Add prefix

Prepend a fixed path prefix to incoming requests before forwarding them to the backend. The reverse of Strip prefix.

The typical use case is exposing a sub-path of an existing app under a dedicated subdomain — e.g. serving example.com/foo/* from a separate foo.example.com host.

Label

labels:
  - "sozune.http.<svc>.addPrefix=<prefix>"

A leading slash is added if missing, and any trailing slash is removed. addPrefix=foo, addPrefix=/foo, and addPrefix=/foo/ all produce the same result.

Example

labels:
  - "sozune.http.expats.host=expats.example.com"
  - "sozune.http.expats.addPrefix=/foo"

Incoming request	Forwarded to backend
`/`	`/foo`
`/bar`	`/foo/bar`
`/bar/baz`	`/foo/bar/baz`

Behaviour

Without a path matcher, every request matches and the prefix is prepended verbatim.
With a path=/api matcher, only requests under /api are routed; the prefix is then prepended to the full path.
With an exact path matcher, the rewrite is static (addPrefix=/foo + path=/health → backend receives /foo/health).
addPrefix and stripPrefix are mutually exclusive. If both are set, addPrefix wins and a warning is logged.

Provider support

Provider	Supported	How
Docker / Swarm / Podman	yes	`sozune.http.<svc>.addPrefix=/foo` label
Nomad	yes	same label, declared as a Nomad tag
HTTP provider	yes	`add_prefix` field on the entrypoint JSON
YAML config file	yes	`add_prefix` field on the entrypoint
REST API	yes	`add_prefix` field on the entrypoint payload
Kubernetes (Ingress)	no — coming with the upcoming Gateway API provider

Notes

The path is forwarded as-is to the backend — Sōzune does not rewrite Location headers, canonical tags, or absolute URLs returned by the backend. If the backend embeds absolute paths in its responses, the rewrite must be coordinated on the backend side.
Internally, Sōzune translates the prefix into a regex matcher with a capture, plus a rewrite_path template on the Sōzu frontend.