feat(state): introduce cache e.g. to skip GitHub API requests for the same version information over and over again

internal/cmd/app.go

@@ -220,7 +220,11 @@ func (a *App) initBasic(ctx context.Context) (err error) {
 		return err
 	}
 
-	return a.Collection.With(services.WithVault(v), services.WithStateStore(s))
+	return a.Collection.With(
+		services.WithVault(v),
+		services.WithStateStore(s),
+		services.WithCache(state.NewStateCache(a.appCfg.Cache.TTL, s)),
+	)
 }
 
 func (a *App) RunModule(ctx context.Context, cat modules.Category, name string) error {

internal/parsing/context.go

@@ -29,7 +29,7 @@ func MockContext() *hcl.EvalContext {
 	string_helpers.RegisterInContext(evalctx)
 	hclhelpers.RegisterInContext(evalctx)
 	vaultHelpers.RegisterInContext(evalctx, vaultHelpers.MockGetter("<mocked>"))
-	github.RegisterInContext(context.Background(), evalctx, nil)
+	github.RegisterInContext(context.Background(), evalctx, nil, nil)
 
 	return evalctx
 }
@@ -65,7 +65,7 @@ func FullContext(ctx context.Context, parent *hcl.EvalContext, svc *services.Col
 		evalctx.Variables = make(map[string]cty.Value)
 	}
 
-	github.RegisterInContext(ctx, evalctx, svc.GitHubClient())
+	github.RegisterInContext(ctx, evalctx, svc.GitHubClient(), svc.Cache())
 
 	return evalctx
 }

internal/services/collection.go

@@ -52,6 +52,13 @@ func WithStateStore(store state.Store) CollectionOption {
 	})
 }
 
+func WithCache(cache state.Cache) CollectionOption {
+	return collectionOptionFunc(func(svc *Collection) error {
+		svc.cache = cache
+		return nil
+	})
+}
+
 func WithDockerClientFromEnv(ctx context.Context) CollectionOption {
 	return collectionOptionFunc(func(svc *Collection) error {
 		cli, err := client.NewClientWithOpts(
@@ -100,6 +107,7 @@ type Collection struct {
 	dockerClient *client.Client
 	ignorer      *ignore.Ignorer
 	stateStore   state.Store
+	cache        state.Cache
 }
 
 func (c *Collection) With(opts ...CollectionOption) error {
@@ -116,6 +124,10 @@ func (c *Collection) StateStore() state.Store {
 	return c.stateStore
 }
 
+func (c *Collection) Cache() state.Cache {
+	return c.cache
+}
+
 func (c *Collection) GitHubClient() *gh.Client {
 	return c.ghClient
 }

modules/helpers/github/get_release_info.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"time"
 
+	"code.icb4dc0.de/buildr/buildr/modules/state"
+
 	"github.com/google/go-github/v50/github"
 	"github.com/zclconf/go-cty/cty"
 	"github.com/zclconf/go-cty/cty/function"
@@ -11,7 +13,7 @@ import (
 
 const DefaultAPITimeout = 30 * time.Second
 
-func GetLatestReleaseTag(ctx context.Context, cli *github.Client) function.Function {
+func GetLatestReleaseTag(ctx context.Context, cli *github.Client, cache state.Cache) function.Function {
 	return function.New(&function.Spec{
 		Description: "Get tag of latest release of Github project",
 		Params: []function.Parameter{
@@ -31,6 +33,15 @@ func GetLatestReleaseTag(ctx context.Context, cli *github.Client) function.Funct
 			owner := args[0].AsString()
 			repo := args[1].AsString()
 
+			cacheKey := state.KeyOfStrings("latest_github_release", owner, repo)
+
+			if cache != nil {
+				val, _, err := cache.Get(ctx, cacheKey)
+				if err == nil && len(val) > 0 {
+					return cty.StringVal(string(val)), nil
+				}
+			}
+
 			if cli == nil {
 				return cty.StringVal("<mocked>"), nil
 			}
@@ -43,6 +54,8 @@ func GetLatestReleaseTag(ctx context.Context, cli *github.Client) function.Funct
 				return cty.Value{}, err
 			}
 
+			_ = cache.Set(ctx, cacheKey, []byte(release.GetTagName()))
+
 			return cty.StringVal(release.GetTagName()), nil
 		},
 	})

modules/helpers/github/registration.go

@@ -3,10 +3,12 @@ package github
 import (
 	"context"
 
+	"code.icb4dc0.de/buildr/buildr/modules/state"
+
 	"github.com/google/go-github/v50/github"
 	"github.com/hashicorp/hcl/v2"
 )
 
-func RegisterInContext(ctx context.Context, evalCtx *hcl.EvalContext, cli *github.Client) {
-	evalCtx.Functions["gh_latest_release"] = GetLatestReleaseTag(ctx, cli)
+func RegisterInContext(ctx context.Context, evalCtx *hcl.EvalContext, cli *github.Client, cache state.Cache) {
+	evalCtx.Functions["gh_latest_release"] = GetLatestReleaseTag(ctx, cli, cache)
 }

modules/state/api.go

@@ -32,3 +32,12 @@ type StoreWriter interface {
 type StoreReader interface {
 	Get(ctx context.Context, key Key) (state []byte, meta Metadata, err error)
 }
+
+type CacheWriter interface {
+	Set(ctx context.Context, key Key, state []byte) error
+}
+
+type Cache interface {
+	CacheWriter
+	StoreReader
+}

modules/state/options.go

@@ -12,12 +12,8 @@ func (f EntryOptionFunc) applyToEntry(e *ent.KVEntryCreate) {
 	f(e)
 }
 
-func WithTTL(t time.Time) EntryOption {
+func WithTTL(ttl time.Duration) EntryOption {
 	return EntryOptionFunc(func(e *ent.KVEntryCreate) {
-		if t.Location() != time.UTC {
-			t = t.UTC()
-		}
-
-		e.SetTTL(t)
+		e.SetTTL(time.Now().UTC().Add(ttl))
 	})
 }

modules/state/state_cache.go

@@ -0,0 +1,31 @@
+package state
+
+import (
+	"context"
+	"time"
+)
+
+func NewStateCache(ttl time.Duration, store Store) *StateCache {
+	return &StateCache{
+		TTL:   ttl,
+		Store: store,
+	}
+}
+
+var _ Cache = (*StateCache)(nil)
+
+type StateCache struct {
+	TTL   time.Duration
+	Store Store
+}
+
+func (s *StateCache) Set(ctx context.Context, key Key, state []byte) error {
+	return s.Store.Set(ctx, key, state, WithTTL(s.TTL))
+}
+
+func (s *StateCache) Get(ctx context.Context, key Key) (state []byte, meta Metadata, err error) {
+	if s == nil {
+		return nil, Metadata{}, nil
+	}
+	return s.Store.Get(ctx, key)
+}

modules/state/store.go

@@ -28,7 +28,7 @@ func NewEntStore(ctx context.Context, stateFilePath string) (*EntStore, error) {
 
 	_, err = client.KVEntry.
 		Delete().
-		Where(kventry.TTLGT(time.Now().UTC())).
+		Where(kventry.TTLLTE(time.Now().UTC())).
 		Exec(ctx)
 
 	if err != nil {
@@ -63,7 +63,7 @@ func (s *EntStore) Get(ctx context.Context, key Key) (state []byte, meta Metadat
 		return nil, Metadata{}, err
 	}
 
-	if kvEntry.TTL != nil && kvEntry.TTL.After(time.Now().UTC()) {
+	if kvEntry.TTL != nil && kvEntry.TTL.Before(time.Now().UTC()) {
 		return nil, Metadata{}, nil
 	}