feat: show erlang and spidermonkey version in /_node/_local/_versions

The endpoint is admin-only.

Closes #3298

4 files changed, 17 insertions, 3 deletions

diff --git a/rebar.config.script b/rebar.config.script
index 8267fc13e..e3743ad9d 100644
--- a/rebar.config.script
+++ b/rebar.config.script
@@ -27,7 +27,6 @@ end.
 VerList = lists:map(fun(X) -> {Int, _} = string:to_integer(X), Int end,
     string:tokens(VerString, ".")).
 
-
 DisplayMsg = fun(Msg, Args) ->
     Base = iolist_to_binary(io_lib:format(Msg, Args)),
     Lines = binary:split(Base, <<"\n">>, [global]),
@@ -202,7 +201,7 @@ AddConfig = [
     {deps, lists:map(MakeDep, DepDescs ++ OptionalDeps)},
     {sub_dirs, SubDirs},
     {lib_dirs, ["src"]},
-    {erl_opts, [{i, "../"}] ++ ErlOpts},
+    {erl_opts, [{i, "../"}] ++ [{d, 'COUCHDB_ERLANG_VERSION', VerString}] ++ ErlOpts},
     {eunit_opts, [verbose, {report,{eunit_surefire,[{dir,"."}]}}]},
     {plugins, [eunit_plugin]},
     {dialyzer, [
diff --git a/src/chttpd/src/chttpd_node.erl b/src/chttpd/src/chttpd_node.erl
index d3d3ff7f8..feabcb9c2 100644
--- a/src/chttpd/src/chttpd_node.erl
+++ b/src/chttpd/src/chttpd_node.erl
@@ -31,6 +31,18 @@ handle_node_req(#httpd{path_parts=[_, <<"_local">>]}=Req) ->
     send_json(Req, 200, {[{name, node()}]});
 handle_node_req(#httpd{path_parts=[A, <<"_local">>|Rest]}=Req) ->
     handle_node_req(Req#httpd{path_parts=[A, node()] ++ Rest});
+% GET /_node/$node/_versions
+handle_node_req(#httpd{method='GET', path_parts=[_, Node, <<"_versions">>]}=Req) ->
+    send_json(Req, 200, {[
+        {erlang_version, ?l2b(?COUCHDB_ERLANG_VERSION)},
+        {javascript_engine, {[
+            {name, <<"spidermonkey">>},
+            {version, couch_server:get_spidermonkey_version()}
+        ]}}
+    ]});
+handle_node_req(#httpd{path_parts=[_, _Node, <<"_versions">>]}=Req) ->
+    send_method_not_allowed(Req, "GET");
+
 % GET /_node/$node/_config
 handle_node_req(#httpd{method='GET', path_parts=[_, Node, <<"_config">>]}=Req) ->
     Grouped = lists:foldl(fun({{Section, Key}, Value}, Acc) ->
diff --git a/src/couch/rebar.config.script b/src/couch/rebar.config.script
index a6d700518..b03d70d5c 100644
--- a/src/couch/rebar.config.script
+++ b/src/couch/rebar.config.script
@@ -228,6 +228,7 @@ AddConfig = [
     {erl_opts, PlatformDefines ++ [
         {d, 'COUCHDB_VERSION', Version},
         {d, 'COUCHDB_GIT_SHA', GitSha},
+        {d, 'COUCHDB_SPIDERMONKEY_VERSION', SMVsn},
         {i, "../"}
     ] ++ MD5Config ++ ProperConfig},
     {port_env, PortEnvOverrides},
diff --git a/src/couch/src/couch_server.erl b/src/couch/src/couch_server.erl
index 04e8c6cf9..5dc0a05f0 100644
--- a/src/couch/src/couch_server.erl
+++ b/src/couch/src/couch_server.erl
@@ -28,7 +28,7 @@
 -export([lock/2, unlock/1]).
 -export([db_updated/1]).
 -export([num_servers/0, couch_server/1, couch_dbs_pid_to_name/1, couch_dbs/1]).
--export([aggregate_queue_len/0]).
+-export([aggregate_queue_len/0,get_spidermonkey_version/0]).
 
 % config_listener api
 -export([handle_config_change/5, handle_config_terminate/3]).
@@ -85,6 +85,8 @@ get_stats() ->
     lists:foldl(Fun, {0, 0}, lists:seq(1, num_servers())),
     [{start_time, ?l2b(Time)}, {dbs_open, Open}].
 
+get_spidermonkey_version() -> list_to_binary(?COUCHDB_SPIDERMONKEY_VERSION).
+
 sup_start_link(N) ->
     gen_server:start_link({local, couch_server(N)}, couch_server, [N], []).