engine/ooapi: autogenerated API with login and caching (#234)

* internal/engine/ooapi: auto-generated API client

* feat: introduce the callers abstraction

* feat: implement API caching on disk

* feat: implement cloneWithToken when we require login

* feat: implement login

* fix: do not cache all APIs

* feat: start making space for more tests

* feat: implement caching policy

* feat: write tests for caching layer

* feat: add integration tests and fix some minor issues

* feat: write much more unit tests

* feat: add some more easy unit tests

* feat: add tests that use a local server

While there, make sure many fields we care about are OK.

* doc: write basic documentation

* fix: tweak sentence

* doc: improve ooapi documentation

* doc(ooapi): other documentation improvements

* fix(ooapi): remove caching for most APIs

We discussed this topic yesterday with @FedericoCeratto. The only
place where we want LRU caching is MeasurementMeta.

* feat(ooapi): improve handling of errors during login

This was also discussed yesterday with @FedericoCeratto

* fix(swaggerdiff_test.go): temporarily disable

Before I work on this, I need to tend onto other tasks.

* fix(ootest): add one more test case

We're going towards 100% coverage of this package, as it ought to be.

* feat(ooapi): test cases for when the probe clock is off

* fix(ooapi): change test to have 100% unittest coverage

* feat: sync server and client APIs definition

Companion PR: https://github.com/ooni/api/pull/218

* fix(ooapi): start testing again against API

* fix(ooapi): only generate each file once

* chore: set version to 3.7.0-alpha

While there, make sure we don't always skip a currently failing
riseupvpn test, and slightly clarify the readme.

* fix(kvstore): less scoped error message

internal/engine/ooapi/callers.go

@@ -0,0 +1,78 @@
+// Code generated by go generate; DO NOT EDIT.
+// 2021-02-26 15:45:51.773813223 +0100 CET m=+0.000114768
+
+package ooapi
+
+//go:generate go run ./internal/generator -file callers.go
+
+import (
+	"context"
+
+	"github.com/ooni/probe-cli/v3/internal/engine/ooapi/apimodel"
+)
+
+// CheckReportIDCaller represents any type exposing a method
+// like CheckReportIDAPI.Call.
+type CheckReportIDCaller interface {
+	Call(ctx context.Context, req *apimodel.CheckReportIDRequest) (*apimodel.CheckReportIDResponse, error)
+}
+
+// CheckInCaller represents any type exposing a method
+// like CheckInAPI.Call.
+type CheckInCaller interface {
+	Call(ctx context.Context, req *apimodel.CheckInRequest) (*apimodel.CheckInResponse, error)
+}
+
+// LoginCaller represents any type exposing a method
+// like LoginAPI.Call.
+type LoginCaller interface {
+	Call(ctx context.Context, req *apimodel.LoginRequest) (*apimodel.LoginResponse, error)
+}
+
+// MeasurementMetaCaller represents any type exposing a method
+// like MeasurementMetaAPI.Call.
+type MeasurementMetaCaller interface {
+	Call(ctx context.Context, req *apimodel.MeasurementMetaRequest) (*apimodel.MeasurementMetaResponse, error)
+}
+
+// RegisterCaller represents any type exposing a method
+// like RegisterAPI.Call.
+type RegisterCaller interface {
+	Call(ctx context.Context, req *apimodel.RegisterRequest) (*apimodel.RegisterResponse, error)
+}
+
+// TestHelpersCaller represents any type exposing a method
+// like TestHelpersAPI.Call.
+type TestHelpersCaller interface {
+	Call(ctx context.Context, req *apimodel.TestHelpersRequest) (apimodel.TestHelpersResponse, error)
+}
+
+// PsiphonConfigCaller represents any type exposing a method
+// like PsiphonConfigAPI.Call.
+type PsiphonConfigCaller interface {
+	Call(ctx context.Context, req *apimodel.PsiphonConfigRequest) (apimodel.PsiphonConfigResponse, error)
+}
+
+// TorTargetsCaller represents any type exposing a method
+// like TorTargetsAPI.Call.
+type TorTargetsCaller interface {
+	Call(ctx context.Context, req *apimodel.TorTargetsRequest) (apimodel.TorTargetsResponse, error)
+}
+
+// URLsCaller represents any type exposing a method
+// like URLsAPI.Call.
+type URLsCaller interface {
+	Call(ctx context.Context, req *apimodel.URLsRequest) (*apimodel.URLsResponse, error)
+}
+
+// OpenReportCaller represents any type exposing a method
+// like OpenReportAPI.Call.
+type OpenReportCaller interface {
+	Call(ctx context.Context, req *apimodel.OpenReportRequest) (*apimodel.OpenReportResponse, error)
+}
+
+// SubmitMeasurementCaller represents any type exposing a method
+// like SubmitMeasurementAPI.Call.
+type SubmitMeasurementCaller interface {
+	Call(ctx context.Context, req *apimodel.SubmitMeasurementRequest) (*apimodel.SubmitMeasurementResponse, error)
+}