build: generate document to dashboard priv dir

apps/emqx_conf/etc/emqx_conf.md

@@ -0,0 +1,192 @@
+EMQ X configuration file is in [HOCON](https://github.com/emqx/hocon) format.
+HOCON, or Human-Optimized Config Object Notation is a format for human-readable data,
+and a superset of JSON.
+
+## Syntax
+
+In config file the values can be notated as JSON like ojbects, such as
+```
+node {
+    name = "emqx@127.0.0.1"
+    cookie = "mysecret"
+}
+```
+
+Another equivalent representation is flat, suh as
+
+```
+node.name="127.0.0.1"
+node.cookie="mysecret"
+```
+
+This flat format is almost backward compatible with EMQ X's config file format
+in 4.x series (the so called 'cuttlefish' format).
+
+It is 'almost' compabile because the often HOCON requires strings to be quoted,
+while cuttlefish treats all characters to the right of the `=` mark as the value.
+
+e.g. cuttlefish: `node.name = emqx@127.0.0.1`, HOCON: `node.name = "emqx@127.0.0.1"`
+
+Strings without special characters in them can be unquoted in HOCON too,
+e.g. `foo`, `foo_bar`, `foo_bar_1`:
+
+For more HOCON syntax, pelase refer to the [specification](https://github.com/lightbend/config/blob/main/HOCON.md)
+
+## Schema
+
+To make the HOCON objects type-safe, EMQ X introduded a schema for it.
+The schema defines data types, and data fields' names and metadata for config value validation
+and more. In fact, this config document itself is generated from schema metadata.
+
+### Complex Data Types
+
+There are 4 complex data types in EMQ X's HOCON config:
+
+1. Struct: Named using an unquoted string, followed by a pre-defined list of fields,
+   fields can not start with a number, and are only allowed to use
+   lowercase letters and underscores as word separater.
+1. Map: Map is like Struct, however the fields are not pre-defined.
+   1-based index number can also be used as map keys for an alternative
+   representation of an Array.
+1. Union: `MemberType1 | MemberType2 | ...`
+1. Array: `[ElementType]`
+
+### Primitive Data Types
+
+Complex types define data 'boxes' wich may contain other complex data
+or primitive values.
+There are quite some different primitive types, to name a fiew:
+
+* `atom()`
+* `boolean()`
+* `string()`
+* `integer()`
+* `float()`
+* `number()`
+* `binary()` # another format of string()
+* `emqx_schema:duration()` # time duration, another format of integer()
+* ...
+
+The primitive types are mostly self-describing, some are built-in, such
+as `atom()`, some are defiend in EMQ X modules, such as `emqx_schema:duration()`.
+
+### Config Paths
+
+If we consider the whole EMQ X config as a tree,
+to reference a primitive value, we can use a dot-separated names form string for
+the path from the tree-root (always a Struct) down to the primitive values at tree-leaves.
+
+Each segment of the dotted string is a Struct filed name or Map key.
+For Array elements, 1-based index is used.
+
+below are some examples
+
+```
+node.name="emqx.127.0.0.1"
+zone.zone1.max_packet_size="10M"
+authentication.1.enable=true
+```
+
+### Environment varialbes
+
+Environment variables can be used to define or override config values.
+
+Due to the fact that dots (`.`) are not allowed in environment variables, dots are
+replaced with double-underscores (`__`).
+
+And a the `EMQX_` prefix is used as the namespace.
+
+For example `node.name` can be represented as `EMQX_NODE__NAME`
+
+Environment varialbe values are parsed as hocon values, this allows users
+to even set complex values from environment variables.
+
+For example, this environment variable sets an array value.
+
+```
+export EMQX_LISTENERS__SSL__L1__AUTHENTICATION__SSL__CIPHERS="[\"TLS_AES_256_GCM_SHA384\"]"
+```
+
+Unknown environment variables are logged as a `warning` level log, for example:
+
+```
+[warning] unknown_env_vars: ["EMQX_AUTHENTICATION__ENABLED"]
+```
+
+because the field name is `enable`, not `enabled`.
+
+<strong>NOTE:</strong> Unknown root keys are however silently discarded.
+
+### Config overlay
+
+HOCON values are overlayed, earlier defined values are at layers closer to the bottom.
+The overall order of the overlay rules from bottom up are:
+
+1. `emqx.conf` the base config file
+1. `EMQX_` prfixed environment variables
+1. Cluster override file, the path of which is configured as `cluster_override_conf_file` in the lower layers
+1. Local override file, the path of which is configured as `local_override_conf_file` in the lower layers
+
+Below are the rules of config value overlay.
+
+#### Struct Fileds
+
+Later config values overwrites earlier values.
+For example, in below config, the last line `debug` overwrites `errro` for
+console log handler's `level` config, but leaving `enable` unchanged.
+```
+log {
+    console_handler{
+        enable=true,
+        level=error
+    }
+}
+
+## ... more configs ...
+
+log.console_handler.level=debug
+```
+
+#### Map Values
+
+Maps are like structs, only the files are user-defined rather than
+the config schema. For instance, `zone1` in the exampele below.
+
+```
+zone {
+    zone1 {
+        mqtt.max_packet_size = 1M
+    }
+}
+
+## The maximum packet size can be defined as above,
+## then overriden as below
+
+zone.zone1.mqtt.max_packet_size = 10M
+```
+
+#### Array Elements
+
+Arrays in EMQ X config have two different representations
+
+* list, such as: `[1, 2, 3]`
+* indexed-map, such as: `{"1"=1, "2"=2, "3"=3}`
+
+Dot-separated paths with number in it are parsed to indexed-maps
+e.g. `authentication.1={...}` is parsed as `authentication={"1": {...}}`
+
+Indexed-map arrays can be used to override list arrays:
+
+```
+authentication=[{enable=true, backend="built-in-database", mechanism="password-based"}]
+# we can disable this authentication provider with:
+authentication.1.enable=false
+```
+However, list arrays do not get recursively merged into indexed-map arrays.
+e.g.
+
+```
+authentication=[{enable=true, backend="built-in-database", mechanism="password-based"}]
+## below value will replace the whole array, but not to override just one field.
+authentication=[{enable=true}]
+```

apps/emqx_conf/src/emqx_conf.erl

@@ -24,6 +24,7 @@
 -export([update/3, update/4]).
 -export([remove/2, remove/3]).
 -export([reset/2, reset/3]).
+-export([gen_doc/1]).
 
 %% for rpc
 -export([get_node_and_config/1]).
@@ -123,6 +124,16 @@ reset(Node, KeyPath, Opts) when Node =:= node() ->
 reset(Node, KeyPath, Opts) ->
     rpc:call(Node, ?MODULE, reset, [KeyPath, Opts]).
 
+-spec gen_doc(file:name_all()) -> ok.
+gen_doc(File) ->
+    Version = emqx_release:version(),
+    Title = "# EMQ X " ++ Version ++ " Configuration",
+    BodyFile = filename:join([code:lib_dir(emqx_conf), "etc", "emqx_conf.md"]),
+    {ok, Body} = file:read_file(BodyFile),
+    Doc = hocon_schema_doc:gen(emqx_conf_schema, #{title => Title,
+                                                   body => Body}),
+    file:write_file(File, Doc).
+
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------

build

@@ -51,16 +51,17 @@ log() {
     echo "===< $msg"
 }
 
-docgen() {
+make_doc() {
     local libs_dir1 libs_dir2
     libs_dir1="$(find "_build/default/lib/" -maxdepth 2 -name ebin -type d)"
     libs_dir2="$(find "_build/$PROFILE/lib/" -maxdepth 2 -name ebin -type d)"
 
-    local conf_doc_markdown
-    conf_doc_markdown="$(pwd)/_build/${PROFILE}/rel/emqx/etc/emqx-config-doc.md"
-    echo "===< Generating config document $conf_doc_markdown"
+    local conf_doc_md
+    # TODO render md as html
+    conf_doc_md="$(pwd)/_build/${PROFILE}/lib/emqx_dashboard/priv/config.md"
+    echo "===< Generating config document $conf_doc_md"
     # shellcheck disable=SC2086
-    erl -noshell -pa $libs_dir1 $libs_dir2 -eval "file:write_file('$conf_doc_markdown', hocon_schema_doc:gen(emqx_conf_schema, \"EMQ X ${PKG_VSN} Configuration\")), halt(0)."
+    erl -noshell -pa $libs_dir1 $libs_dir2 -eval "ok = emqx_conf:gen_doc(\"${conf_doc_md}\"), halt(0)."
 }
 
 make_rel() {
@@ -70,7 +71,6 @@ make_rel() {
         echo "gpb should not be included in the release"
         exit 1
     fi
-    docgen
 }
 
 ## unzip previous version .zip files to _build/$PROFILE/rel/emqx/releases before making relup
@@ -205,6 +205,9 @@ make_docker_testing() {
 log "building artifact=$ARTIFACT for profile=$PROFILE"
 
 case "$ARTIFACT" in
+    doc)
+        make_doc
+        ;;
     rel)
         make_rel
         ;;

rebar.config.erl

@@ -153,36 +153,42 @@ profiles() ->
        , {relx, relx(Vsn, cloud, bin, ce)}
        , {overrides, prod_overrides()}
        , {project_app_dirs, project_app_dirs(ce)}
+       , {post_hooks, [{compile, "./build emqx doc"}]}
        ]}
     , {'emqx-pkg',
        [ {erl_opts, prod_compile_opts()}
        , {relx, relx(Vsn, cloud, pkg, ce)}
        , {overrides, prod_overrides()}
        , {project_app_dirs, project_app_dirs(ce)}
+       , {post_hooks, [{compile, "./build emqx-pkg doc"}]}
        ]}
     , {'emqx-enterprise',
        [ {erl_opts, prod_compile_opts()}
        , {relx, relx(Vsn, cloud, bin, ee)}
        , {overrides, prod_overrides()}
        , {project_app_dirs, project_app_dirs(ee)}
+       , {post_hooks, [{compile, "./build emqx-enterprise doc"}]}
        ]}
     , {'emqx-enterprise-pkg',
        [ {erl_opts, prod_compile_opts()}
        , {relx, relx(Vsn, cloud, pkg, ee)}
        , {overrides, prod_overrides()}
        , {project_app_dirs, project_app_dirs(ee)}
+       , {post_hooks, [{compile, "./build emqx-enterprise-pkg doc"}]}
        ]}
     , {'emqx-edge',
        [ {erl_opts, prod_compile_opts()}
        , {relx, relx(Vsn, edge, bin, ce)}
        , {overrides, prod_overrides()}
        , {project_app_dirs, project_app_dirs(ce)}
+       , {post_hooks, [{compile, "./build emqx-edge doc"}]}
        ]}
     , {'emqx-edge-pkg',
        [ {erl_opts, prod_compile_opts()}
        , {relx, relx(Vsn, edge, pkg, ce)}
        , {overrides, prod_overrides()}
        , {project_app_dirs, project_app_dirs(ce)}
+       , {post_hooks, [{compile, "./build emqx-edge-pkg doc"}]}
        ]}
     , {check,
        [ {erl_opts, common_compile_opts()}