A single distribution of libraries that automatically collects traces and metrics from your app, displays them locally, and sends them to any analysis tool.

The key features of OpenCensus include:

• Standard wire protocols and consistent APIs for handling trace and metric data.
• A single set of libraries for many languages, including Java, C++, Go, .Net, Python, PHP, Node.js, Erlang, and Ruby.
• Included integrations with web and RPC frameworks, making traces and metrics available out of the box.
• Included exporters for storage and analysis tools. Right now the list includes Zipkin, Prometheus, Datadog, Stackdriver, and Azure App Insights.
• Full open source availability for additional integrations and export options.
• No additional server or daemon is required to support OpenCensus.
• In process debugging: an optional agent for displaying request and metrics data on instrumented hosts.

Graphite does two things:

1) Store numeric time-series data
2) Render graphs of this data on demand

What Graphite does not do is collect data for you, however there are some tools out there that know how to send data to graphite. Even though it often requires a little code, sending data to Graphite is very simple.