Mixer enables extensible policy enforcement and control within the Istio service mesh. It is responsible for insulating the proxy (Envoy) from details of the current execution environment and the intricacies of infrastructure backends.

Mixer provides three distinct features:

• Precondition Checking. Enables callers to verify a number of preconditions before responding to an incoming request from a service consumer. Preconditions can include whether the service consumer is properly authenticated, is on the service's whitelist, passes ACL checks, and more.

• Quota Management. Enables services to allocate and free quota on a number of dimensions, Quotas are used as a relatively simple resource management tool to provide some fairness between service consumers when contending for limited resources.

• Telemetry Reporting. Enables services to produce logging, monitoring, tracing and billing streams intended for the service producer itself as well as for its consumers.

Learn more about Mixer here.

Mixer's Adapter Developer's Guide presents everything you need to know about extending Mixer to provide support for new backends through the development of new adapters.

Mixer's Template Developer's Guide presents everything you need to know about you can create new templates to define whole new categories of adapters.