wip refactoring: better logging and error systems

internal/app/api/pkg/middleware/cleanup.go

@@ -0,0 +1,38 @@
+package middleware
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/resource"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
+)
+
+// Cleanup helps removing a resource at the end of a request.
+func Cleanup() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			const op = "middleware.Cleanup"
+			err := next(c)
+			ctx := context.MustCastFromEchoContext(c)
+			r := ctx.Resource()
+			if r == nil {
+				return err
+			}
+			// if a webhook URL has been given,
+			// do not remove the resource here because
+			// we don't know if the result file has been
+			// generated or sent.
+			if r.Has(resource.WebhookURLFormField) {
+				return err
+			}
+			// a resource is associated with our custom context.
+			if resourceErr := r.Close(); resourceErr != nil {
+				ctx.StandardLogger().ErrorOp(op, &standarderror.Error{
+					Op:  op,
+					Err: resourceErr,
+				})
+			}
+			return err
+		}
+	}
+}

internal/app/api/pkg/middleware/context.go

@@ -0,0 +1,41 @@
+package middleware
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/handler"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/config"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/logger"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/random"
+)
+
+// Context helps extending the default echo.Context with
+// our custom context.
+func Context(config *config.Config) echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			// generate a unique identifier for the request.
+			trace := random.Get()
+			// create the logger for this request using
+			// the previous identifier as trace.
+			logger := logger.New(config.LogLevel(), trace)
+			// extend the current echo context with our custom
+			// context.
+			ctx := context.New(c, logger, config)
+			// if its an healthcheck request, there
+			// is no resource associated to it.
+			if ctx.Path() == handler.PingEndpoint {
+				return next(ctx)
+			}
+			// if the endpoint is not for healthcheck, associate a
+			// resource to our custom context.
+			if err := ctx.WithResource(trace); err != nil {
+				// required to have a correct status code
+				// in the logs.
+				ctx.Error(err)
+				return ctx.LogRequestResult(err, false)
+			}
+			return next(ctx)
+		}
+	}
+}

internal/app/api/pkg/middleware/doc.go

@@ -0,0 +1,3 @@
+// Package middleware contains the
+// middleware of the API.
+package middleware

internal/app/api/pkg/middleware/error.go

@@ -0,0 +1,43 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/labstack/echo/v4"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/standarderror"
+)
+
+// Error helps handling errors (if any).
+func Error() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			ctx := context.MustCastFromEchoContext(c)
+			err := next(ctx)
+			if err == nil {
+				// so far so good!
+				return nil
+			}
+			// we log the initial error before returning
+			// the HTTP error.
+			logger := ctx.StandardLogger()
+			logger.Error(err.Error())
+			// handle our custom HTTP error.
+			var httpErr error
+			errCode := standarderror.Code(err)
+			errMessage := standarderror.Message(err)
+			switch errCode {
+			case standarderror.Invalid:
+				httpErr = echo.NewHTTPError(http.StatusBadRequest, errMessage)
+			case standarderror.Timeout:
+				httpErr = echo.NewHTTPError(http.StatusRequestTimeout, errMessage)
+			default:
+				httpErr = echo.NewHTTPError(http.StatusInternalServerError, errMessage)
+			}
+			// required to have a correct status code
+			// in the logs.
+			ctx.Error(httpErr)
+			return httpErr
+		}
+	}
+}

internal/app/api/pkg/middleware/logger.go

@@ -0,0 +1,21 @@
+package middleware
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/context"
+	"github.com/thecodingmachine/gotenberg/internal/app/api/pkg/handler"
+)
+
+// Logger helps logging the result of a request.
+func Logger() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			ctx := context.MustCastFromEchoContext(c)
+			err := next(ctx)
+			// we do not want to log healthcheck requests if
+			// log level is not set to DEBUG.
+			isDebug := ctx.Path() == handler.PingEndpoint
+			return ctx.LogRequestResult(err, isDebug)
+		}
+	}
+}