Documentation
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Overview ¶
Package workerproto is the server's half of the Worker protocol handshake (ADR-0535 §3): which protocol versions this server speaks, and the Worker Type a Worker Instance reports running.
A Worker Instance names both on every poll — the job poll and the query poll — so a server that restarted, or an instance that was upgraded underneath it, is never working from a stale answer. Nothing here is durable: the handshake is runtime topology, kept in the Workers view and gone with a restart, like the rest of what a poll reports.
Compatibility rule ¶
The protocol has a major version. Within a major version every change is additive: a new request field is optional and ignored by a server that does not know it, a new response field is ignored by a client that does not know it. A change a client or a server could not ignore is a new major version.
A server accepts the current major version and the one before it, so a fleet of Worker Instances can be upgraded after the server rather than with it, for at least one release. A poll that names no version is version 1: that is every client from before the handshake. A poll that names a version the server does not accept is refused with 400 naming the versions it does, and every answer carries those versions in Header, so a newer client can tell an older server from a broken one.
Index ¶
Constants ¶
const Current = 1
Current is the protocol major version this server speaks natively.
const Header = "X-Atlas-Worker-Protocol"
Header names the response header listing the supported versions, comma-separated.
Variables ¶
var HeaderValue = func() string { parts := make([]string, len(supported)) for i, v := range supported { parts[i] = strconv.Itoa(v) } return strings.Join(parts, ",") }()
HeaderValue is Header's value on every answer to a Worker poll.
Source Files