Analysis Messages

3 minute read

Describes the structure of messages generated by Istio analyzers.

AnalysisMessageBase

AnalysisMessageBase describes some common information that is needed for all messages. All information should be static with respect to the error code.

Field	Description
`type` Type
`level` Level	Represents how severe a message is. Required.
`documentationUrl` string	A url pointing to the Istio documentation for this specific error type. Should be of the form `^http(s)?://(preliminary\.)?istio.io/docs/reference/config/analysis/` Required.

Type

A unique identifier for the type of message. Name is intended to be human-readable, code is intended to be machine readable. There should be a one-to-one mapping between name and code. (i.e. do not re-use names or codes between message types.)

Field	Description
`name` string	A human-readable name for the message type. e.g. “InternalError”, “PodMissingProxy”. This should be the same for all messages of the same type. Required.
`code` string	A 7 character code matching `^IST[0-9]{4}$` intended to uniquely identify the message type. (e.g. “IST0001” is mapped to the “InternalError” message type.) 0000-0100 are reserved. Required.

Level

The values here are chosen so that more severe messages get sorted higher, as well as leaving space in between to add more later

Name	Description
`UNKNOWN`	invalid, but included for proto compatibility for 0 values
`ERROR`
`WARNING`
`INFO`

AnalysisMessageWeakSchema

AnalysisMessageWeakSchema is the set of information that’s needed to define a weakly-typed schema. The purpose of this proto is to provide a mechanism for validating istio/istio/galley/pkg/config/analysis/msg/messages.yaml to make sure that we don’t allow committing underspecified types.

Field	Description
`messageBase` AnalysisMessageBase	Required
`description` string	A human readable description of what the error means. Required.
`template` string	A go-style template string (https://golang.org/pkg/fmt/#hdr-Printing) defining how to combine the args for a particular message into a log line. Required.
`args` ArgType[]	A description of the arguments for a particular message type

ArgType

Field	Description
`name` string	Required
`goType` string	Should be a golang type, used in code generation. Ideally this will change to a less language-pinned type before this gets out of alpha, but for compatibility with current istio/istio code it’s go_type for now.

GenericAnalysisMessage

GenericAnalysisMessage is an instance of an AnalysisMessage defined by a schema, whose metaschema is AnalysisMessageWeakSchema. (Names are hard.) Code should be able to perform validation of arguments as needed by using the message type information to look at the AnalysisMessageWeakSchema and examine the list of args at runtime. Developers can also create stronger-typed versions of GenericAnalysisMessage for well-known and stable message types.

Field	Description
`messageBase` AnalysisMessageBase	Required
`args` Struct	Any message-type specific arguments that need to get codified. Optional.
`resourcePaths` string[]	A list of strings specifying the resource identifiers that were the cause of message generation. A “path” here is a (NAMESPACE/)?RESOURCETYPE/NAME tuple that uniquely identifies a particular resource. There doesn’t seem to be a single concept for this, but this is intuitively taken from https://kubernetes.io/docs/reference/using-api/api-concepts/#standard-api-terminology At least one is required.

InternalErrorAnalysisMessage

InternalErrorAnalysisMessage is a strongly-typed message representing some error in Istio code that prevented us from performing analysis at all.

Field	Description
`messageBase` AnalysisMessageBase	Required
`detail` string	Any detail regarding specifics of the error. Should be human-readable.