Policy and Telemetry Rules
Action describes which Handler to invoke and what data to pass to it for processing.
The following example instructs Mixer to invoke ‘prometheus-handler’ handler and pass it the object constructed using the instance ‘RequestCountByService’
handler: prometheus-handler instances: - RequestCountByService
AttributeManifest describes a set of Attributes produced by some component of an Istio deployment.
AttributeInfo describes the schema of an Istio
attributes to describe runtime activities of Istio services. An Istio attribute carries a specific piece of information about an activity, such as the error code of an API request, the latency of an API request, or the original IP address of a TCP connection. The attributes are often generated and consumed by different services. For example, a frontend service can generate an authenticated user attribute and pass it to a backend service for access control purpose.
To simplify the system and improve developer experience, Istio uses shared attribute definitions across all components. For example, the same authenticated user attribute will be used for logging, monitoring, analytics, billing, access control, auditing. Many Istio components provide their functionality by collecting, generating, and operating on attributes. For example, the proxy collects the error code attribute, and the logging stores it into a log.
Each Istio attribute must conform to an
AttributeInfo in an
AttributeManifest in the current Istio deployment at runtime. An
AttributeInfo is used to define an attribute’s metadata: the type of its value and a detailed description that explains the semantics of the attribute type. Each attribute’s name is globally unique; in other words an attribute name can only appear once across all manifests.
The runtime presentation of an attribute is intentionally left out of this specification, because passing attribute using JSON, XML, or Protocol Buffers does not change the semantics of the attribute. Different implementations can choose different representations based on their needs.
Because many systems already have REST APIs, it makes sense to define a standard HTTP mapping for Istio attributes that are compatible with typical REST APIs. The design is to map one attribute to one HTTP header, the attribute name and value becomes the HTTP header name and value. The actual encoding scheme will be decided later.
Handler allows the operator to configure a specific adapter implementation. Each adapter implementation defines its own
In the following example we define a
metrics handler using the Mixer’s prepackaged prometheus adapter. This handler doesn’t require any parameters.
name: prometheus-handler adapter: prometheus params:
An Instance tells Mixer how to create instances for particular template.
Instance is defined by the operator. Instance is defined relative to a known template. Their purpose is to tell Mixer how to use attributes or literals to produce instances of the specified template at runtime.
The following example instructs Mixer to construct an instance associated with template ‘istio.mixer.adapter.metric.Metric’. It provides a mapping from the template’s fields to expressions. Instances produced with this instance can be referenced by Actions using name ‘RequestCountByService’.
- name: RequestCountByService template: istio.mixer.adapter.metric.Metric params: value: 1 dimensions: source: source.service destination_ip: destination.ip
A Rule is a selector and a set of intentions to be executed when the selector is
The following example instructs Mixer to invoke ‘prometheus-handler’ handler for all services and pass it the instance constructed using the ‘RequestCountByService’ instance.
- match: destination.service == "*" actions: - handler: prometheus-handler instances: - RequestCountByService
Struct represents a structured data value, consisting of fields which map to dynamically typed values. In some languages,
Struct might be supported by a native representation. For example, in scripting languages like JS a struct is represented as an object. The details of that representation are described together with the proto support for the language.
The JSON representation for
Struct is JSON object.