Source file core_configuration.ml

let log_src = Logs.Src.create "sihl.core.configuration"

module Logs = (val Logs.src_log log_src : Logs.LOG)

exception Exception of string

type ('ctor, 'ty) schema = (string, 'ctor, 'ty) Conformist.t
type data = (string * string) list

type config =
  { name : string
  ; description : string
  ; type_ : string
  ; default : string option
  }

type t = config list

let make ?schema () =
  match schema with
  | Some schema ->
    Conformist.fold_left
      ~f:(fun res field ->
        let name = Conformist.Field.name field in
        let description =
          Option.value ~default:"-" (Conformist.Field.meta field)
        in
        let type_ = Conformist.Field.type_ field in
        let default = Conformist.Field.encode_default field in
        List.cons
          { name; description; type_; default = CCList.head_opt default }
          res)
      ~init:[]
      schema
  | None -> []
;;

let empty = []

(* We assume a total number of initial configurations of 100 *)
let cache = Hashtbl.create 100

let memoize f arg =
  try Hashtbl.find cache arg with
  | Not_found ->
    let result = f arg in
    (* We don't want to fill up the cache with None *)
    if Option.is_some result then Hashtbl.add cache arg result;
    result
;;

let store data =
  List.iter
    (fun (key, value) ->
      if String.equal "" value
      then ()
      else (
        Hashtbl.replace cache key (Some value);
        Unix.putenv key value))
    data
;;

let envs_to_kv envs =
  envs
  |> List.map (String.split_on_char '=')
  |> List.map (function
         | [] -> "", ""
         | [ key ] -> key, ""
         | [ key; value ] -> key, value
         | key :: values -> key, String.concat "" values)
;;

(* .env file handling *)
let root_path () =
  match Sys.getenv_opt "ROOT_PATH" with
  | None | Some "" ->
    let markers = [ ".git"; ".hg"; ".svn"; ".bzr"; "_darcs" ] in
    let rec find_markers path_els =
      let path = String.concat "/" path_els in
      if List.exists
           (fun marker -> Sys.file_exists (path ^ "/" ^ marker))
           markers
      then (
        (* Path found => Write it into the env var to "memoize" it *)
        Unix.putenv "ROOT_PATH" path;
        Some path)
      else (
        match path_els with
        | [] -> None
        | _ -> find_markers @@ CCList.take (List.length path_els - 1) path_els)
    in
    find_markers @@ String.split_on_char '/' (Unix.getcwd ())
  | Some path -> Some path
;;

let env_files_path () =
  match Sys.getenv_opt "ENV_FILES_PATH" with
  | None | Some "" -> root_path ()
  | Some path -> Some path
;;

let read_env_file () =
  match env_files_path () with
  | Some path ->
    let is_test =
      match Sys.getenv_opt "SIHL_ENV" with
      | Some "test" -> true
      | _ -> false
    in
    let filename = path ^ "/" ^ if is_test then ".env.test" else ".env" in
    let exists = CCIO.File.exists filename in
    if exists
    then (
      Logs.info (fun m -> m "Env file found: %s" filename);
      let envs = CCIO.read_lines_l (open_in filename) in
      Some (envs_to_kv envs))
    else (
      Logs.info (fun m ->
          m "Env file not found: %s. Continuing without it." filename);
      None)
  | None ->
    Logs.debug (fun m ->
        m
          "No env files directory found, please provide your own directory \
           path with environment variable ENV_FILES_PATH if you would like to \
           use env files");
    None
;;

let file_was_read = ref false

let load_env_file () =
  if !file_was_read
  then (* Nothing to do, the file was read already *) ()
  else (
    let file_configuration = read_env_file () in
    file_was_read := true;
    store (Option.value file_configuration ~default:[]))
;;

let environment_variables () =
  load_env_file ();
  Unix.environment () |> Array.to_list |> envs_to_kv
;;

let read schema =
  let data = environment_variables () in
  let data = List.map (fun (k, v) -> k, [ v ]) data in
  match Conformist.decode_and_validate schema data with
  | Ok value -> value
  | Error errors ->
    let errors =
      List.map
        (fun (field, input, msg) ->
          match CCList.head_opt input with
          | None ->
            Format.sprintf "Failed to read configuration '%s': %s" field msg
          | Some input ->
            Format.sprintf
              "Failed to read configuration '%s' for '%s': %s"
              input
              field
              msg)
        errors
    in
    List.iter (fun error -> Logs.err (fun m -> m "%s" error)) errors;
    raise (Exception "Invalid configuration provided")
;;

let read_string' key =
  load_env_file ();
  Sys.getenv_opt key
;;

let read_string = memoize read_string'

let load () =
  load_env_file ();
  match read_string "SIHL_ENV" with
  | None ->
    Logs.info (fun m ->
        m
          "SIHL_ENV not found. Set it to one of the following values: \
           development, production, test");
    failwith "SIHL_ENV not found"
  | Some env -> Logs.info (fun m -> m "SIHL_ENV: %s" env)
;;

let is_test () =
  match read_string "SIHL_ENV" with
  | Some "test" -> true
  | _ -> false
;;

let is_development () =
  match read_string "SIHL_ENV" with
  | Some "development" -> true
  | _ -> false
;;

let is_production () =
  match read_string "SIHL_ENV" with
  | Some "production" -> true
  | _ -> false
;;

let read_secret () =
  match is_production (), read_string "SIHL_SECRET" with
  | true, Some secret ->
    (* TODO [jerben] provide proper security policy (entropy or smth) *)
    if String.length secret > 10
    then secret
    else (
      Logs.err (fun m -> m "SIHL_SECRET has to be longer than 10");
      failwith "Insecure secret provided")
  | false, Some secret -> secret
  | true, None ->
    Logs.err (fun m -> m "Set SIHL_SECRET before deploying Sihl to production");
    failwith "No secret provided"
  (* In testing and local dev we don't have to use real security *)
  | false, None -> "secret"
;;

let read_int key =
  match read_string key with
  | Some value -> int_of_string_opt value
  | None -> None
;;

let read_bool key =
  match read_string key with
  | Some "1" | Some "true" | Some "True" -> Some true
  | Some "0" | Some "false" | Some "False" -> Some false
  | _ -> None
;;

let require schema = read schema |> ignore

(* Displaying configurations *)

let configuration_to_string (configurations : t) : string =
  configurations
  |> List.map (fun { name; description; type_; default } ->
         match default with
         | Some default ->
           Format.sprintf
             {|
%s
%s
Type: %s
Default: %s
|}
             name
             description
             type_
             default
         | None ->
           Format.sprintf {|
%s
%s
Type: %s
Required
|} name description type_)
  |> String.concat ""
;;

let print_cmd (configurations : t list) : Core_command.t =
  Core_command.make
    ~name:"config"
    ~description:"Prints a list of configurations that are known to Sihl."
    (fun _ ->
      configurations
      |> List.filter (fun configuration -> List.length configuration > 0)
      |> List.concat
      |> List.sort (fun c1 c2 ->
             (* We want to show required configurations first. *)
             match c1.default, c2.default with
             | Some _, Some _ -> 0
             | Some _, None -> 1
             | None, Some _ -> -1
             | None, None -> 0)
      |> configuration_to_string
      |> print_endline
      |> Option.some
      |> Lwt.return)
;;

let commands configurations = [ print_cmd configurations ]