This documents defines the vocabulary for logs to be used across OpenTelemetry project.
We need a common language and common understanding of terms that we use to avoid the chaos experienced by the builders of the Tower of Babel.
OpenTelemetry specification already contains a vocabulary for Traces, Metrics and other relevant concepts.
This proposal is to add the following concepts to the vocabulary.
A recording of an event. Typically the record includes a timestamp indicating when the event happened as well as other data that describes what happened, where it happened, etc.
Also known as Log Entry.
Sometimes used to refer to a collection of Log Records. May be ambiguous, since
people also sometimes use Log to refer to a single Log Record, thus this
term should be used carefully and in the context where ambiguity is possible
additional qualifiers should be used (e.g. Log Record).
Log Records embedded inside a Span
object, in the Events list.
Log Records that are not embedded inside a Span and are recorded elsewhere.
Key/value pairs contained in a Log Record.
Logs that are recorded in a format which has a well-defined structure that allows
to differentiate between different elements of a Log Record (e.g. the Timestamp,
the Attributes, etc). The Syslog protocol (RFC 5425),
for example, defines a structured-data format.
Logs recorded in text files, often one line per log record (although multiline records are possible too). There is no common industry agreement whether logs written to text files in more structured formats (e.g. JSON files) are considered Flat File Logs or not. Where such distinction is important it is recommended to call it out specifically.