While building a layer4 app for Caddy, I discovered that we need the
ability to fill a request's context just like the HTTP server does,
hence this exported function PrepareRequest().
The fix that was initially put forth in #2971 was good, but only for
up to one layer of nesting. The real problem was that we forgot to
increment nesting when already inside a block if we saw another open
curly brace that opens another block (dispenser.go L157-158).
The new 'handle' directive allows HTTP Caddyfiles to be designed more
like nginx location blocks if the user prefers. Inside a handle block,
directives are still ordered just like they are outside of them, but
handler blocks at a given level of nesting are mutually exclusive.
This work benefitted from some refactoring and cleanup.
This splits automatic HTTPS into two phases. The first provisions the
route matchers and uses them to build the domain set and configure
auto HTTP->HTTPS redirects. This happens before the rest of the
provisioning does.
The second phase takes place at the beginning of the app start. It
attaches pointers to the tls app to each server, and begins certificate
management for the domains that were found in the first phase.
Previously, all matchers in a route would be evaluated before any
handlers were executed, and a composite route of the matching routes
would be created. This made rewrites especially tricky, since the only
way to defer later matchers' evaluation was to wrap them in a subroute,
or to invoke a "rehandle" which often caused bugs.
Instead, this new sequential design evaluates each route's matchers then
its handlers in lock-step; matcher-handlers-matcher-handlers...
If the first matching route consists of a rewrite, then the second route
will be evaluated against the rewritten request, rather than the original
one, and so on.
This should do away with any need for rehandling.
I've also taken this opportunity to avoid adding new values to the
request context in the handler chain, as this creates a copy of the
Request struct, which may possibly lead to bugs like it has in the past
(see PR #1542, PR #1481, and maybe issue #2463). We now add all the
expected context values in the top-level handler at the server, then
any new values can be added to the variable table via the VarsCtxKey
context key, or just the GetVar/SetVar functions. In particular, we are
using this facility to convey dial information in the reverse proxy.
Had to be careful in one place as the middleware compilation logic has
changed, and moved a bit. We no longer compile a middleware chain per-
request; instead, we can compile it at provision-time, and defer only the
evaluation of matchers to request-time, which should slightly improve
performance. Doing this, however, we take advantage of multiple function
closures, and we also changed the use of HandlerFunc (function pointer)
to Handler (interface)... this led to a situation where, if we aren't
careful, allows one request routed a certain way to permanently change
the "next" handler for all/most other requests! We avoid this by making
a copy of the interface value (which is a lightweight pointer copy) and
using exclusively that within our wrapped handlers. This way, the
original stack frame is preserved in a "read-only" fashion. The comments
in the code describe this phenomenon.
This may very well be a breaking change for some configurations, however
I do not expect it to impact many people. I will make it clear in the
release notes that this change has occurred.
This commit goes a long way toward making automated documentation of
Caddy config and Caddy modules possible. It's a broad, sweeping change,
but mostly internal. It allows us to automatically generate docs for all
Caddy modules (including future third-party ones) and make them viewable
on a web page; it also doubles as godoc comments.
As such, this commit makes significant progress in migrating the docs
from our temporary wiki page toward our new website which is still under
construction.
With this change, all host modules will use ctx.LoadModule() and pass in
both the struct pointer and the field name as a string. This allows the
reflect package to read the struct tag from that field so that it can
get the necessary information like the module namespace and the inline
key.
This has the nice side-effect of unifying the code and documentation. It
also simplifies module loading, and handles several variations on field
types for raw module fields (i.e. variations on json.RawMessage, such as
arrays and maps).
I also renamed ModuleInfo.Name -> ModuleInfo.ID, to make it clear that
the ID is the "full name" which includes both the module namespace and
the name. This clarity is helpful when describing module hierarchy.
As of this change, Caddy modules are no longer an experimental design.
I think the architecture is good enough to go forward.
Use piles from which to draw config values.
Module values can return their name, so now we can do two-way mapping
from value to name and name to value; whereas before we could only map
name to value. This was problematic with the Caddyfile adapter since
it receives values and needs to know the name to put in the config.
Along with several other changes, such as renaming caddyhttp.ServerRoute
to caddyhttp.Route, exporting some types that were not exported before,
and tweaking the caddytls TLS values to be more consistent.
Notably, we also now disable automatic cert management for names which
already have a cert (manually) loaded into the cache. These names no
longer need to be specified in the "skip_certificates" field of the
automatic HTTPS config, because they will be skipped automatically.
Differentiating middleware and responders has one benefit, namely that
it's clear which module provides the response, but even then it's not
a great advantage. Linear handler config makes a little more sense,
giving greater flexibility and simplifying the core a bit, even though
it's slightly awkward that handlers which are responders may not use
the 'next' handler that is passed in at all.
