feature_flags.go

/*
Copyright 2020 The Tekton Authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package config

import (
	"context"
	"fmt"
	"os"
	"strconv"
	"strings"

	corev1 "k8s.io/api/core/v1"
)

const (
	// StableAPIFields is the value used for "enable-api-fields" when only stable APIs should be usable.
	StableAPIFields = "stable"
	// AlphaAPIFields is the value used for "enable-api-fields" when alpha APIs should be usable as well.
	AlphaAPIFields = "alpha"
	// FullEmbeddedStatus is the value used for "embedded-status" when the full statuses of TaskRuns and Runs should be
	// embedded in PipelineRunStatusFields, but ChildReferences should not be used.
	FullEmbeddedStatus = "full"
	// BothEmbeddedStatus is the value used for "embedded-status" when full embedded statuses of TaskRuns and Runs as
	// well as ChildReferences should be used in PipelineRunStatusFields.
	BothEmbeddedStatus = "both"
	// MinimalEmbeddedStatus is the value used for "embedded-status" when only ChildReferences should be used in
	// PipelineRunStatusFields.
	MinimalEmbeddedStatus = "minimal"
	// DefaultDisableAffinityAssistant is the default value for "disable-affinity-assistant".
	DefaultDisableAffinityAssistant = false
	// DefaultDisableCredsInit is the default value for "disable-creds-init".
	DefaultDisableCredsInit = false
	// DefaultRunningInEnvWithInjectedSidecars is the default value for "running-in-environment-with-injected-sidecars".
	DefaultRunningInEnvWithInjectedSidecars = true
	// DefaultAwaitSidecarReadiness is the default value for "await-sidecar-readiness".
	DefaultAwaitSidecarReadiness = true
	// DefaultRequireGitSSHSecretKnownHosts is the default value for "require-git-ssh-secret-known-hosts".
	DefaultRequireGitSSHSecretKnownHosts = false
	// DefaultEnableTektonOciBundles is the default value for "enable-tekton-oci-bundles".
	DefaultEnableTektonOciBundles = false
	// DefaultEnableCustomTasks is the default value for "enable-custom-tasks".
	DefaultEnableCustomTasks = false
	// DefaultEnableAPIFields is the default value for "enable-api-fields".
	DefaultEnableAPIFields = StableAPIFields
	// DefaultSendCloudEventsForRuns is the default value for "send-cloudevents-for-runs".
	DefaultSendCloudEventsForRuns = false
	// DefaultEmbeddedStatus is the default value for "embedded-status".
	DefaultEmbeddedStatus = FullEmbeddedStatus

	disableAffinityAssistantKey         = "disable-affinity-assistant"
	disableCredsInitKey                 = "disable-creds-init"
	runningInEnvWithInjectedSidecarsKey = "running-in-environment-with-injected-sidecars"
	awaitSidecarReadinessKey            = "await-sidecar-readiness"
	requireGitSSHSecretKnownHostsKey    = "require-git-ssh-secret-known-hosts" // nolint: gosec
	enableTektonOCIBundles              = "enable-tekton-oci-bundles"
	enableCustomTasks                   = "enable-custom-tasks"
	enableAPIFields                     = "enable-api-fields"
	sendCloudEventsForRuns              = "send-cloudevents-for-runs"
	embeddedStatus                      = "embedded-status"
)

// FeatureFlags holds the features configurations
// +k8s:deepcopy-gen=true
type FeatureFlags struct {
	DisableAffinityAssistant         bool
	DisableCredsInit                 bool
	RunningInEnvWithInjectedSidecars bool
	RequireGitSSHSecretKnownHosts    bool
	EnableTektonOCIBundles           bool
	EnableCustomTasks                bool
	ScopeWhenExpressionsToTask       bool
	EnableAPIFields                  string
	SendCloudEventsForRuns           bool
	AwaitSidecarReadiness            bool
	EmbeddedStatus                   string
}

// GetFeatureFlagsConfigName returns the name of the configmap containing all
// feature flags.
func GetFeatureFlagsConfigName() string {
	if e := os.Getenv("CONFIG_FEATURE_FLAGS_NAME"); e != "" {
		return e
	}
	return "feature-flags"
}

// NewFeatureFlagsFromMap returns a Config given a map corresponding to a ConfigMap
func NewFeatureFlagsFromMap(cfgMap map[string]string) (*FeatureFlags, error) {
	setFeature := func(key string, defaultValue bool, feature *bool) error {
		if cfg, ok := cfgMap[key]; ok {
			value, err := strconv.ParseBool(cfg)
			if err != nil {
				return fmt.Errorf("failed parsing feature flags config %q: %v", cfg, err)
			}
			*feature = value
			return nil
		}
		*feature = defaultValue
		return nil
	}

	tc := FeatureFlags{}
	if err := setFeature(disableAffinityAssistantKey, DefaultDisableAffinityAssistant, &tc.DisableAffinityAssistant); err != nil {
		return nil, err
	}
	if err := setFeature(disableCredsInitKey, DefaultDisableCredsInit, &tc.DisableCredsInit); err != nil {
		return nil, err
	}
	if err := setFeature(runningInEnvWithInjectedSidecarsKey, DefaultRunningInEnvWithInjectedSidecars, &tc.RunningInEnvWithInjectedSidecars); err != nil {
		return nil, err
	}
	if err := setFeature(awaitSidecarReadinessKey, DefaultAwaitSidecarReadiness, &tc.AwaitSidecarReadiness); err != nil {
		return nil, err
	}
	if err := setFeature(requireGitSSHSecretKnownHostsKey, DefaultRequireGitSSHSecretKnownHosts, &tc.RequireGitSSHSecretKnownHosts); err != nil {
		return nil, err
	}
	if err := setEnabledAPIFields(cfgMap, DefaultEnableAPIFields, &tc.EnableAPIFields); err != nil {
		return nil, err
	}
	if err := setFeature(sendCloudEventsForRuns, DefaultSendCloudEventsForRuns, &tc.SendCloudEventsForRuns); err != nil {
		return nil, err
	}
	if err := setEmbeddedStatus(cfgMap, DefaultEmbeddedStatus, &tc.EmbeddedStatus); err != nil {
		return nil, err
	}

	// Given that they are alpha features, Tekton Bundles and Custom Tasks should be switched on if
	// enable-api-fields is "alpha". If enable-api-fields is not "alpha" then fall back to the value of
	// each feature's individual flag.
	//
	// Note: the user cannot enable "alpha" while disabling bundles or custom tasks - that would
	// defeat the purpose of having a single shared gate for all alpha features.
	if tc.EnableAPIFields == AlphaAPIFields {
		tc.EnableTektonOCIBundles = true
		tc.EnableCustomTasks = true
	} else {
		if err := setFeature(enableTektonOCIBundles, DefaultEnableTektonOciBundles, &tc.EnableTektonOCIBundles); err != nil {
			return nil, err
		}
		if err := setFeature(enableCustomTasks, DefaultEnableCustomTasks, &tc.EnableCustomTasks); err != nil {
			return nil, err
		}
	}
	return &tc, nil
}

// setEnabledAPIFields sets the "enable-api-fields" flag based on the content of a given map.
// If the feature gate is invalid or missing then an error is returned.
func setEnabledAPIFields(cfgMap map[string]string, defaultValue string, feature *string) error {
	value := defaultValue
	if cfg, ok := cfgMap[enableAPIFields]; ok {
		value = strings.ToLower(cfg)
	}
	switch value {
	case AlphaAPIFields, StableAPIFields:
		*feature = value
	default:
		return fmt.Errorf("invalid value for feature flag %q: %q", enableAPIFields, value)
	}
	return nil
}

// setEmbeddedStatus sets the "embedded-status" flag based on the content of a given map.
// If the feature gate is invalid or missing then an error is returned.
func setEmbeddedStatus(cfgMap map[string]string, defaultValue string, feature *string) error {
	value := defaultValue
	if cfg, ok := cfgMap[embeddedStatus]; ok {
		value = strings.ToLower(cfg)
	}
	switch value {
	case FullEmbeddedStatus, BothEmbeddedStatus, MinimalEmbeddedStatus:
		*feature = value
	default:
		return fmt.Errorf("invalid value for feature flag %q: %q", embeddedStatus, value)
	}
	return nil
}

// NewFeatureFlagsFromConfigMap returns a Config for the given configmap
func NewFeatureFlagsFromConfigMap(config *corev1.ConfigMap) (*FeatureFlags, error) {
	return NewFeatureFlagsFromMap(config.Data)
}

// EnableAlphaAPIFields enables alpha feature in an existing context (for use in testing)
func EnableAlphaAPIFields(ctx context.Context) context.Context {
	featureFlags, _ := NewFeatureFlagsFromMap(map[string]string{
		"enable-api-fields": "alpha",
	})
	cfg := &Config{
		Defaults: &Defaults{
			DefaultTimeoutMinutes: 60,
		},
		FeatureFlags: featureFlags,
	}
	return ToContext(ctx, cfg)
}