feat: implement bouncer

This service authorizes calls and converts extensions to users. This
information can be used in Asterisk to take action.

Makefile

@@ -4,4 +4,4 @@ docs:
 	swag init --generalInfo cmd/main.go --outputTypes=yaml
 
 swagger:
-	docker run --detach -p 4000:8080 -e API_URL=/doc/swagger.yaml --mount 'type=bind,src=$(shell pwd)/docs,dst=/usr/share/nginx/html/doc' swaggerapi/swagger-ui
+	docker run --detach --name eryth-swagger -p 4000:8080 -e API_URL=/doc/swagger.yaml --mount 'type=bind,src=$(shell pwd)/docs,dst=/usr/share/nginx/html/doc' swaggerapi/swagger-ui

cmd/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"context"
 	"fmt"
+	"github.com/crazybolillo/eryth/internal/bouncer"
 	"github.com/crazybolillo/eryth/internal/handler"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
@@ -75,6 +76,10 @@ func serve(ctx context.Context) error {
 	endpoint := handler.Endpoint{Conn: conn}
 	r.Mount("/endpoint", endpoint.Router())
 
+	checker := &bouncer.Bouncer{Conn: conn}
+	authorization := handler.Authorization{Bouncer: checker}
+	r.Mount("/bouncer", authorization.Router())
+
 	slog.Info("Listening on :8080")
 	return http.ListenAndServe(":8080", r)
 }

docs/swagger.yaml

@@ -1,4 +1,18 @@
 definitions:
+  bouncer.Response:
+    properties:
+      allow:
+        type: boolean
+      destination:
+        type: string
+    type: object
+  handler.AuthorizationRequest:
+    properties:
+      endpoint:
+        type: string
+      extension:
+        type: string
+    type: object
   handler.createEndpointRequest:
     properties:
       codecs:
@@ -43,6 +57,31 @@ info:
   title: Asterisk Administration API
   version: "1.0"
 paths:
+  /bouncer:
+    post:
+      consumes:
+      - application/json
+      parameters:
+      - description: Action to be reviewed
+        in: body
+        name: payload
+        required: true
+        schema:
+          $ref: '#/definitions/handler.AuthorizationRequest'
+      produces:
+      - application/json
+      responses:
+        "200":
+          description: OK
+          schema:
+            $ref: '#/definitions/bouncer.Response'
+        "400":
+          description: Bad Request
+        "500":
+          description: Internal Server Error
+      summary: Determine whether the specified action (call) is allowed or not.
+      tags:
+      - bouncer
   /endpoint:
     post:
       consumes:

internal/bouncer/bouncer.go

@@ -0,0 +1,43 @@
+package bouncer
+
+import (
+	"context"
+	"github.com/crazybolillo/eryth/internal/db"
+	"github.com/crazybolillo/eryth/internal/sqlc"
+	"github.com/jackc/pgx/v5"
+	"log/slog"
+)
+
+type Response struct {
+	Allow       bool   `json:"allow"`
+	Destination string `json:"destination"`
+}
+
+type Bouncer struct {
+	*pgx.Conn
+}
+
+func (b *Bouncer) Check(ctx context.Context, endpoint, dialed string) Response {
+	result := Response{
+		Allow:       false,
+		Destination: "",
+	}
+
+	tx, err := b.Begin(ctx)
+	if err != nil {
+		slog.Error("Unable to start transaction", slog.String("reason", err.Error()))
+		return result
+	}
+
+	queries := sqlc.New(tx)
+	destination, err := queries.GetEndpointByExtension(ctx, db.Text(dialed))
+	if err != nil {
+		slog.Error("Failed to retrieve endpoint", slog.String("dialed", dialed), slog.String("reason", err.Error()))
+		return result
+	}
+
+	return Response{
+		Allow:       true,
+		Destination: destination,
+	}
+}

internal/handler/authorization.go

@@ -0,0 +1,63 @@
+package handler
+
+import (
+	"context"
+	"encoding/json"
+	"github.com/crazybolillo/eryth/internal/bouncer"
+	"github.com/go-chi/chi/v5"
+	"log/slog"
+	"net/http"
+)
+
+type CallBouncer interface {
+	Check(ctx context.Context, endpoint, dialed string) bouncer.Response
+}
+
+type Authorization struct {
+	Bouncer CallBouncer
+}
+
+type AuthorizationRequest struct {
+	From      string `json:"endpoint"`
+	Extension string `json:"extension"`
+}
+
+func (e *Authorization) Router() chi.Router {
+	r := chi.NewRouter()
+	r.Post("/", e.post)
+
+	return r
+}
+
+// @Summary Determine whether the specified action (call) is allowed or not.
+// @Accept json
+// @Produce json
+// @Param payload body AuthorizationRequest true "Action to be reviewed"
+// @Success 200 {object} bouncer.Response
+// @Failure 400
+// @Failure 500
+// @Tags bouncer
+// @Router /bouncer [post]
+func (e *Authorization) post(w http.ResponseWriter, r *http.Request) {
+	var payload AuthorizationRequest
+	decoder := json.NewDecoder(r.Body)
+	err := decoder.Decode(&payload)
+	if err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	response := e.Bouncer.Check(r.Context(), payload.From, payload.Extension)
+	content, err := json.Marshal(response)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	_, err = w.Write(content)
+	if err != nil {
+		slog.Error("Failed to write response", slog.String("path", r.URL.Path), slog.String("reason", err.Error()))
+	}
+	w.WriteHeader(http.StatusOK)
+}

queries.sql

@@ -28,13 +28,26 @@ DELETE FROM ps_auths WHERE id = $1;
 
 -- name: ListEndpoints :many
 SELECT
-    id, context, transport
+    pe.id, pe.context, ee.extension
 FROM
-    ps_endpoints
+    ps_endpoints pe
+LEFT JOIN
+    ery_extension ee
+ON ee.endpoint_id = pe.sid
 LIMIT $1;
 
 -- name: NewExtension :exec
 INSERT INTO ery_extension
     (endpoint_id, extension)
 VALUES
     ($1, $2);
+
+-- name: GetEndpointByExtension :one
+SELECT
+    ps_endpoints.id
+FROM
+    ps_endpoints
+INNER JOIN
+    ery_extension ee on ps_endpoints.sid = ee.endpoint_id
+WHERE
+    ee.extension = $1;