From 95ed603de79c66ff76bfe7e42986a2fc8c7a1fa4 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Mon, 23 Dec 2019 12:45:35 -0700
Subject: Improve godocs all around

These will be used in the new automated documentation system
---
 modules/caddyhttp/caddyauth/basicauth.go          | 19 +++--
 modules/caddyhttp/caddyauth/caddyauth.go          |  3 +
 modules/caddyhttp/caddyauth/hashes.go             | 14 +++-
 modules/caddyhttp/encode/brotli/brotli.go         |  4 +-
 modules/caddyhttp/encode/encode.go                | 12 ++--
 modules/caddyhttp/fileserver/browse.go            |  1 +
 modules/caddyhttp/fileserver/matcher.go           | 22 +++---
 modules/caddyhttp/fileserver/staticfiles.go       | 29 ++++++--
 modules/caddyhttp/headers/headers.go              | 54 ++++++++++----
 modules/caddyhttp/httpcache/httpcache.go          | 30 ++++++--
 modules/caddyhttp/matchers.go                     |  4 +-
 modules/caddyhttp/requestbody/requestbody.go      |  1 +
 modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go |  2 +-
 modules/caddyhttp/reverseproxy/healthchecks.go    | 72 +++++++++++++++----
 modules/caddyhttp/reverseproxy/hosts.go           | 18 ++++-
 modules/caddyhttp/reverseproxy/ntlm.go            |  4 ++
 modules/caddyhttp/reverseproxy/reverseproxy.go    | 87 +++++++++++++++++++----
 modules/caddyhttp/rewrite/rewrite.go              | 33 +++++++--
 modules/caddyhttp/server.go                       | 22 +++++-
 modules/caddyhttp/starlarkmw/example/caddy.json   |  2 +-
 modules/caddyhttp/staticerror.go                  | 12 +++-
 modules/caddyhttp/staticresp.go                   | 17 +++--
 modules/caddyhttp/subroute.go                     |  6 +-
 modules/caddyhttp/templates/caddyfile.go          |  2 +-
 modules/caddyhttp/vars.go                         |  3 +-
 25 files changed, 381 insertions(+), 92 deletions(-)

(limited to 'modules/caddyhttp')

diff --git a/modules/caddyhttp/caddyauth/basicauth.go b/modules/caddyhttp/caddyauth/basicauth.go
index 8aa44f1..74aa407 100644
--- a/modules/caddyhttp/caddyauth/basicauth.go
+++ b/modules/caddyhttp/caddyauth/basicauth.go
@@ -28,9 +28,14 @@ func init() {
 
 // HTTPBasicAuth facilitates HTTP basic authentication.
 type HTTPBasicAuth struct {
-	HashRaw     json.RawMessage `json:"hash,omitempty" caddy:"namespace=http.authentication.hashes inline_key=algorithm"`
-	AccountList []Account       `json:"accounts,omitempty"`
-	Realm       string          `json:"realm,omitempty"`
+	// The algorithm with which the passwords are hashed. Default: bcrypt
+	HashRaw json.RawMessage `json:"hash,omitempty" caddy:"namespace=http.authentication.hashes inline_key=algorithm"`
+
+	// The list of accounts to authenticate.
+	AccountList []Account `json:"accounts,omitempty"`
+
+	// The name of the realm. Default: restricted
+	Realm string `json:"realm,omitempty"`
 
 	Accounts map[string]Account `json:"-"`
 	Hash     Comparer           `json:"-"`
@@ -125,9 +130,15 @@ type Comparer interface {
 
 // Account contains a username, password, and salt (if applicable).
 type Account struct {
+	// A user's username.
 	Username string `json:"username"`
+
+	// The user's hashed password, base64-encoded.
 	Password []byte `json:"password"`
-	Salt     []byte `json:"salt,omitempty"` // for algorithms where external salt is needed
+
+	// The user's password salt, base64-encoded; for
+	// algorithms where external salt is needed.
+	Salt []byte `json:"salt,omitempty"`
 }
 
 // Interface guards
diff --git a/modules/caddyhttp/caddyauth/caddyauth.go b/modules/caddyhttp/caddyauth/caddyauth.go
index c814caf..aefeec5 100644
--- a/modules/caddyhttp/caddyauth/caddyauth.go
+++ b/modules/caddyhttp/caddyauth/caddyauth.go
@@ -28,7 +28,10 @@ func init() {
 }
 
 // Authentication is a middleware which provides user authentication.
+// Rejects requests with HTTP 401 if the request is not authenticated.
 type Authentication struct {
+	// A set of authentication providers. If none are specified,
+	// all requests will always be unauthenticated.
 	ProvidersRaw caddy.ModuleMap `json:"providers,omitempty" caddy:"namespace=http.authentication.providers"`
 
 	Providers map[string]Authenticator `json:"-"`
diff --git a/modules/caddyhttp/caddyauth/hashes.go b/modules/caddyhttp/caddyauth/hashes.go
index 3ca5116..5a3173e 100644
--- a/modules/caddyhttp/caddyauth/hashes.go
+++ b/modules/caddyhttp/caddyauth/hashes.go
@@ -52,9 +52,17 @@ func (BcryptHash) Compare(hashed, plaintext, _ []byte) (bool, error) {
 
 // ScryptHash implements the scrypt KDF as a hash.
 type ScryptHash struct {
-	N         int `json:"N,omitempty"`
-	R         int `json:"r,omitempty"`
-	P         int `json:"p,omitempty"`
+	// scrypt's N parameter. If unset or 0, a safe default is used.
+	N int `json:"N,omitempty"`
+
+	// scrypt's r parameter. If unset or 0, a safe default is used.
+	R int `json:"r,omitempty"`
+
+	// scrypt's p parameter. If unset or 0, a safe default is used.
+	P int `json:"p,omitempty"`
+
+	// scrypt's key length parameter (in bytes). If unset or 0, a
+	// safe default is used.
 	KeyLength int `json:"key_length,omitempty"`
 }
 
diff --git a/modules/caddyhttp/encode/brotli/brotli.go b/modules/caddyhttp/encode/brotli/brotli.go
index 52bb205..fababd3 100644
--- a/modules/caddyhttp/encode/brotli/brotli.go
+++ b/modules/caddyhttp/encode/brotli/brotli.go
@@ -29,7 +29,9 @@ func init() {
 }
 
 // Brotli can create brotli encoders. Note that brotli
-// is not known for great encoding performance.
+// is not known for great encoding performance, and
+// its use during requests is discouraged; instead,
+// pre-compress the content instead.
 type Brotli struct {
 	Quality *int `json:"quality,omitempty"`
 }
diff --git a/modules/caddyhttp/encode/encode.go b/modules/caddyhttp/encode/encode.go
index c68f507..c3a1c23 100644
--- a/modules/caddyhttp/encode/encode.go
+++ b/modules/caddyhttp/encode/encode.go
@@ -39,9 +39,15 @@ func init() {
 
 // Encode is a middleware which can encode responses.
 type Encode struct {
+	// Selection of compression algorithms to choose from. The best one
+	// will be chosen based on the client's Accept-Encoding header.
 	EncodingsRaw caddy.ModuleMap `json:"encodings,omitempty" caddy:"namespace=http.encoders"`
-	Prefer       []string        `json:"prefer,omitempty"`
-	MinLength    int             `json:"minimum_length,omitempty"`
+
+	// If the client has no strong preference, choose this encoding. TODO: Not yet implemented
+	// Prefer    []string `json:"prefer,omitempty"`
+
+	// Only encode responses that are at least this many bytes long.
+	MinLength int `json:"minimum_length,omitempty"`
 
 	writerPools map[string]*sync.Pool // TODO: these pools do not get reused through config reloads...
 }
@@ -66,11 +72,9 @@ func (enc *Encode) Provision(ctx caddy.Context) error {
 			return fmt.Errorf("adding encoding %s: %v", modName, err)
 		}
 	}
-
 	if enc.MinLength == 0 {
 		enc.MinLength = defaultMinLength
 	}
-
 	return nil
 }
 
diff --git a/modules/caddyhttp/fileserver/browse.go b/modules/caddyhttp/fileserver/browse.go
index 48f2cc7..aa8372e 100644
--- a/modules/caddyhttp/fileserver/browse.go
+++ b/modules/caddyhttp/fileserver/browse.go
@@ -29,6 +29,7 @@ import (
 
 // Browse configures directory browsing.
 type Browse struct {
+	// Use this template file instead of the default browse template.
 	TemplateFile string `json:"template_file,omitempty"`
 
 	template *template.Template
diff --git a/modules/caddyhttp/fileserver/matcher.go b/modules/caddyhttp/fileserver/matcher.go
index 13cb60a..5ca97f2 100644
--- a/modules/caddyhttp/fileserver/matcher.go
+++ b/modules/caddyhttp/fileserver/matcher.go
@@ -46,7 +46,13 @@ type MatchFile struct {
 	// placeholders.
 	TryFiles []string `json:"try_files,omitempty"`
 
-	// How to choose a file in TryFiles.
+	// How to choose a file in TryFiles. Can be:
+	//
+	// - first_exist
+	// - smallest_size
+	// - largest_size
+	// - most_recently_modified
+	//
 	// Default is first_exist.
 	TryPolicy string `json:"try_policy,omitempty"`
 }
@@ -64,7 +70,7 @@ func (MatchFile) CaddyModule() caddy.ModuleInfo {
 //     file {
 //         root <path>
 //         try_files <files...>
-//         try_policy first_exist|smallest_size|largest_size|most_recent_modified
+//         try_policy first_exist|smallest_size|largest_size|most_recently_modified
 //     }
 //
 func (m *MatchFile) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
@@ -107,7 +113,7 @@ func (m MatchFile) Validate() error {
 		tryPolicyFirstExist,
 		tryPolicyLargestSize,
 		tryPolicySmallestSize,
-		tryPolicyMostRecentMod:
+		tryPolicyMostRecentlyMod:
 	default:
 		return fmt.Errorf("unknown try policy %s", m.TryPolicy)
 	}
@@ -187,7 +193,7 @@ func (m MatchFile) selectFile(r *http.Request) (rel, abs string, matched bool) {
 		}
 		return smallestSuffix, smallestFilename, true
 
-	case tryPolicyMostRecentMod:
+	case tryPolicyMostRecentlyMod:
 		var recentDate time.Time
 		var recentFilename string
 		var recentSuffix string
@@ -238,10 +244,10 @@ func strictFileExists(file string) bool {
 }
 
 const (
-	tryPolicyFirstExist    = "first_exist"
-	tryPolicyLargestSize   = "largest_size"
-	tryPolicySmallestSize  = "smallest_size"
-	tryPolicyMostRecentMod = "most_recent_modified"
+	tryPolicyFirstExist      = "first_exist"
+	tryPolicyLargestSize     = "largest_size"
+	tryPolicySmallestSize    = "smallest_size"
+	tryPolicyMostRecentlyMod = "most_recently_modified"
 )
 
 // Interface guards
diff --git a/modules/caddyhttp/fileserver/staticfiles.go b/modules/caddyhttp/fileserver/staticfiles.go
index a9e6e1c..f2722ba 100644
--- a/modules/caddyhttp/fileserver/staticfiles.go
+++ b/modules/caddyhttp/fileserver/staticfiles.go
@@ -42,12 +42,29 @@ func init() {
 
 // FileServer implements a static file server responder for Caddy.
 type FileServer struct {
-	Root          string   `json:"root,omitempty"` // default is current directory
-	Hide          []string `json:"hide,omitempty"`
-	IndexNames    []string `json:"index_names,omitempty"`
-	Browse        *Browse  `json:"browse,omitempty"`
-	CanonicalURIs *bool    `json:"canonical_uris,omitempty"`
-	PassThru      bool     `json:"pass_thru,omitempty"` // if 404, call next handler instead
+	// The path to the root of the site. Default is `{http.vars.root}` if set,
+	// or current working directory otherwise.
+	Root string `json:"root,omitempty"`
+
+	// A list of files or folders to hide; the file server will pretend as if
+	// they don't exist. Accepts globular patterns like "*.hidden" or "/foo/*/bar".
+	Hide []string `json:"hide,omitempty"`
+
+	// The names of files to try as index files if a folder is requested.
+	IndexNames []string `json:"index_names,omitempty"`
+
+	// Enables file listings if a directory was requested and no index
+	// file is present.
+	Browse *Browse `json:"browse,omitempty"`
+
+	// Use redirects to enforce trailing slashes for directories, or to
+	// remove trailing slash from URIs for files. Default is true.
+	CanonicalURIs *bool `json:"canonical_uris,omitempty"`
+
+	// If pass-thru mode is enabled and a requested file is not found,
+	// it will invoke the next handler in the chain instead of returning
+	// a 404 error. By default, this is false (disabled).
+	PassThru bool `json:"pass_thru,omitempty"`
 }
 
 // CaddyModule returns the Caddy module information.
diff --git a/modules/caddyhttp/headers/headers.go b/modules/caddyhttp/headers/headers.go
index f53e859..ad6c08b 100644
--- a/modules/caddyhttp/headers/headers.go
+++ b/modules/caddyhttp/headers/headers.go
@@ -28,7 +28,18 @@ func init() {
 	caddy.RegisterModule(Handler{})
 }
 
-// Handler is a middleware which can mutate HTTP headers.
+// Handler is a middleware which modifies request and response headers.
+//
+// Changes to headers are applied immediately, except for the response
+// headers when Deferred is true or when Required is set. In those cases,
+// the changes are applied when the headers are written to the response.
+// Note that deferred changes do not take effect if an error occurs later
+// in the middleware chain.
+//
+// Properties in this module accept placeholders.
+//
+// Response header operations can be conditioned upon response status code
+// and/or other header values.
 type Handler struct {
 	Request  *HeaderOps     `json:"request,omitempty"`
 	Response *RespHeaderOps `json:"response,omitempty"`
@@ -99,12 +110,18 @@ func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhtt
 	return next.ServeHTTP(w, r)
 }
 
-// HeaderOps defines some operations to
-// perform on HTTP headers.
+// HeaderOps defines manipulations for HTTP headers.
 type HeaderOps struct {
-	Add     http.Header              `json:"add,omitempty"`
-	Set     http.Header              `json:"set,omitempty"`
-	Delete  []string                 `json:"delete,omitempty"`
+	// Adds HTTP headers; does not replace any existing header fields.
+	Add http.Header `json:"add,omitempty"`
+
+	// Sets HTTP headers; replaces existing header fields.
+	Set http.Header `json:"set,omitempty"`
+
+	// Names of HTTP header fields to delete.
+	Delete []string `json:"delete,omitempty"`
+
+	// Performs substring replacements of HTTP headers in-situ.
 	Replace map[string][]Replacement `json:"replace,omitempty"`
 }
 
@@ -135,22 +152,33 @@ func (ops HeaderOps) validate() error {
 }
 
 // Replacement describes a string replacement,
-// either a simple and fast sugbstring search
+// either a simple and fast substring search
 // or a slower but more powerful regex search.
 type Replacement struct {
-	Search       string `json:"search,omitempty"`
+	// The substring to search for.
+	Search string `json:"search,omitempty"`
+
+	// The regular expression to search with.
 	SearchRegexp string `json:"search_regexp,omitempty"`
-	Replace      string `json:"replace,omitempty"`
+
+	// The string with which to replace matches.
+	Replace string `json:"replace,omitempty"`
 
 	re *regexp.Regexp
 }
 
-// RespHeaderOps is like HeaderOps, but
-// optionally deferred until response time.
+// RespHeaderOps defines manipulations for response headers.
 type RespHeaderOps struct {
 	*HeaderOps
-	Require  *caddyhttp.ResponseMatcher `json:"require,omitempty"`
-	Deferred bool                       `json:"deferred,omitempty"`
+
+	// If set, header operations will be deferred until
+	// they are written out and only performed if the
+	// response matches these criteria.
+	Require *caddyhttp.ResponseMatcher `json:"require,omitempty"`
+
+	// If true, header operations will be deferred until
+	// they are written out. Superceded if Require is set.
+	Deferred bool `json:"deferred,omitempty"`
 }
 
 // ApplyTo applies ops to hdr using repl.
diff --git a/modules/caddyhttp/httpcache/httpcache.go b/modules/caddyhttp/httpcache/httpcache.go
index 81f5816..f8bdde8 100644
--- a/modules/caddyhttp/httpcache/httpcache.go
+++ b/modules/caddyhttp/httpcache/httpcache.go
@@ -33,11 +33,33 @@ func init() {
 }
 
 // Cache implements a simple distributed cache.
+//
+// NOTE: This module is a work-in-progress. It is
+// not finished and is NOT ready for production use.
+// [We need your help to finish it! Please volunteer
+// in this issue.](https://github.com/caddyserver/caddy/issues/2820)
+// Until it is finished, this module is subject to
+// breaking changes.
+//
+// Caches only GET and HEAD requests. Honors the Cache-Control: no-cache header.
+//
+// Still TODO:
+//
+// - Eviction policies and API
+// - Use single cache per-process
+// - Preserve cache through config reloads
+// - More control over what gets cached
 type Cache struct {
-	Self    string   `json:"self,omitempty"`
-	Peers   []string `json:"peers,omitempty"`
-	MaxSize int64    `json:"max_size,omitempty"`
-	group   *groupcache.Group
+	// The network address of this cache instance; required.
+	Self string `json:"self,omitempty"`
+
+	// A list of network addresses of cache instances in the group.
+	Peers []string `json:"peers,omitempty"`
+
+	// Maximum size of the cache, in bytes. Default is 512 MB.
+	MaxSize int64 `json:"max_size,omitempty"`
+
+	group *groupcache.Group
 }
 
 // CaddyModule returns the Caddy module information.
diff --git a/modules/caddyhttp/matchers.go b/modules/caddyhttp/matchers.go
index 6d1728d..00f273e 100644
--- a/modules/caddyhttp/matchers.go
+++ b/modules/caddyhttp/matchers.go
@@ -695,8 +695,8 @@ func (mre *MatchRegexp) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 	return nil
 }
 
-// ResponseMatcher is a type which can determine if a given response
-// status code and its headers match some criteria.
+// ResponseMatcher is a type which can determine if an
+// HTTP response matches some criteria.
 type ResponseMatcher struct {
 	// If set, one of these status codes would be required.
 	// A one-digit status can be used to represent all codes
diff --git a/modules/caddyhttp/requestbody/requestbody.go b/modules/caddyhttp/requestbody/requestbody.go
index dd3f256..dcebd8c 100644
--- a/modules/caddyhttp/requestbody/requestbody.go
+++ b/modules/caddyhttp/requestbody/requestbody.go
@@ -27,6 +27,7 @@ func init() {
 
 // RequestBody is a middleware for manipulating the request body.
 type RequestBody struct {
+	// The maximum number of bytes to allow reading from the body by a later handler.
 	MaxSize int64 `json:"max_size,omitempty"`
 }
 
diff --git a/modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go b/modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go
index aff9a6e..f3f979d 100644
--- a/modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go
+++ b/modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go
@@ -57,7 +57,7 @@ type Transport struct {
 	// that 404's if the fastcgi path info is not found.
 	SplitPath string `json:"split_path,omitempty"`
 
-	// Extra environment variables
+	// Extra environment variables.
 	EnvVars map[string]string `json:"env,omitempty"`
 
 	// The duration used to set a deadline when connecting to an upstream.
diff --git a/modules/caddyhttp/reverseproxy/healthchecks.go b/modules/caddyhttp/reverseproxy/healthchecks.go
index a64d845..76ee945 100644
--- a/modules/caddyhttp/reverseproxy/healthchecks.go
+++ b/modules/caddyhttp/reverseproxy/healthchecks.go
@@ -31,9 +31,16 @@ import (
 	"go.uber.org/zap"
 )
 
-// HealthChecks holds configuration related to health checking.
+// HealthChecks configures active and passive health checks.
 type HealthChecks struct {
-	Active  *ActiveHealthChecks  `json:"active,omitempty"`
+	// Active health checks run in the background on a timer. To
+	// minimally enable active health checks, set either path or
+	// port (or both).
+	Active *ActiveHealthChecks `json:"active,omitempty"`
+
+	// Passive health checks monitor proxied requests for errors or timeouts.
+	// To minimally enable passive health checks, specify at least an empty
+	// config object.
 	Passive *PassiveHealthChecks `json:"passive,omitempty"`
 }
 
@@ -41,14 +48,33 @@ type HealthChecks struct {
 // health checks (that is, health checks which occur in a
 // background goroutine independently).
 type ActiveHealthChecks struct {
-	Path         string         `json:"path,omitempty"`
-	Port         int            `json:"port,omitempty"`
-	Headers      http.Header    `json:"headers,omitempty"`
-	Interval     caddy.Duration `json:"interval,omitempty"`
-	Timeout      caddy.Duration `json:"timeout,omitempty"`
-	MaxSize      int64          `json:"max_size,omitempty"`
-	ExpectStatus int            `json:"expect_status,omitempty"`
-	ExpectBody   string         `json:"expect_body,omitempty"`
+	// The URI path to use for health checks.
+	Path string `json:"path,omitempty"`
+
+	// The port to use (if different from the upstream's dial
+	// address) for health checks.
+	Port int `json:"port,omitempty"`
+
+	// HTTP headers to set on health check requests.
+	Headers http.Header `json:"headers,omitempty"`
+
+	// How frequently to perform active health checks (default 30s).
+	Interval caddy.Duration `json:"interval,omitempty"`
+
+	// How long to wait for a response from a backend before
+	// considering it unhealthy (default 5s).
+	Timeout caddy.Duration `json:"timeout,omitempty"`
+
+	// The maximum response body to download from the backend
+	// during a health check.
+	MaxSize int64 `json:"max_size,omitempty"`
+
+	// The HTTP status code to expect from a healthy backend.
+	ExpectStatus int `json:"expect_status,omitempty"`
+
+	// A regular expression against which to match the response
+	// body of a healthy backend.
+	ExpectBody string `json:"expect_body,omitempty"`
 
 	stopChan   chan struct{}
 	httpClient *http.Client
@@ -60,11 +86,27 @@ type ActiveHealthChecks struct {
 // health checks (that is, health checks which occur during
 // the normal flow of request proxying).
 type PassiveHealthChecks struct {
-	MaxFails              int            `json:"max_fails,omitempty"`
-	FailDuration          caddy.Duration `json:"fail_duration,omitempty"`
-	UnhealthyRequestCount int            `json:"unhealthy_request_count,omitempty"`
-	UnhealthyStatus       []int          `json:"unhealthy_status,omitempty"`
-	UnhealthyLatency      caddy.Duration `json:"unhealthy_latency,omitempty"`
+	// How long to remember a failed request to a backend. A duration > 0
+	// enables passive health checking. Default is 0.
+	FailDuration caddy.Duration `json:"fail_duration,omitempty"`
+
+	// The number of failed requests within the FailDuration window to
+	// consider a backend as "down". Must be >= 1; default is 1. Requires
+	// that FailDuration be > 0.
+	MaxFails int `json:"max_fails,omitempty"`
+
+	// Limits the number of simultaneous requests to a backend by
+	// marking the backend as "down" if it has this many concurrent
+	// requests or more.
+	UnhealthyRequestCount int `json:"unhealthy_request_count,omitempty"`
+
+	// Count the request as failed if the response comes back with
+	// one of these status codes.
+	UnhealthyStatus []int `json:"unhealthy_status,omitempty"`
+
+	// Count the request as failed if the response takes at least this
+	// long to receive.
+	UnhealthyLatency caddy.Duration `json:"unhealthy_latency,omitempty"`
 
 	logger *zap.Logger
 }
diff --git a/modules/caddyhttp/reverseproxy/hosts.go b/modules/caddyhttp/reverseproxy/hosts.go
index 8bad7c2..e7c61fb 100644
--- a/modules/caddyhttp/reverseproxy/hosts.go
+++ b/modules/caddyhttp/reverseproxy/hosts.go
@@ -61,8 +61,22 @@ type UpstreamPool []*Upstream
 type Upstream struct {
 	Host `json:"-"`
 
-	Dial        string `json:"dial,omitempty"`
-	MaxRequests int    `json:"max_requests,omitempty"`
+	// The [network address](/docs/json/apps/http/#servers/listen)
+	// to dial to connect to the upstream. Must represent precisely
+	// one socket (i.e. no port ranges). A valid network address
+	// either has a host and port, or is a unix socket address.
+	//
+	// Placeholders may be used to make the upstream dynamic, but be
+	// aware of the health check implications of this: a single
+	// upstream that represents numerous (perhaps arbitrary) backends
+	// can be considered down if one or enough of the arbitrary
+	// backends is down. Also be aware of open proxy vulnerabilities.
+	Dial string `json:"dial,omitempty"`
+
+	// The maximum number of simultaneous requests to allow to
+	// this upstream. If set, overrides the global passive health
+	// check UnhealthyRequestCount value.
+	MaxRequests int `json:"max_requests,omitempty"`
 
 	// TODO: This could be really useful, to bind requests
 	// with certain properties to specific backends
diff --git a/modules/caddyhttp/reverseproxy/ntlm.go b/modules/caddyhttp/reverseproxy/ntlm.go
index ea2bb85..be4330f 100644
--- a/modules/caddyhttp/reverseproxy/ntlm.go
+++ b/modules/caddyhttp/reverseproxy/ntlm.go
@@ -46,6 +46,10 @@ func init() {
 //
 // This transport also forces HTTP/1.1 and Keep-Alives in order
 // for NTLM to succeed.
+//
+// It is basically the same thing as
+// [nginx's paid ntlm directive](https://nginx.org/en/docs/http/ngx_http_upstream_module.html#ntlm)
+// (but is free in Caddy!).
 type NTLMTransport struct {
 	*HTTPTransport
 
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index d353dc1..24389b2 100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -41,15 +41,56 @@ func init() {
 }
 
 // Handler implements a highly configurable and production-ready reverse proxy.
+// Upon proxying, this module sets the following placeholders (which can be used
+// both within and after this handler):
+//
+//  {http.reverse_proxy.upstream.address}
+//		The full address to the upstream as given in the config
+//	{http.reverse_proxy.upstream.hostport}
+//		The host:port of the upstream
+//	{http.reverse_proxy.upstream.host}
+//		The host of the upstream
+//	{http.reverse_proxy.upstream.port}
+//		The port of the upstream
+//	{http.reverse_proxy.upstream.requests}
+//		The approximate current number of requests to the upstream
+//	{http.reverse_proxy.upstream.max_requests}
+//		The maximum approximate number of requests allowed to the upstream
+//	{http.reverse_proxy.upstream.fails}
+//		The number of recent failed requests to the upstream
+//
 type Handler struct {
-	TransportRaw   json.RawMessage  `json:"transport,omitempty" caddy:"namespace=http.reverse_proxy.transport inline_key=protocol"`
-	CBRaw          json.RawMessage  `json:"circuit_breaker,omitempty" caddy:"namespace=http.reverse_proxy.circuit_breakers inline_key=type"`
-	LoadBalancing  *LoadBalancing   `json:"load_balancing,omitempty"`
-	HealthChecks   *HealthChecks    `json:"health_checks,omitempty"`
-	Upstreams      UpstreamPool     `json:"upstreams,omitempty"`
-	FlushInterval  caddy.Duration   `json:"flush_interval,omitempty"`
-	Headers        *headers.Handler `json:"headers,omitempty"`
-	BufferRequests bool             `json:"buffer_requests,omitempty"`
+	// Configures the method of transport for the proxy. A transport
+	// is what performs the actual "round trip" to the backend.
+	// The default transport is plaintext HTTP.
+	TransportRaw json.RawMessage `json:"transport,omitempty" caddy:"namespace=http.reverse_proxy.transport inline_key=protocol"`
+
+	// A circuit breaker may be used to relieve pressure on a backend
+	// that is beginning to exhibit symptoms of stress or latency.
+	// By default, there is no circuit breaker.
+	CBRaw json.RawMessage `json:"circuit_breaker,omitempty" caddy:"namespace=http.reverse_proxy.circuit_breakers inline_key=type"`
+
+	// Load balancing distributes load/requests between backends.
+	LoadBalancing *LoadBalancing `json:"load_balancing,omitempty"`
+
+	// Health checks update the status of backends, whether they are
+	// up or down. Down backends will not be proxied to.
+	HealthChecks *HealthChecks `json:"health_checks,omitempty"`
+
+	// Upstreams is the list of backends to proxy to.
+	Upstreams UpstreamPool `json:"upstreams,omitempty"`
+
+	// TODO: figure out good defaults and write docs for this
+	// (see https://github.com/caddyserver/caddy/issues/1460)
+	FlushInterval caddy.Duration `json:"flush_interval,omitempty"`
+
+	// Headers manipulates headers between Caddy and the backend.
+	Headers *headers.Handler `json:"headers,omitempty"`
+
+	// If true, the entire request body will be read and buffered
+	// in memory before being proxied to the backend. This should
+	// be avoided if at all possible for performance reasons.
+	BufferRequests bool `json:"buffer_requests,omitempty"`
 
 	Transport http.RoundTripper `json:"-"`
 	CB        CircuitBreaker    `json:"-"`
@@ -140,7 +181,7 @@ func (h *Handler) Provision(ctx caddy.Context) error {
 
 		timeout := time.Duration(h.HealthChecks.Active.Timeout)
 		if timeout == 0 {
-			timeout = 10 * time.Second
+			timeout = 5 * time.Second
 		}
 
 		h.HealthChecks.Active.stopChan = make(chan struct{})
@@ -649,10 +690,30 @@ func removeConnectionHeaders(h http.Header) {
 
 // LoadBalancing has parameters related to load balancing.
 type LoadBalancing struct {
-	SelectionPolicyRaw json.RawMessage          `json:"selection_policy,omitempty" caddy:"namespace=http.reverse_proxy.selection_policies inline_key=policy"`
-	TryDuration        caddy.Duration           `json:"try_duration,omitempty"`
-	TryInterval        caddy.Duration           `json:"try_interval,omitempty"`
-	RetryMatchRaw      caddyhttp.RawMatcherSets `json:"retry_match,omitempty" caddy:"namespace=http.matchers"`
+	// A selection policy is how to choose an available backend.
+	// The default policy is random selection.
+	SelectionPolicyRaw json.RawMessage `json:"selection_policy,omitempty" caddy:"namespace=http.reverse_proxy.selection_policies inline_key=policy"`
+
+	// How long to try selecting available backends for each request
+	// if the next available host is down. By default, this retry is
+	// disabled. Clients will wait for up to this long while the load
+	// balancer tries to find an available upstream host.
+	TryDuration caddy.Duration `json:"try_duration,omitempty"`
+
+	// How long to wait between selecting the next host from the pool. Default
+	// is 250ms. Only relevant when a request to an upstream host fails. Be
+	// aware that setting this to 0 with a non-zero try_duration can cause the
+	// CPU to spin if all backends are down and latency is very low.
+	TryInterval caddy.Duration `json:"try_interval,omitempty"`
+
+	// A list of matcher sets that restricts with which requests retries are
+	// allowed. A request must match any of the given matcher sets in order
+	// to be retried if the connection to the upstream succeeded but the
+	// subsequent round-trip failed. If the connection to the upstream failed,
+	// a retry is always allowed. If unspecified, only GET requests will be
+	// allowed to be retried. Note that a retry is done with the next available
+	// host according to the load balancing policy.
+	RetryMatchRaw caddyhttp.RawMatcherSets `json:"retry_match,omitempty" caddy:"namespace=http.matchers"`
 
 	SelectionPolicy Selector              `json:"-"`
 	RetryMatch      caddyhttp.MatcherSets `json:"-"`
diff --git a/modules/caddyhttp/rewrite/rewrite.go b/modules/caddyhttp/rewrite/rewrite.go
index 3a644ef..03c54b1 100644
--- a/modules/caddyhttp/rewrite/rewrite.go
+++ b/modules/caddyhttp/rewrite/rewrite.go
@@ -31,16 +31,39 @@ func init() {
 }
 
 // Rewrite is a middleware which can rewrite HTTP requests.
+//
+// The Rehandle and HTTPRedirect properties are mutually exclusive
+// (you cannot both rehandle and issue a redirect).
+//
+// These rewrite properties are applied to a request in this order:
+// Method, URI, StripPathPrefix, StripPathSuffix, URISubstring.
+//
+// TODO: This module is still a WIP and may experience breaking changes.
 type Rewrite struct {
+	// Changes the request's HTTP verb.
 	Method string `json:"method,omitempty"`
-	URI    string `json:"uri,omitempty"`
 
-	StripPathPrefix string     `json:"strip_path_prefix,omitempty"`
-	StripPathSuffix string     `json:"strip_path_suffix,omitempty"`
-	URISubstring    []replacer `json:"uri_substring,omitempty"`
+	// Changes the request's URI (path, query string, and fragment if present).
+	// Only components of the URI that are specified will be changed.
+	URI string `json:"uri,omitempty"`
+
+	// Strips the given prefix from the beginning of the URI path.
+	StripPathPrefix string `json:"strip_path_prefix,omitempty"`
 
+	// Strips the given suffix from the end of the URI path.
+	StripPathSuffix string `json:"strip_path_suffix,omitempty"`
+
+	// Performs substring replacements on the URI.
+	URISubstring []replacer `json:"uri_substring,omitempty"`
+
+	// If set to a 3xx HTTP status code and if the URI was rewritten (changed),
+	// the handler will issue a simple HTTP redirect to the new URI using the
+	// given status code.
 	HTTPRedirect caddyhttp.WeakString `json:"http_redirect,omitempty"`
-	Rehandle     bool                 `json:"rehandle,omitempty"`
+
+	// If true, the request will sent for rehandling after rewriting
+	// only if anything about the request was changed.
+	Rehandle bool `json:"rehandle,omitempty"`
 
 	logger *zap.Logger
 }
diff --git a/modules/caddyhttp/server.go b/modules/caddyhttp/server.go
index 83b90e6..60ce07e 100644
--- a/modules/caddyhttp/server.go
+++ b/modules/caddyhttp/server.go
@@ -97,8 +97,12 @@ type Server struct {
 	// in which they appear in the list.
 	Routes RouteList `json:"routes,omitempty"`
 
-	// Errors is how this server will handle errors returned from
-	// any of the handlers in the primary routes.
+	// Errors is how this server will handle errors returned from any
+	// of the handlers in the primary routes. If the primary handler
+	// chain returns an error, the error along with its recommended
+	// status code are bubbled back up to the HTTP server which
+	// executes a separate error route, specified using this property.
+	// The error routes work exactly like the normal routes.
 	Errors *HTTPErrorConfig `json:"errors,omitempty"`
 
 	// How to handle TLS connections.
@@ -418,6 +422,20 @@ func (ahc AutoHTTPSConfig) Skipped(name string, skipSlice []string) bool {
 // HTTPErrorConfig determines how to handle errors
 // from the HTTP handlers.
 type HTTPErrorConfig struct {
+	// The routes to evaluate after the primary handler
+	// chain returns an error. In an error route, extra
+	// placeholders are available:
+	//
+	// {http.error.status_code}
+	//     The recommended HTTP status code
+	// {http.error.status_text}
+	//     The status text associated with the recommended status code
+	// {http.error.message}
+	//     The error message
+	// {http.error.trace}
+	//     The origin of the error
+	// {http.error.id}
+	//     A short, human-conveyable ID for the error
 	Routes RouteList `json:"routes,omitempty"`
 }
 
diff --git a/modules/caddyhttp/starlarkmw/example/caddy.json b/modules/caddyhttp/starlarkmw/example/caddy.json
index 66f9f2c..9479d17 100644
--- a/modules/caddyhttp/starlarkmw/example/caddy.json
+++ b/modules/caddyhttp/starlarkmw/example/caddy.json
@@ -8,7 +8,7 @@
 						{
 							"handle": {
 								"handler": "starlark",
-								"script": "def setup(r):\n\t# create some middlewares specific to this request\n\ttemplates = loadModule('http.handlers.templates', {'include_root': './includes'})\n\tmidChain = execute([templates])\n\ndef serveHTTP (rw, r):\n\trw.Write('Hello world, from Starlark!')\n"
+								"script": "def setup(r):\n\t# create some middlewares specific to this request\n\ttemplates = loadModule('http.handlers.templates', {'file_root': './includes'})\n\tmidChain = execute([templates])\n\ndef serveHTTP (rw, r):\n\trw.Write('Hello world, from Starlark!')\n"
 							}
 						}
 					]
diff --git a/modules/caddyhttp/staticerror.go b/modules/caddyhttp/staticerror.go
index fd1490d..0ddebfe 100644
--- a/modules/caddyhttp/staticerror.go
+++ b/modules/caddyhttp/staticerror.go
@@ -27,8 +27,18 @@ func init() {
 }
 
 // StaticError implements a simple handler that returns an error.
+// This handler returns an error value, but does not write a response.
+// This is useful when you want the server to act as if an error
+// occurred; for example, to invoke your custom error handling logic.
+//
+// Since this handler does not write a response, the error information
+// is for use by the server to know how to handle the error.
 type StaticError struct {
-	Error      string     `json:"error,omitempty"`
+	// The recommended HTTP status code. Can be either an integer or a
+	// string if placeholders are needed. Optional. Default is 500.
+	Error string `json:"error,omitempty"`
+
+	// The error message. Optional. Default is no error message.
 	StatusCode WeakString `json:"status_code,omitempty"`
 }
 
diff --git a/modules/caddyhttp/staticresp.go b/modules/caddyhttp/staticresp.go
index 44b045e..cc294d5 100644
--- a/modules/caddyhttp/staticresp.go
+++ b/modules/caddyhttp/staticresp.go
@@ -29,10 +29,19 @@ func init() {
 
 // StaticResponse implements a simple responder for static responses.
 type StaticResponse struct {
-	StatusCode WeakString  `json:"status_code,omitempty"`
-	Headers    http.Header `json:"headers,omitempty"`
-	Body       string      `json:"body,omitempty"`
-	Close      bool        `json:"close,omitempty"`
+	// The HTTP status code to respond with. Can be an integer or,
+	// if needing to use a placeholder, a string.
+	StatusCode WeakString `json:"status_code,omitempty"`
+
+	// Header fields to set on the response.
+	Headers http.Header `json:"headers,omitempty"`
+
+	// The response body.
+	Body string `json:"body,omitempty"`
+
+	// If true, the server will close the client's connection
+	// after writing the response.
+	Close bool `json:"close,omitempty"`
 }
 
 // CaddyModule returns the Caddy module information.
diff --git a/modules/caddyhttp/subroute.go b/modules/caddyhttp/subroute.go
index a60eaf7..13453a5 100644
--- a/modules/caddyhttp/subroute.go
+++ b/modules/caddyhttp/subroute.go
@@ -37,7 +37,11 @@ func init() {
 // is only returned to the entry point at the server if there is an
 // additional error returned from the errors routes.
 type Subroute struct {
-	Routes RouteList        `json:"routes,omitempty"`
+	// The primary list of routes to compile and execute.
+	Routes RouteList `json:"routes,omitempty"`
+
+	// If the primary routes return an error, error handling
+	// can be promoted to this configuration instead.
 	Errors *HTTPErrorConfig `json:"errors,omitempty"`
 }
 
diff --git a/modules/caddyhttp/templates/caddyfile.go b/modules/caddyhttp/templates/caddyfile.go
index 5dc124f..ea6aa9f 100644
--- a/modules/caddyhttp/templates/caddyfile.go
+++ b/modules/caddyhttp/templates/caddyfile.go
@@ -47,7 +47,7 @@ func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error)
 					return nil, h.ArgErr()
 				}
 			case "root":
-				if !h.Args(&t.IncludeRoot) {
+				if !h.Args(&t.FileRoot) {
 					return nil, h.ArgErr()
 				}
 			}
diff --git a/modules/caddyhttp/vars.go b/modules/caddyhttp/vars.go
index 791203b..6299dcf 100644
--- a/modules/caddyhttp/vars.go
+++ b/modules/caddyhttp/vars.go
@@ -26,7 +26,8 @@ func init() {
 }
 
 // VarsMiddleware is an HTTP middleware which sets variables
-// in the context, mainly for use by placeholders.
+// in the context, mainly for use by placeholders. The
+// placeholders have the form: `{http.vars.variable_name}`
 type VarsMiddleware map[string]string
 
 // CaddyModule returns the Caddy module information.
-- 
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