Feat/bazel (#34)

* add bazel

* Bump Chart version

* Update Bazel put

Author: KevinGruber2001

chart/Chart.yaml

@@ -5,7 +5,7 @@ description: A Gradle Build Cache server with Redis backend for Theia IDE deploy
 type: application
 
 # Chart version - bump for breaking changes
-version: 0.3.1
+version: 0.4.0
 
 # Application version - matches the cache server version
 appVersion: "0.1.0"

chart/templates/configmap.yaml

@@ -23,7 +23,8 @@ data:
       addr: "{{ .Release.Name }}-redis:6379"
 
     cache:
-      max_entry_size_mb: 100
+      max_entry_size_mb: {{ .Values.cache.maxEntrySizeMB }}
+      verify_cas_hash: {{ .Values.cache.verifyCASHash }}
 
     auth:
       enabled: {{ .Values.auth.enabled }}

chart/values.yaml

@@ -43,6 +43,13 @@ resources:
       memory: "2Gi"
       cpu: "1000m"
 
+# Cache settings (shared by Gradle and Bazel)
+cache:
+  # Maximum entry size in MB
+  maxEntrySizeMB: 100
+  # Verify SHA-256 hash of Bazel CAS blobs on PUT
+  verifyCASHash: true
+
 tls:
   # Enable TLS for the cache server
   enabled: false

src/configs/config.yaml

@@ -10,6 +10,7 @@ storage:
 
 cache:
   max_entry_size_mb: 100
+  verify_cas_hash: true
 
 auth:
   enabled: true

src/internal/config/config.go

@@ -39,6 +39,7 @@ type StorageConfig struct {
 
 type CacheConfig struct {
 	MaxEntrySizeMB int64 `mapstructure:"max_entry_size_mb"`
+	VerifyCASHash  bool  `mapstructure:"verify_cas_hash"`
 }
 
 type AuthConfig struct {
@@ -82,6 +83,7 @@ func Load(configPath string) (*Config, error) {
 	v.SetDefault("storage.db", 0)
 
 	v.SetDefault("cache.max_entry_size_mb", 100)
+	v.SetDefault("cache.verify_cas_hash", true)
 
 	v.SetDefault("auth.enabled", true)
 
@@ -146,3 +148,4 @@ func (c *Config) Validate() error {
 func (c *Config) MaxEntrySizeBytes() int64 {
 	return c.Cache.MaxEntrySizeMB * 1024 * 1024
 }
+

src/internal/handler/bazel_get.go

@@ -0,0 +1,47 @@
+package handler
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/kevingruber/gradle-cache/internal/storage"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+)
+
+// GetAC handles GET requests for Bazel action cache entries.
+func (h *BazelHandler) GetAC(c *gin.Context) {
+	h.get(c, h.acStorage, "ac")
+}
+
+// GetCAS handles GET requests for Bazel content-addressable storage entries.
+func (h *BazelHandler) GetCAS(c *gin.Context) {
+	h.get(c, h.casStorage, "cas")
+}
+
+func (h *BazelHandler) get(c *gin.Context, store storage.Storage, cacheType string) {
+	hash := c.Param("hash")
+	if !isValidSHA256Hex(hash) {
+		c.Status(http.StatusBadRequest)
+		return
+	}
+
+	attrs := metric.WithAttributes(attribute.String("cache_type", cacheType))
+
+	reader, size, err := store.Get(c.Request.Context(), hash)
+	if err != nil {
+		if errors.Is(err, storage.ErrNotFound) {
+			h.metrics.CacheMisses.Add(c.Request.Context(), 1, attrs)
+			c.Status(http.StatusNotFound)
+			return
+		}
+		h.logger.Error().Err(err).Str("hash", hash).Str("cache_type", cacheType).Msg("failed to get bazel cache entry")
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+	defer reader.Close()
+
+	h.metrics.CacheHits.Add(c.Request.Context(), 1, attrs)
+	c.DataFromReader(http.StatusOK, size, "application/octet-stream", reader, nil)
+}

src/internal/handler/bazel_handler.go

@@ -0,0 +1,35 @@
+package handler
+
+import (
+	"github.com/kevingruber/gradle-cache/internal/storage"
+	"github.com/rs/zerolog"
+)
+
+// BazelHandler handles Bazel HTTP remote cache requests.
+// Bazel uses two namespaces: /ac/ (action cache) and /cas/ (content-addressable storage).
+type BazelHandler struct {
+	acStorage    storage.Storage
+	casStorage   storage.Storage
+	maxEntrySize int64
+	verifyCAS    bool
+	logger       zerolog.Logger
+	metrics      *BazelMetrics
+}
+
+// NewBazelHandler creates a new Bazel cache handler.
+// The store must implement NamespacedStorage to isolate AC and CAS keys.
+func NewBazelHandler(store storage.NamespacedStorage, maxEntrySize int64, verifyCAS bool, logger zerolog.Logger) (*BazelHandler, error) {
+	metrics, err := NewBazelMetrics()
+	if err != nil {
+		return nil, err
+	}
+
+	return &BazelHandler{
+		acStorage:    store.WithNamespace("bazel:ac"),
+		casStorage:   store.WithNamespace("bazel:cas"),
+		maxEntrySize: maxEntrySize,
+		verifyCAS:    verifyCAS,
+		logger:       logger,
+		metrics:      metrics,
+	}, nil
+}

src/internal/handler/bazel_metrics.go

@@ -0,0 +1,52 @@
+package handler
+
+import (
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/metric"
+)
+
+type BazelMetrics struct {
+	CacheHits      metric.Int64Counter
+	CacheMisses    metric.Int64Counter
+	HashMismatches metric.Int64Counter
+	EntrySize      metric.Float64Histogram
+}
+
+func NewBazelMetrics() (*BazelMetrics, error) {
+	meter := otel.Meter("bazel-cache")
+
+	cacheHits, err := meter.Int64Counter(
+		"bazel_cache.cache_hits",
+		metric.WithDescription("Total number of Bazel cache hits"))
+	if err != nil {
+		return nil, err
+	}
+
+	cacheMisses, err := meter.Int64Counter(
+		"bazel_cache.cache_misses",
+		metric.WithDescription("Total number of Bazel cache misses"))
+	if err != nil {
+		return nil, err
+	}
+
+	hashMismatches, err := meter.Int64Counter(
+		"bazel_cache.hash_mismatches",
+		metric.WithDescription("Total number of CAS hash verification failures"))
+	if err != nil {
+		return nil, err
+	}
+
+	entrySize, err := meter.Float64Histogram(
+		"bazel_cache.entry_size",
+		metric.WithDescription("Size of Bazel cache entries in bytes"))
+	if err != nil {
+		return nil, err
+	}
+
+	return &BazelMetrics{
+		CacheHits:      cacheHits,
+		CacheMisses:    cacheMisses,
+		HashMismatches: hashMismatches,
+		EntrySize:      entrySize,
+	}, nil
+}

src/internal/handler/bazel_put.go

@@ -0,0 +1,177 @@
+package handler
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+
+	"github.com/gin-gonic/gin"
+	"github.com/kevingruber/gradle-cache/internal/storage"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+)
+
+// PutAC handles PUT requests to store Bazel action cache entries.
+func (h *BazelHandler) PutAC(c *gin.Context) {
+	h.put(c, h.acStorage, "ac", false)
+}
+
+// PutCAS handles PUT requests to store Bazel CAS entries.
+// If verifyCAS is enabled, the content hash is verified against the URL hash.
+func (h *BazelHandler) PutCAS(c *gin.Context) {
+	h.put(c, h.casStorage, "cas", h.verifyCAS)
+}
+
+func (h *BazelHandler) put(c *gin.Context, store storage.Storage, cacheType string, verifyHash bool) {
+	hash := c.Param("hash")
+	if !isValidSHA256Hex(hash) {
+		c.Status(http.StatusBadRequest)
+		return
+	}
+
+	attrs := metric.WithAttributes(attribute.String("cache_type", cacheType))
+
+	// Early rejection if Content-Length is known and too large
+	contentLength := c.Request.ContentLength
+	if contentLength > h.maxEntrySize {
+		h.logger.Warn().
+			Str("hash", hash).
+			Str("cache_type", cacheType).
+			Int64("size", contentLength).
+			Int64("max_size", h.maxEntrySize).
+			Msg("bazel cache entry too large")
+		c.Status(http.StatusRequestEntityTooLarge)
+		return
+	}
+
+	if verifyHash {
+		h.putWithVerify(c, store, hash, cacheType, attrs)
+	} else {
+		h.putDirect(c, store, hash, cacheType, contentLength, attrs)
+	}
+}
+
+// putDirect streams the request body to storage without hash verification.
+// If Content-Length is known, streams directly. Otherwise spools to a temp file.
+func (h *BazelHandler) putDirect(c *gin.Context, store storage.Storage, hash, cacheType string, contentLength int64, attrs metric.MeasurementOption) {
+	if contentLength >= 0 {
+		// Content-Length known: stream directly to storage
+		limited := io.LimitReader(c.Request.Body, contentLength)
+		h.metrics.EntrySize.Record(c.Request.Context(), float64(contentLength), attrs)
+
+		if err := store.Put(c.Request.Context(), hash, limited, contentLength); err != nil {
+			h.logger.Error().Err(err).Str("hash", hash).Str("cache_type", cacheType).Msg("failed to store bazel cache entry")
+			c.Status(http.StatusInternalServerError)
+			return
+		}
+		c.Status(http.StatusOK)
+		return
+	}
+
+	// Chunked transfer: spool to temp file to determine size
+	size, reader, cleanup, err := h.spoolToTempFile(c.Request.Body)
+	if cleanup != nil {
+		defer cleanup()
+	}
+	if err != nil {
+		h.logger.Error().Err(err).Str("hash", hash).Str("cache_type", cacheType).Msg("failed to read request body")
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+	if size > h.maxEntrySize {
+		c.Status(http.StatusRequestEntityTooLarge)
+		return
+	}
+
+	h.metrics.EntrySize.Record(c.Request.Context(), float64(size), attrs)
+
+	if err := store.Put(c.Request.Context(), hash, reader, size); err != nil {
+		h.logger.Error().Err(err).Str("hash", hash).Str("cache_type", cacheType).Msg("failed to store bazel cache entry")
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+	c.Status(http.StatusOK)
+}
+
+// putWithVerify spools the upload to a temp file while computing the SHA-256 hash,
+// then verifies the hash before storing.
+func (h *BazelHandler) putWithVerify(c *gin.Context, store storage.Storage, hash, cacheType string, attrs metric.MeasurementOption) {
+	f, err := os.CreateTemp("", "bazel-cas-*")
+	if err != nil {
+		h.logger.Error().Err(err).Msg("failed to create temp file for CAS verification")
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+	defer os.Remove(f.Name())
+	defer f.Close()
+
+	hasher := sha256.New()
+	limited := io.LimitReader(c.Request.Body, h.maxEntrySize+1)
+	tee := io.TeeReader(limited, hasher)
+
+	written, err := io.Copy(f, tee)
+	if err != nil {
+		h.logger.Error().Err(err).Str("hash", hash).Str("cache_type", cacheType).Msg("failed to read request body")
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+
+	if written > h.maxEntrySize {
+		c.Status(http.StatusRequestEntityTooLarge)
+		return
+	}
+
+	computedHex := hex.EncodeToString(hasher.Sum(nil))
+	if computedHex != hash {
+		h.metrics.HashMismatches.Add(c.Request.Context(), 1, attrs)
+		h.logger.Warn().
+			Str("expected", hash).
+			Str("computed", computedHex).
+			Msg("bazel CAS hash mismatch")
+		c.Status(http.StatusBadRequest)
+		return
+	}
+
+	if _, err := f.Seek(0, io.SeekStart); err != nil {
+		h.logger.Error().Err(err).Msg("failed to seek temp file")
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+
+	h.metrics.EntrySize.Record(c.Request.Context(), float64(written), attrs)
+
+	if err := store.Put(c.Request.Context(), hash, f, written); err != nil {
+		h.logger.Error().Err(err).Str("hash", hash).Str("cache_type", cacheType).Msg("failed to store bazel cache entry")
+		c.Status(http.StatusInternalServerError)
+		return
+	}
+	c.Status(http.StatusOK)
+}
+
+// spoolToTempFile copies from r (limited to maxEntrySize+1) into a temp file
+// and returns the written size, a reader seeked to start, and a cleanup function.
+func (h *BazelHandler) spoolToTempFile(r io.Reader) (int64, io.Reader, func(), error) {
+	f, err := os.CreateTemp("", "bazel-spool-*")
+	if err != nil {
+		return 0, nil, nil, fmt.Errorf("create temp file: %w", err)
+	}
+	cleanup := func() {
+		f.Close()
+		os.Remove(f.Name())
+	}
+
+	limited := io.LimitReader(r, h.maxEntrySize+1)
+	written, err := io.Copy(f, limited)
+	if err != nil {
+		return 0, nil, cleanup, fmt.Errorf("spool to temp file: %w", err)
+	}
+
+	if _, err := f.Seek(0, io.SeekStart); err != nil {
+		return 0, nil, cleanup, fmt.Errorf("seek temp file: %w", err)
+	}
+
+	return written, f, cleanup, nil
+}

src/internal/handler/validation.go

@@ -0,0 +1,14 @@
+package handler
+
+// isValidSHA256Hex returns true if s is a valid lowercase hex-encoded SHA-256 hash (64 characters).
+func isValidSHA256Hex(s string) bool {
+	if len(s) != 64 {
+		return false
+	}
+	for _, c := range s {
+		if !((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f')) {
+			return false
+		}
+	}
+	return true
+}