai is a popular Node/browser assertion library. However – as everything – it has its flaws. An important flaw is that it performs checks on property access – and if you e.g. misspell the name of an assertion, it will be just ignored (for there is no way for Chai to know that you tried to access a non-existent property). This may be fixed in the future with ES6 proxies but so far you risk having tests that actually do not test anything. Though you should of course always develop your tests so that they initially fail and thus you know they actually assert something :-).

Anyway, there is a neat quick way to verify that all your tests have at least one valid assertion – simply replace expect with expect.not.
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