Closes [DOCS-351](https://linear.app/codercom/issue/DOCS-351).
> [!WARNING]
> **DO NOT MERGE** until
[DOCS-349](https://linear.app/codercom/issue/DOCS-349)
([coder.com#877](https://github.com/coder/coder.com/pull/877)) has
shipped to production and baked for at least one Vercel cycle.
>
> Without DOCS-349, the relative links in this PR resolve to broken
docs-route URLs (`/docs/helm/coder/values.yaml` -> 404) instead of
GitHub URLs tagged with the displayed docs version. DOCS-349 fixes the
rewriter to classify these as GitHub blob/tree URLs with the page's
resolved ref.
## TL;DR
Converts 121 absolute
`https://github.com/coder/coder/(blob|tree)/main/<path>` links across 39
docs markdown files to relative paths. After this lands AND DOCS-349
deploys, every one of these links will follow the displayed docs version
(mainline tag on bare URLs, explicit tag on `/@vX.Y.Z/`, `main` on
`/@main/`) instead of always pointing to `main`.
## Why
Today a reader on `/docs/@v2.30.0/install/docker` follows a
`compose.yaml` link and arrives at `main`'s `compose.yaml`, which
doesn't necessarily match what the docs page describes. Helm values,
Terraform templates, and source-code references in particular drift
across versions. The fix is to let the coder.com rewriter substitute the
page's resolved ref into the URL; that only works on relative links.
## Example payoff (post-DOCS-349)
| URL | Today (absolute, always `main`) | After (relative + rewriter) |
|---|---|---|
| `/docs/install/docker` |
`https://github.com/coder/coder/blob/main/compose.yaml` |
`https://github.com/coder/coder/blob/v2.34.1/compose.yaml` (today's
mainline) |
| `/docs/@v2.30.0/install/docker` | same as above |
`https://github.com/coder/coder/blob/v2.30.0/compose.yaml` |
| `/docs/@main/install/docker` | same as above |
`https://github.com/coder/coder/blob/main/compose.yaml` |
## Scope
- **121 conversions** across **39 files**.
- Verb breakdown: `tree/main` (directories) and `blob/main` (files),
both flipped to relative paths.
- Line anchors (`#L23-L24`) and query strings preserved verbatim.
- Conversion is mechanical: relative path computed from the doc file's
directory to the target via `os.path.relpath`. Any path starting at the
same directory or below gets a `./` prefix; otherwise `../` chains.
## Rebased on main
The branch was rebased onto `main` after the DOCS-350 hotfix
([#26339](https://github.com/coder/coder/pull/26339)) merged. The hotfix
repointed 3 `docs-backend-contrib-guide` refs in `backend.md` to `main`,
which then needed the same `main` -> relative conversion this PR is
doing for the other 121 links. The conflict was resolved by reapplying
the mechanical conversion to `backend.md` after taking the hotfix's
content. Net result: those 3 links land here as relative, same as
everything else. New HEAD `3f501cb622`.
## Inline fix folded in: dead `nix` link
- `docs/about/contributing/CONTRIBUTING.md:7` -> `../../../nix`
The original absolute URL `https://github.com/coder/coder/tree/main/nix`
already returned 404 today. Repointed to `flake.nix` (modern Nix
entrypoint, what the prose "Nix environment" semantically refers to).
Closes [DOCS-357](https://linear.app/codercom/issue/DOCS-357) here since
the `check-docs` Linkspector job surfaced it during rebase; cheaper to
fix inline than in a separate single-line PR.
## Out of scope (filed separately)
- [DOCS-350](https://linear.app/codercom/issue/DOCS-350): 3 dead
`docs-backend-contrib-guide` branch refs in `backend.md`
([#26339](https://github.com/coder/coder/pull/26339), merged).
- [DOCS-352](https://linear.app/codercom/issue/DOCS-352): 10 SHA-pinned
`(blob|tree)/<sha>` links pending intent review.
- [DOCS-355](https://linear.app/codercom/issue/DOCS-355): code-server
analog (4 absolute `(blob|tree)/main` links in `coder/code-server`).
- [DOCS-356](https://linear.app/codercom/issue/DOCS-356): 2 upstream
content bugs in `coder/code-server/docs/CONTRIBUTING.md` (independent of
this PR).
## Not triggering `/coder-agents-review`
Docs-only edit; per `AGENTS.md` the bot review is reserved for
product/CI changes.
## Pre-mortem
| Concern | Mitigation |
|---|---|
| Merging before DOCS-349 deploys regresses ~120 currently-working links
into 404s on coder.com | Clear DO-NOT-MERGE banner; tracked as blocker
in Linear. |
| Relative path computed incorrectly (off-by-one `..`) | Verified all
114 newly-relative non-md/non-image paths resolve to existing files in
the repo (only exception is the pre-existing dead `nix` link above). |
| Line anchors stripped during conversion | Preserved by the
substitution regex; verified `#L<n>-L<m>` cases in `airgap.md` and
`speed-up-templates.md`. |
| Future code reorgs change file locations | Relative links will start
pointing to nothing. Same failure mode as absolute links pointing to
renamed files; can be caught with a future link-checker job. |
## Validation
```
$ grep -rE 'github\.com/coder/coder/(blob|tree)/main' docs --include="*.md" | wc -l
0
$ git diff --stat origin/main | tail -1
39 files changed, 118 insertions(+), 118 deletions(-)
```
114 newly-relative paths verified to resolve to existing repo files
(Python `os.path.exists` check on each computed target).
<details>
<summary>Decision log + planning context</summary>
**Why relative over `(blob|tree)/{{currentDocsVersion}}/...`
templating**: relative paths require zero markdown-system support and
zero upstream churn beyond this one PR. Templating would require a
preprocessor on `coder.com` side AND a convention upstream authors have
to remember; relative paths just work in a plain editor and
`github.com`'s own renderer too.
**Why `./` prefix on same-directory targets**: makes the conversion
grep-able later (`grep -E '\((\.\./|\./)'`).
**Why preserve `#L<n>-L<m>` anchors verbatim**: the anchor is meaningful
to the linked file's content, not to the URL form; keeping it as-is
preserves authorial intent. If the file later changes such that the line
range drifts, that's a different problem the SHA-pin audit
([DOCS-352](https://linear.app/codercom/issue/DOCS-352)) will surface.
</details>
---
*Generated by Coder Agents on @nickvigilante's behalf.*
## Drive-by external link fix folded in
`docs/about/contributing/CONTRIBUTING.md:296` cited
`https://reflectoring.io/meaningful-commit-messages/` which is returning
HTTP 503 (the host appears to be down site-wide right now). `check-docs`
Linkspector flagged it after the rebase. Replaced with
`https://cbea.ms/git-commit/` (Chris Beams' canonical "If applied, this
commit will..." article, confirmed 200), which is the original source of
the rule the prose recites anyway.
Subdomain app routing derived the app identity from
httpapi.RequestHost, which returned the client-supplied
X-Forwarded-Host header verbatim. No middleware validated or stripped
that header, so a request from an untrusted peer could forge it. Since
the application_connect cookie is scoped to the wildcard apps domain,
JavaScript in a share=authenticated app could fetch() with a forged
X-Forwarded-Host pointing at a victim's owner-only app; coderd routed
and authorized the request as the victim and returned the private app
response same-origin to the attacker.
Replace RequestHost with httpmw.EffectiveHost, which honors
X-Forwarded-Host only when the original socket peer is a configured
trusted origin, otherwise falling back to the received Host header.
This ties host trust to the same RealIPConfig model already used for
X-Forwarded-For and -Proto. Wire it into HandleSubdomain for both
coderd and wsproxy, and log both the effective host and the raw
received_host.
Add coverage: EffectiveHost unit tests assert the trust decision uses
the socket peer rather than the spoofable forwarded client IP, and a
HandleSubdomain test confirms a forged X-Forwarded-Host from an
untrusted peer never reaches token resolution.
Refs: https://linear.app/codercom/issue/PLAT-259
I noticed that our docs mention the possibility of using the
Tailscale-managed DERP server fleet.
https://github.com/coder/coder/pull/15901 changed the phrasing from
> However, Tailscale has graciously allowed us to use
to
> However, our Wireguard integration through Tailscale has graciously
allowed us to use
This change alters the original meaning of the sentence. AFAIK, the
original meant that we contacted Tailscale directly and asked if it
would be ok for our customers to use the Tailscale-managed DERP server
fleet, and Tailscale graciously agreed. The new phrasing conveys
something different. This PR reverts the phrasing to the original.
---------
Co-authored-by: david-fraley <67079030+david-fraley@users.noreply.github.com>
Fixes docs troubleshooting language around low MTU. In fact, we see
conenctions hanging rather than just showing low performance, since
packets are dropped rather than fragmented.
---------
Co-authored-by: Edward Angert <EdwardAngert@users.noreply.github.com>
Co-authored-by: EdwardAngert <17991901+EdwardAngert@users.noreply.github.com>
> We do not use Tailscale (product) but instead import Tailscale OSS
libraries which has some nice ways of handling Wireguard. We also use
Tailscale's logo in our architecture, but calling it only `Tailscale`
seems to throw people off when they're considering Coder and how it
works.
I've left it wherever it seems to make sense (such as when we talk about
[DERP](https://coder.com/docs/admin/networking#relayed-connections)),
and sprinkled some `Wireguard` and `websocket/HTTPS` where I could
Nick Vigilante