When using a basepath of /chronograf, the app would present a
never-ending spinner when visiting the root route. This was because the
prefixingRedirector middleware which is responsible for appending the
basepath to redirects from downstream http.Handlers thought that the
prefix was already appended since it saw `/chronograf/v1`. In reality,
it should have produced a location like `/chronograf/chronograf/v1`.
The solution was to look beyond the first instance of a prefix and check
for the presence of another prefix to detect if a prefix was already
applied by a downstream handler.
The Basepath option should be applied in anything that will be consumed
by the React application. This is because from its perspective, the
proxy sitting between it and the backend wants those prefixes regardless
of what it does with them before handing the request back to the
Chronograf backend. Consequently, there's situations in the backend
where we need to have the `opts.Basepath` or the `basepath` that we
alter when `opts.PrefixRoutes` is set. The `basepath` is strictly for
altering routing decisions made by the backend.
There's subtle places where routes are supplied to the frontend that
need to always have the `opts.Basepath` set as well. Another commit
addressed the "Location" header of Redirects, for example.
The router that we use has a feature that will automatically redirect
routes in certain situations where it feels a trailing slash would be
appropriate. Because the underlying router is totally unaware of
upstream prefixing activity, the "Location" that it sends clients to is
incorrect because it doesn't have the prefix.
This introduces a middleware that catches any downstream 3XX class
responses and replaces the Location header with the prefixed version of
it, plus a trailing slash. It does this only when the prefix has not
been applied already by some downstream middleware.
This adds the status code to the response log message to make it easier
to diagnose issues. It also replaces the placeholder "Success" message
with the decoded value of the HTTP Status, resulting in messages like:
INFO[0041] Response: Temporary Redirect code=307
...and so on. Both easily consumable by humans and machines.
Basepath was previously not working here because the strings constructed
via concatenation had a trailing slash at the end:
Before:
rootPath => "/someprefix/chronograf/v1/"
After:
rootPath => "/someprefix/chronograf/v1"
The julienschmidt/httprouter that the bouk/httprouter is based on has
support for ignoring trailing slashes, which is behavior that we want.
However, routing decisions involving this rootPath string were being
made by a `strings.HasPrefix` function. This conditional seeks to
apply the token middleware only in cases where routes _under_
`/chronograf/v1` are accessed (e.g. `/chronograf/v1/sources`). In cases
where the paths were effectively equal, this conditional accidentally
worked because the string `/chronograf/v1` does not have the prefix
`/chronograf/v1/`. When this was corrected to use `path.Join`, this case
became true and caused the token middleware to be applied.
`path.Join` is the correct way to construct paths, since this prevents
issues where a fragment like `/foo/` is concatenated with a fragment
like `/bar/quux/` to yield the string `/foo//bar/quux/`.
Given that continuing to use concatenation is no longer an option, the
solution is to compare the lengths of the strings to ensure that the
path under comparison is longer than the prefix it's being tested
against. This guarantees that the subject path is a route underneath the
`/chronograf/v1` route.
Updated the logout link in the UI to use a link provided by the
/chronograf/v1/ endpoint. We also replaced many instances of string
concatenation of URL paths with path.Join, which better handles cases
where prefixed and suffixed "/" characters may be present in provided
basepaths. We also refactored how Basepath was being prefixed when using
Auth. Documentation was also updated to warn users that basepaths should
be applied to the OAuth callback link when configuring OAuth with their
provider.
Timothy J. Raymond
Kent Wang
Jared Scheib
Jared Scheib
Tim Raymond
Hunter Trujillo
Regan Kuchan
Chris Goller
Andrew Watkins
Luke Morris
Jade McGough