Virtualhost config with remap rules

configs/virtualhost.yaml.default

@@ -0,0 +1,23 @@
+# virtualhost.yaml
+#
+# This configuration file defines a virtual host that provides domain-scoped configs and
+# remap rules, overriding global configs.
+#
+# Remap rule config flow:
+#   1. Resolve to a single virtualhost
+#       A. Look through exact match virtualhost domains. If found, use virtualhost config.
+#       B. Look through wildcard virtualhost doamins. If found, use virtualhost config.
+#       C. If no virtualhost config found, skip to 3.
+#   2. Within virtualhost config, use virtualhost remap rules.
+#       A. Follow existing remap.config rules. If found, use remap rule. (See remap.config for details)
+#   3. If no virtualhost or remap rule found, use global remap.config
+#
+#  Example:
+# virtualhost:
+#   - id: example
+#     domains:
+#       - example.com
+#       - "*.com"        # Only allow single left-most: "*.[domain]" format
+#
+#     remap:
+#       - map http://example.com http://origin.example.com/

doc/admin-guide/files/virtualhost.yaml.en.rst

@@ -0,0 +1,196 @@
+
+.. Licensed to the Apache Software Foundation (ASF) under one
+   or more contributor license agreements.  See the NOTICE file
+   distributed with this work for additional information
+   regarding copyright ownership.  The ASF licenses this file
+   to you under the Apache License, Version 2.0 (the
+   "License"); you may not use this file except in compliance
+   with the License.  You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing,
+   software distributed under the License is distributed on an
+   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+   KIND, either express or implied.  See the License for the
+   specific language governing permissions and limitations
+   under the License.
+
+.. include:: ../../common.defs
+
+.. configfile:: virtualhost.yaml
+
+virtualhost.yaml
+************
+
+The :file:`virtualhost.yaml` file defines configuration blocks that apply to a group of domains.
+Each virtual host entry defines a set of domains and the remap rules associated with those domains.
+Virtual host remap rules override global :file:`remap.config` rules but remain fully backward compatible
+with existing configurations. If absent, ATS behaves exactly as before.
+
+Currently, this file only supports :file:`remap.config` overrides. Future versions will expand virtual
+host support to additional configuration types (e.g. :file:`sni.yaml`, :file:`ssl_multicert.config`,
+:file:`parent.config`, etc)
+
+By default this is named :file:`virtualhost.yaml`. The filename can be changed by setting
+:ts:cv:`proxy.config.virtualhost.filename`. 
+
+
+Configuration
+=============
+
+:file:`virtualhost.yaml` is YAML format with top level namespace **virtualhost** and a list of virtual host
+entries. Each virtual host entry must provide an **id** and at least one domain defined in **domains**.
+
+An example configuration looks like:
+
+.. code-block:: yaml
+
+   virtualhost:
+     - id: example
+       domains:
+         - example.com
+
+       remap:
+         - map http://example.com http://origin.example.com/
+
+
+===================== ==========================================================
+Field Name            Description
+===================== ==========================================================
+``id``                 Virtual host identifier to perform specific operations on
+``domains``            List of domains to resolve a request to
+``remap``              List of remap rules as defined in remap.config
+===================== ==========================================================
+
+``domains``
+   Domains can be defined as request domain name or subdomains using wildcard feature.
+   Wildcard support only allows single left most ``*``. This does not support regex.
+   When matching to a virtual host entry, domains with exact match have precedence
+   over wildcard. If a domain matches to multiple wildcard domains, the virtual host
+   config defined first has precedence.
+
+   For example:
+      Supported:
+      - ``foo.example.com``
+      - ``*.example.com``
+      - ``*.com``
+
+      NOT Supported:
+      - ``foo[0-9]+.example.com`` (regex)
+      - ``bar.*.example.net`` (``*`` in the middle)
+      - ``*.bar.*.com`` (multiple ``*``)
+      - ``*.*.baz.com`` (multiple ``*``)
+      - ``baz*.example.net`` (partial wildcard)
+      - ``*baz.example.net`` (partial wildcard)
+      - ``b*z.example.net`` (partial wildcard)
+      - ``*`` (global)
+
+Evaluation Order
+----------------
+
+|TS| evaluates a request using deterministic precedence in the following order:
+
+1. Resolve to a single virtualhost
+   a. Check for an exact domain match. If any virtual host lists the request hostname explicitly,
+      that virtual host is selected. 
+   b. Check for a wildcard domain match. If any virtual host wildcard domains define a subdomain 
+      of the request hostname in the form ``*.[domain]``, that virtual host is selected.
+   c. If no matching virtual host exists, the request proceeds using global configuration
+      (i.e :file:`remap.config`). Skip to step 3.
+2. Within selected virtual host config, use virtual host remap rules.
+   a. Follow existing :file:`remap.config` rules and matching orders. If a matching remap rule
+      is found, that remap rule is selected.
+3. If neither virtual host nor remap rules match, ATS falls back to global :file:`remap.config` resolution.
+
+Only one virtual host entry may match a given request. If multiple entries could match, ATS uses the first matching
+entry defined in :file:`virtualhost.yaml`.
+
+
+Granular Reload
+===============
+
+|TS| now supports granular configuration reloads for individual virtual hosts defined in :file:`virtualhost.yaml`.
+In addition to reloading the entire |TS| configuration with :option:`traffic_ctl config reload`, users can
+selectively reload a single virtual host entry without affecting other virtual host entries.
+
+By only updating the necessary changes, this reduces configuration deployment time and improves visibility on the changes made.
+
+To reload for a specific virtual host, use:
+
+::
+
+   $ traffic_ctl config reload --virtualhost <id>
+
+Where **<id>** is the virtual host ID defined in :file:`virtualhost.yaml`. Only the **<id>** virtual host
+configuration will be reloaded. This does not affect other virtual hosts or global configuration files.
+
+Example:
+
+::
+
+   $ traffic_ctl config reload --virtualhost foo
+   ┌ Virtualhost: foo
+   └┬ Reload status: ok
+    ├ Message: Virtualhost successfully reloaded
+
+
+Examples
+========
+
+.. code-block:: yaml
+
+   # virtualhost.yaml
+   virtualhost:
+     - id: example
+       domains:
+         - example.com
+
+       remap:
+         - map http://example.com/ http://origin.example.com/
+
+   # remap.config
+   map / http://other.example.com/
+
+This rules translates in the following translation.
+
+================================================ ========================================================
+Client Request                                   Translated Request
+================================================ ========================================================
+``http://example.com/index.html``                ``http://origin.example.com/index.html``
+``http://www.x.com/index.html``                  ``http://other.example.com/index.html``
+================================================ ========================================================
+
+.. code-block:: yaml
+
+   # virtualhost.yaml
+   virtualhost:
+     - id: example
+       domains:
+         - "*.example.com"
+
+       remap:
+         - regex_map http://sub[0-9]+.example.com/ http://origin$1.example.com/
+
+      - id: foo
+       domains:
+         - foo.example.com
+
+       remap:
+         - map http:/foo.example.com/ http://foo.origin.com/
+
+This rules translates in the following translation.
+
+================================================ ========================================================
+Client Request                                   Translated Request
+================================================ ========================================================
+``http://sub0.example.com/index.html``           ``http://origin0.example.com/index.html``
+``http://foo.example.com/index.html``            ``http://foo.origin.com/index.html``
+``http://bar.example.com/index.html``             No remap rule found in virtual host entry `example`
+================================================ ========================================================
+
+
+See Also
+========
+
+:ref:`remap.config`

include/mgmt/rpc/handlers/config/Configuration.h

@@ -26,5 +26,6 @@ namespace rpc::handlers::config
 {
 swoc::Rv<YAML::Node> set_config_records(std::string_view const &id, YAML::Node const &params);
 swoc::Rv<YAML::Node> reload_config(std::string_view const &id, YAML::Node const &params);
+swoc::Rv<YAML::Node> reload_virtualhost_config(std::string_view const &id, YAML::Node const &params);
 
 } // namespace rpc::handlers::config

include/proxy/VirtualHost.h

@@ -0,0 +1,107 @@
+/** @file
+
+  Virtual Host configuration
+
+  @section license License
+
+  Licensed to the Apache Software Foundation (ASF) under one
+  or more contributor license agreements.  See the NOTICE file
+  distributed with this work for additional information
+  regarding copyright ownership.  The ASF licenses this file
+  to you under the Apache License, Version 2.0 (the
+  "License"); you may not use this file except in compliance
+  with the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+ */
+
+#pragma once
+
+#include <string>
+#include <string_view>
+
+#include "iocore/eventsystem/ConfigProcessor.h"
+#include "proxy/http/remap/UrlRewrite.h"
+#include "tscore/Ptr.h"
+
+class VirtualHostConfig : public ConfigInfo
+{
+public:
+  VirtualHostConfig() = default;
+  VirtualHostConfig(const VirtualHostConfig &other)
+    : _entries(other._entries),
+      _exact_domains_to_id(other._exact_domains_to_id),
+      _wildcard_domains_to_id(other._wildcard_domains_to_id)
+  {
+  }
+  VirtualHostConfig &
+  operator=(const VirtualHostConfig &other)
+  {
+    if (this != &other) {
+      _entries                = other._entries;
+      _exact_domains_to_id    = other._exact_domains_to_id;
+      _wildcard_domains_to_id = other._wildcard_domains_to_id;
+    }
+    return *this;
+  }
+  ~VirtualHostConfig() = default;
+
+  struct Entry : public RefCountObjInHeap {
+    std::string              id;
+    std::vector<std::string> exact_domains;
+    std::vector<std::string> wildcard_domains;
+    Ptr<UrlRewrite>          remap_table;
+
+    Entry      *acquire() const;
+    void        release() const;
+    std::string get_id() const;
+  };
+
+  bool        load();
+  bool        set_entry(std::string_view id, Ptr<Entry> &entry);
+  static bool load_entry(std::string_view id, Ptr<Entry> &entry);
+  Ptr<Entry>  find_by_id(std::string_view id) const;
+  Ptr<Entry>  find_by_domain(std::string_view domain) const;
+
+private:
+  using entry_map = std::unordered_map<std::string, Ptr<Entry>>;
+  using name_map  = std::unordered_map<std::string, std::string>;
+
+  entry_map _entries;
+  name_map  _exact_domains_to_id;
+  name_map  _wildcard_domains_to_id;
+};
+
+class VirtualHost
+{
+public:
+  using scoped_config = ConfigProcessor::scoped_config<VirtualHost, VirtualHostConfig>;
+
+  static void               startup();
+  static int                reconfigure();
+  static int                reconfigure(std::string_view id);
+  static VirtualHostConfig *acquire();
+  static void               release(VirtualHostConfig *config);
+
+private:
+  static int config_callback(const char *, RecDataT, RecData, void *);
+  static int _configid;
+};
+
+struct VirtualHostConfigContinuation : public Continuation {
+  VirtualHostConfigContinuation() : Continuation(nullptr) { SET_HANDLER(&VirtualHostConfigContinuation::reconfigure); }
+
+  int
+  reconfigure(int /* event ATS_UNUSED */, Event * /* e ATS_UNUSED */)
+  {
+    VirtualHost::reconfigure();
+    delete this;
+    return EVENT_DONE;
+  }
+};

include/proxy/http/HttpSM.h

@@ -45,6 +45,7 @@
 #include "api/InkAPIInternal.h"
 #include "proxy/ProxyTransaction.h"
 #include "proxy/hdrs/HdrUtils.h"
+#include "proxy/VirtualHost.h"
 
 // inknet
 #include "proxy/http/PreWarmManager.h"
@@ -306,7 +307,8 @@ class HttpSM : public Continuation, public PluginUserArgs<TS_USER_ARGS_TXN>
 
   // This unfortunately can't go into the t_state, because of circular dependencies. We could perhaps refactor
   // this, with a lot of work, but this is easier for now.
-  UrlRewrite *m_remap = nullptr;
+  UrlRewrite               *m_remap             = nullptr;
+  VirtualHostConfig::Entry *m_virtualhost_entry = nullptr;
 
   History<HISTORY_DEFAULT_SIZE> history;
   NetVConnection *
@@ -364,6 +366,7 @@ class HttpSM : public Continuation, public PluginUserArgs<TS_USER_ARGS_TXN>
 
   // Y! ebalsa: remap handlers
   int  state_remap_request(int event, void *data);
+  void set_virtualhost_entry(std::string_view domain);
   void do_remap_request(bool);
 
   // Cache Handlers

include/proxy/http/remap/RemapConfig.h

@@ -25,6 +25,11 @@
 
 #include "proxy/http/remap/AclFiltering.h"
 
+namespace YAML
+{
+class Node;
+}
+
 class UrlRewrite;
 
 #define BUILD_TABLE_MAX_ARGS 2048
@@ -79,15 +84,15 @@ struct BUILD_TABLE_INFO {
 };
 
 const char *remap_parse_directive(BUILD_TABLE_INFO *bti, char *errbuf, size_t errbufsize);
-bool        remap_parse_config_bti(const char *path, BUILD_TABLE_INFO *bti);
+bool        remap_parse_config_bti(const char *path, BUILD_TABLE_INFO *bti, YAML::Node const *remap_node = nullptr);
 
 const char *remap_validate_filter_args(acl_filter_rule **rule_pp, const char *const *argv, int argc, char *errStrBuf,
                                        size_t errStrBufSize, ACLBehaviorPolicy behavior_policy);
 
 unsigned long remap_check_option(const char *const *argv, int argc, unsigned long findmode = 0, int *_ret_idx = nullptr,
                                  const char **argptr = nullptr);
 
-bool remap_parse_config(const char *path, UrlRewrite *rewrite);
+bool remap_parse_config(const char *path, UrlRewrite *rewrite, YAML::Node const *remap_node);
 
 using load_remap_file_func = void (*)(const char *, const char *);