cfg: make ctx store a hash tbl mapping urls to cfgs

Author: yasunariw

lib/action.ml

@@ -93,13 +93,14 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
     if List.is_empty matched_channel_names then default else matched_channel_names
 
   let partition_status (ctx : Context.t) (n : status_notification) =
-    let cfg = Context.get_config_exn ctx in
+    let repo = n.repository in
+    let cfg = Context.find_repo_config_exn ctx repo.url in
     let pipeline = n.context in
     let current_status = n.state in
     let rules = cfg.status_rules.rules in
     let action_on_match (branches : branch list) =
       let default = Option.to_list cfg.prefix_rules.default_channel in
-      let () = Context.refresh_pipeline_status ~pipeline ~branches ~status:current_status ctx in
+      let () = Context.refresh_pipeline_status ctx repo.url ~pipeline ~branches ~status:current_status in
       match List.is_empty branches with
       | true -> Lwt.return []
       | false ->
@@ -111,13 +112,12 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
       | false -> Lwt.return default
       | true ->
         let sha = n.commit.sha in
-        let repo = n.repository in
         ( match%lwt Github_api.get_api_commit ~ctx ~repo ~sha with
         | Error e -> action_error e
         | Ok commit -> Lwt.return @@ partition_commit cfg commit.files
         )
     in
-    if Context.is_pipeline_allowed ctx ~pipeline then begin
+    if Context.is_pipeline_allowed ctx repo.url ~pipeline then begin
       match Rule.Status.match_rules ~rules n with
       | Some Ignore | None -> Lwt.return []
       | Some Allow -> action_on_match n.branches
@@ -136,7 +136,7 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
     else Lwt.return []
 
   let partition_commit_comment (ctx : Context.t) n =
-    let cfg = Context.get_config_exn ctx in
+    let cfg = Context.find_repo_config_exn ctx n.repository.url in
     match n.comment.commit_id with
     | None -> action_error "unable to find commit id for this commit comment event"
     | Some sha ->
@@ -155,7 +155,8 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
       )
 
   let generate_notifications (ctx : Context.t) req =
-    let cfg = Context.get_config_exn ctx in
+    let repo = Github.repo_of_notification req in
+    let cfg = Context.find_repo_config_exn ctx repo.url in
     match req with
     | Github.Push n ->
       partition_push cfg n |> List.map ~f:(fun (channel, n) -> generate_push_notification n channel) |> Lwt.return
@@ -184,20 +185,20 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
     in
     Lwt_list.iter_s notify notifications
 
-  (** [refresh_config_of_context ctx n] updates the current context if the configuration
-      hasn't been loaded yet, or if the incoming request [n] is a push
+  (** [refresh_repo_config ctx n] fetches the latest repo config if it's
+      uninitialized, or if the incoming request [n] is a push
       notification containing commits that touched the config file. *)
-  let refresh_config_of_context (ctx : Context.t) notification =
+  let refresh_repo_config (ctx : Context.t) notification =
+    let repo = Github.repo_of_notification notification in
     let fetch_config () =
-      let repo = Github.repo_of_notification notification in
       match%lwt Github_api.get_config ~ctx ~repo with
       | Ok config ->
-        ctx.config <- Some config;
-        Context.print_config ctx;
+        Context.set_repo_config ctx repo.url config;
+        Context.print_config ctx repo.url;
         Lwt.return @@ Ok ()
       | Error e -> action_error e
     in
-    match ctx.config with
+    match Context.find_repo_config ctx repo.url with
     | None -> fetch_config ()
     | Some _ ->
     match notification with
@@ -214,7 +215,7 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
       match Github.parse_exn ~secret:secrets.gh_hook_token headers body with
       | exception exn -> Exn_lwt.fail ~exn "failed to parse payload"
       | payload ->
-        ( match%lwt refresh_config_of_context ctx payload with
+        ( match%lwt refresh_repo_config ctx payload with
         | Error e -> action_error e
         | Ok () ->
           let%lwt notifications = generate_notifications ctx payload in

lib/context.ml

@@ -4,14 +4,14 @@ open Devkit
 
 exception Context_error of string
 
-let context_error msg = raise (Context_error msg)
+let context_error fmt = Printf.ksprintf (fun msg -> raise (Context_error msg)) fmt
 
 type t = {
   config_filename : string;
   secrets_filepath : string;
   state_filepath : string option;
   mutable secrets : Config_t.secrets option;
-  mutable config : Config_t.config option;
+  config : Config_t.config Stringtbl.t;
   state : State_t.state;
 }
 
@@ -21,7 +21,7 @@ let default : t =
     secrets_filepath = "secrets.json";
     state_filepath = None;
     secrets = None;
-    config = None;
+    config = Stringtbl.empty ();
     state = State.empty;
   }
 
@@ -35,30 +35,34 @@ let get_secrets_exn ctx =
   | None -> context_error "secrets is uninitialized"
   | Some secrets -> secrets
 
-let get_config_exn ctx =
-  match ctx.config with
-  | None -> context_error "config is uninitialized"
+let find_repo_config ctx repo_url = Stringtbl.find ctx.config repo_url
+
+let find_repo_config_exn ctx repo_url =
+  match find_repo_config ctx repo_url with
+  | None -> context_error "config uninitialized for repo %s" repo_url
   | Some config -> config
 
+let set_repo_config ctx repo_url config = Stringtbl.set ctx.config ~key:repo_url ~data:config
+
 let hook_of_channel ctx channel_name =
   let secrets = get_secrets_exn ctx in
   match List.find secrets.slack_hooks ~f:(fun webhook -> String.equal webhook.channel channel_name) with
   | Some hook -> Some hook.url
   | None -> None
 
-(** [is_pipeline_allowed ctx p] returns [true] if [ctx.config.status_rules]
-    doesn't define a whitelist of allowed pipelines, or if the list
-    contains pipeline [p]; returns [false] otherwise. *)
-let is_pipeline_allowed ctx ~pipeline =
-  match ctx.config with
+(** [is_pipeline_allowed ctx repo_url ~pipeline] returns [true] if [status_rules]
+    doesn't define a whitelist of allowed pipelines in the config of [repo_url],
+    or if the list contains [pipeline]; returns [false] otherwise. *)
+let is_pipeline_allowed ctx repo_url ~pipeline =
+  match find_repo_config ctx repo_url with
   | None -> true
   | Some config ->
   match config.status_rules.allowed_pipelines with
   | Some allowed_pipelines when not @@ List.exists allowed_pipelines ~f:(String.equal pipeline) -> false
   | _ -> true
 
-let refresh_pipeline_status ctx ~pipeline ~(branches : Github_t.branch list) ~status =
-  if is_pipeline_allowed ctx ~pipeline then State.refresh_pipeline_status ctx.state ~pipeline ~branches ~status else ()
+let refresh_pipeline_status ctx repo_url ~pipeline ~(branches : Github_t.branch list) ~status =
+  if is_pipeline_allowed ctx repo_url ~pipeline then State.refresh_pipeline_status ctx.state ~pipeline ~branches ~status
 
 let log = Log.from "context"
 
@@ -90,8 +94,8 @@ let refresh_state ctx =
     end
     else Ok ctx
 
-let print_config ctx =
-  let cfg = get_config_exn ctx in
+let print_config ctx repo_url =
+  let cfg = find_repo_config_exn ctx repo_url in
   let secrets = get_secrets_exn ctx in
   log#info "using prefix routing:";
   Rule.Prefix.print_prefix_routing cfg.prefix_rules.rules;