feat: Implement appconfig package

go.mod

@@ -44,6 +44,7 @@ require (
 	github.com/mitchellh/hashstructure/v2 v2.0.2
 	github.com/oauth2-proxy/mockoidc v0.0.0-20240214162133-caebfff84d25
 	github.com/oauth2-proxy/oauth2-proxy/v7 v7.5.1
+	github.com/pquerna/cachecontrol v0.0.0-20171018203845-0dec1b30a021
 	github.com/prometheus/client_golang v1.18.0
 	github.com/relvacode/iso8601 v1.4.0
 	github.com/santhosh-tekuri/jsonschema/v5 v5.3.1

go.sum

@@ -1902,6 +1902,7 @@ github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRI
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/posener/complete v1.1.1/go.mod h1:em0nMJCgc9GFtwrmVmEMR/ZL6WyhyjMBndrE9hABlRI=
 github.com/posener/complete v1.2.3/go.mod h1:WZIdtGGp+qx0sLrYKtIRAruyNpv6hFCicSgv7Sy7s/s=
+github.com/pquerna/cachecontrol v0.0.0-20171018203845-0dec1b30a021 h1:0XM1XL/OFFJjXsYXlG30spTkV/E9+gmd5GD1w2HE8xM=
 github.com/pquerna/cachecontrol v0.0.0-20171018203845-0dec1b30a021/go.mod h1:prYjPmNq4d1NPVmpShWobRqXY3q7Vp+80DqgxxUrUIA=
 github.com/prashantv/gostub v1.1.0/go.mod h1:A5zLQHz7ieHGG7is6LLXLz7I8+3LZzsrV0P1IAHhP5U=
 github.com/prometheus/alertmanager v0.24.0/go.mod h1:r6fy/D7FRuZh5YbnX6J3MBY0eI4Pb5yPYS7/bPSXXqI=

internal/pkg/service/appproxy/appconfig/api.go

@@ -0,0 +1,122 @@
+package appconfig
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/keboola/go-client/pkg/request"
+	"github.com/pquerna/cachecontrol/cacheobject"
+)
+
+type AppProxyConfig struct {
+	ID              string         `json:"id"`
+	Name            string         `json:"name"`
+	UpstreamAppHost string         `json:"upstreamAppHost"`
+	AuthProviders   []AuthProvider `json:"authProviders"`
+	AuthRules       []AuthRule     `json:"authRules"`
+	eTag            string
+	maxAge          time.Duration
+}
+
+type AuthProvider struct {
+	ID           string   `json:"id"`
+	Name         string   `json:"name"`
+	Type         string   `json:"type"`
+	ClientID     string   `json:"clientId"`
+	ClientSecret string   `json:"clientSecret"`
+	IssuerURL    string   `json:"issuerUrl"`
+	AllowedRoles []string `json:"allowedRoles"`
+}
+
+type AuthRule struct {
+	Type  string   `json:"type"`
+	Value string   `json:"value"`
+	Auth  []string `json:"auth"`
+}
+
+func GetAppProxyConfig(sender request.Sender, appID string, eTag string) request.APIRequest[*AppProxyConfig] {
+	result := &AppProxyConfig{}
+	req := request.NewHTTPRequest(sender).
+		WithError(&SandboxesError{}).
+		WithResult(result).
+		WithGet("apps/{appId}/proxy-config").
+		AndPathParam("appId", appID).
+		AndHeader("If-None-Match", eTag).
+		WithOnSuccess(func(ctx context.Context, response request.HTTPResponse) error {
+			// Use id as fallback until name is added to Sandboxes API
+			if result.Name == "" {
+				result.Name = result.ID
+			}
+			for i, provider := range result.AuthProviders {
+				if provider.Name == "" {
+					result.AuthProviders[i].Name = provider.ID
+				}
+			}
+
+			// Add ETag to result
+			result.eTag = response.ResponseHeader().Get("ETag")
+
+			// Process Cache-Control header
+			cacheControl := response.ResponseHeader().Get("Cache-Control")
+			if cacheControl == "" {
+				return nil
+			}
+
+			cacheDirectives, err := cacheobject.ParseResponseCacheControl(cacheControl)
+			if err != nil {
+				return err
+			}
+
+			if cacheDirectives.NoStore || cacheDirectives.NoCache != nil {
+				return nil
+			}
+
+			result.maxAge = time.Second * time.Duration(cacheDirectives.MaxAge)
+			return nil
+		})
+	return request.NewAPIRequest(result, req)
+}
+
+// SandboxesError represents the structure of API error.
+type SandboxesError struct {
+	Message     string `json:"error"`
+	ExceptionID string `json:"exceptionId"`
+	request     *http.Request
+	response    *http.Response
+}
+
+func (e *SandboxesError) Error() string {
+	return fmt.Sprintf("sandboxes api error[%d]: %s", e.StatusCode(), e.Message)
+}
+
+// ErrorName returns a human-readable name of the error.
+func (e *SandboxesError) ErrorName() string {
+	return http.StatusText(e.StatusCode())
+}
+
+// ErrorUserMessage returns error message for end user.
+func (e *SandboxesError) ErrorUserMessage() string {
+	return e.Message
+}
+
+// ErrorExceptionID returns exception ID to find details in logs.
+func (e *SandboxesError) ErrorExceptionID() string {
+	return e.ExceptionID
+}
+
+// StatusCode returns HTTP status code.
+func (e *SandboxesError) StatusCode() int {
+	return e.response.StatusCode
+}
+
+// SetRequest method allows injection of HTTP request to the error, it implements client.errorWithRequest.
+func (e *SandboxesError) SetRequest(request *http.Request) {
+	e.request = request
+}
+
+// SetResponse method allows injection of HTTP response to the error, it implements client.errorWithResponse.
+func (e *SandboxesError) SetResponse(response *http.Response) {
+	e.response = response
+}

internal/pkg/service/appproxy/appconfig/appconfig.go

@@ -0,0 +1,106 @@
+package appconfig
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/benbjohnson/clock"
+	"github.com/keboola/go-client/pkg/client"
+	"github.com/keboola/go-client/pkg/request"
+	"go.opentelemetry.io/otel/attribute"
+
+	"github.com/keboola/keboola-as-code/internal/pkg/log"
+	"github.com/keboola/keboola-as-code/internal/pkg/utils/errors"
+)
+
+type Loader struct {
+	logger log.Logger
+	clock  clock.Clock
+	sender request.Sender
+	cache  map[string]cacheItem
+}
+
+type cacheItem struct {
+	config    AppProxyConfig
+	eTag      string
+	expiresAt time.Time
+}
+
+func NewLoader(logger log.Logger, clock clock.Clock, baseURL string) *Loader {
+	return &Loader{
+		logger: logger,
+		clock:  clock,
+		sender: client.New().WithBaseURL(baseURL),
+		cache:  make(map[string]cacheItem),
+	}
+}
+
+const staleCacheFallbackDuration = time.Hour
+
+func (l *Loader) LoadConfig(ctx context.Context, appID string) (AppProxyConfig, error) {
+	var config *AppProxyConfig
+	var err error
+	now := l.clock.Now()
+
+	if item, ok := l.cache[appID]; ok {
+		// Return config from cache if still valid
+		if now.Before(item.expiresAt) {
+			return item.config, nil
+		}
+
+		// API request with cached ETag
+		config, err = GetAppProxyConfig(l.sender, appID, item.eTag).Send(ctx)
+		if err != nil {
+			return l.handleError(ctx, appID, now, err, &item)
+		}
+
+		// Update expiration and use the cached config if ETag is still the same
+		if config.eTag == item.eTag {
+			l.cache[appID] = cacheItem{
+				config:    item.config,
+				eTag:      item.eTag,
+				expiresAt: now.Add(config.maxAge),
+			}
+			return item.config, nil
+		}
+	} else {
+		// API request without ETag because cache is empty
+		config, err = GetAppProxyConfig(l.sender, appID, "").Send(ctx)
+		if err != nil {
+			return l.handleError(ctx, appID, now, err, nil)
+		}
+	}
+
+	// Save result to cache
+	l.cache[appID] = cacheItem{
+		config:    *config,
+		eTag:      config.eTag,
+		expiresAt: now.Add(config.maxAge),
+	}
+	return *config, nil
+}
+
+func (l *Loader) handleError(ctx context.Context, appID string, now time.Time, err error, fallbackItem *cacheItem) (AppProxyConfig, error) {
+	var sandboxesError *SandboxesError
+	errors.As(err, &sandboxesError)
+	if sandboxesError != nil && sandboxesError.StatusCode() == http.StatusNotFound {
+		return AppProxyConfig{}, err
+	}
+
+	logger := l.logger
+	if sandboxesError != nil {
+		logger = l.logger.With(attribute.String("exceptionId", sandboxesError.ExceptionID))
+	}
+
+	// An error other than 404 is considered a temporary failure. Keep using the stale cache for staleCacheFallbackDuration as fallback.
+	if fallbackItem != nil && now.Before(fallbackItem.expiresAt.Add(staleCacheFallbackDuration)) {
+		logger.Warnf(ctx, `Using stale cache for app "%s": %s`, appID, err.Error())
+
+		return fallbackItem.config, nil
+	}
+
+	logger.Errorf(ctx, `Failed loading config for app "%s": %s`, appID, err.Error())
+
+	return AppProxyConfig{}, err
+}