Rather than writing something from the ground up maybe check out something like Munin where you should be able to write some plugins easily to capture what you want to track. - Source: Reddit / about 1 month ago
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Eclipse Memory Analyzer - The Eclipse Foundation - home to a global community, the Eclipse IDE, Jakarta EE and over 350 open source projects, including runtimes, tools and frameworks.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.