S3 support

README.md

@@ -40,3 +40,13 @@ $ GOCACHEPROG="$HOME/go/bin/go-cacher --verbose" go install std
 Defaulting to cache dir /home/bradfitz/.cache/go-cacher ...
 cacher: closing; 808 gets (808 hits, 0 misses, 0 errors); 0 puts (0 errors)
 ```
+
+## S3 Support
+We support S3 backend for caching.
+You can connect to S3 backend by setting the following parameters:
+- `GOCACHE_S3_BUCKET` - Name of S3 bucket
+- `GOCACHE_AWS_REGION` - AWS Region of bucket
+- `GOCACHE_AWS_ACCESS_KEY` + `GOCACHE_AWS_SECRET_KEY` / `GOCACHE_AWS_PROFILE` - Direct credentials or creds profile to use.
+- `GOCACHE_CACHE_KEY` - (Optional, default `v1`) Unique key
+
+The cache would be stored to `s3://<bucket>/cache/<cache_key>/<architecture>/<os>/<go-version>`

cachers/s3.go

@@ -0,0 +1,192 @@
+package cachers
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"runtime"
+	"strings"
+
+	"github.com/aws/smithy-go"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+)
+
+type S3Cache struct {
+	Bucket string
+	cfg    *aws.Config
+	// diskCache is where to write the output files to local disk, as required by the
+	// cache protocol.
+	diskCache *DiskCache
+
+	prefix string
+	// verbose optionally specifies whether to log verbose messages.
+	verbose bool
+
+	s3Client *s3.Client
+}
+
+func NewS3Cache(bucketName string, cfg *aws.Config, cacheKey string, disk *DiskCache, verbose bool) *S3Cache {
+	// get current architecture
+	arc := runtime.GOARCH
+	// get current operating system
+	os := runtime.GOOS
+	// get current version of Go
+	ver := strings.ReplaceAll(strings.ReplaceAll(runtime.Version(), " ", "-"), ":", "-")
+	prefix := fmt.Sprintf("cache/%s/%s/%s/%s", cacheKey, arc, os, ver)
+	log.Printf("S3Cache: configured to s3://%s/%s", bucketName, prefix)
+	return &S3Cache{
+		Bucket:    bucketName,
+		cfg:       cfg,
+		diskCache: disk,
+		prefix:    prefix,
+		verbose:   verbose,
+	}
+}
+
+func (c *S3Cache) client(ctx context.Context) (*s3.Client, error) {
+	if c.s3Client != nil {
+		return c.s3Client, nil
+	}
+	c.s3Client = s3.NewFromConfig(*c.cfg)
+	return c.s3Client, nil
+}
+
+func isNotFoundError(err error) bool {
+	if err != nil {
+		var ae smithy.APIError
+		if errors.As(err, &ae) {
+			code := ae.ErrorCode()
+			return code == "AccessDenied" || code == "NoSuchKey"
+		}
+	}
+	return false
+}
+
+func (c *S3Cache) Get(ctx context.Context, actionID string) (outputID, diskPath string, err error) {
+	outputID, diskPath, err = c.diskCache.Get(ctx, actionID)
+	if err == nil && outputID != "" {
+		return outputID, diskPath, nil
+	}
+	client, err := c.client(ctx)
+	if err != nil {
+		if c.verbose {
+			log.Printf("error getting S3 client: %v", err)
+		}
+		return "", "", err
+	}
+	actionKey := c.actionKey(actionID)
+	result, err := client.GetObject(ctx, &s3.GetObjectInput{
+		Bucket: &c.Bucket,
+		Key:    &actionKey,
+	})
+	// handle object not found
+	if isNotFoundError(err) {
+		return "", "", nil
+	} else if err != nil {
+		if c.verbose {
+			log.Printf("error S3 get for %s:  %v", actionKey, err)
+		}
+		return "", "", fmt.Errorf("unexpected S3 get for %s:  %v", actionKey, err)
+	}
+	defer result.Body.Close()
+	var av ActionValue
+	body, err := io.ReadAll(result.Body)
+	if err != nil {
+		return "", "", err
+	}
+	if err := json.Unmarshal(body, &av); err != nil {
+		if c.verbose {
+			log.Printf("error unmarshalling JSON for %s:  %v", actionKey, err)
+		}
+		return "", "", err
+	}
+
+	outputID = av.OutputID
+
+	var putBody io.Reader
+	if av.Size == 0 {
+		putBody = bytes.NewReader(nil)
+	} else {
+		outputKey := c.outputKey(outputID)
+		outputResult, getOutputErr := client.GetObject(ctx, &s3.GetObjectInput{
+			Bucket: &c.Bucket,
+			Key:    &outputKey,
+		})
+		if isNotFoundError(getOutputErr) {
+			// handle object not found
+			return "", "", nil
+		} else if getOutputErr != nil {
+			if c.verbose {
+				log.Printf("error S3 get for %s:  %v", outputKey, getOutputErr)
+			}
+			return "", "", fmt.Errorf("unexpected S3 get for %s:  %v", outputKey, getOutputErr)
+		}
+		defer outputResult.Body.Close()
+
+		putBody = outputResult.Body
+	}
+	diskPath, err = c.diskCache.Put(ctx, actionID, outputID, av.Size, putBody)
+	return outputID, diskPath, err
+}
+func (c *S3Cache) actionKey(actionID string) string {
+	return fmt.Sprintf("%s/actions/%s", c.prefix, actionID)
+}
+
+func (c *S3Cache) outputKey(outputID string) string {
+	return fmt.Sprintf("%s/output/%s", c.prefix, outputID)
+}
+
+func (c *S3Cache) Put(ctx context.Context, actionID, outputID string, size int64, body io.Reader) (diskPath string, _ error) {
+	// Write to disk locally as we write it remotely, as we need to guarantee
+	// it's on disk locally for the caller.
+	var readerForDisk io.Reader
+	var readerForS3 bytes.Buffer
+
+	if size == 0 {
+		// Special case the empty file so NewRequest sets "Content-Length: 0",
+		// as opposed to thinking we didn't set it and not being able to sniff its size
+		// from the type.
+		readerForDisk = bytes.NewReader(nil)
+	} else {
+		readerForDisk = io.TeeReader(body, &readerForS3)
+	}
+
+	diskPath, err := c.diskCache.Put(ctx, actionID, outputID, size, readerForDisk)
+	if err != nil {
+		return "", err
+	}
+
+	client, err := c.client(ctx)
+	if err != nil {
+		return "", err
+	}
+	av := ActionValue{
+		OutputID: outputID,
+		Size:     size,
+	}
+	avj, err := json.Marshal(av)
+	if err == nil {
+		actionKey := c.actionKey(actionID)
+		_, err = client.PutObject(ctx, &s3.PutObjectInput{
+			Bucket: &c.Bucket,
+			Key:    &actionKey,
+			Body:   bytes.NewReader(avj),
+		})
+	}
+	if size > 0 && err == nil {
+		outputKey := c.outputKey(outputID)
+		_, err = client.PutObject(ctx, &s3.PutObjectInput{
+			Bucket:        &c.Bucket,
+			Key:           &outputKey,
+			Body:          &readerForS3,
+			ContentLength: size,
+		})
+	}
+	return
+}

cmd/go-cacher/cacher.go

@@ -6,37 +6,97 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"log"
 	"os"
 	"path/filepath"
 
+	"github.com/aws/aws-sdk-go-v2/config"
+	"github.com/aws/aws-sdk-go-v2/credentials"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+
 	"github.com/bradfitz/go-tool-cache/cacheproc"
 	"github.com/bradfitz/go-tool-cache/cachers"
 )
 
+const defaultCacheKey = "v1"
+
 var (
-	dir        = flag.String("cache-dir", "", "cache directory; empty means automatic")
 	serverBase = flag.String("cache-server", "", "optional cache server HTTP prefix (scheme and authority only); should be low latency. empty means to not use one.")
 	verbose    = flag.Bool("verbose", false, "be verbose")
 )
 
+func getAwsConfigFromEnv() (*aws.Config, error) {
+	// read from env
+	awsRegion, awsRegionOk := os.LookupEnv("GOCACHE_AWS_REGION")
+	if !awsRegionOk {
+		return nil, nil
+	}
+	accessKey, accessKeyOk := os.LookupEnv("GOCACHE_AWS_ACCESS_KEY")
+	secretAccessKey, secretKeyOk := os.LookupEnv("GOCACHE_AWS_SECRET_ACCESS_KEY")
+	if accessKeyOk && secretKeyOk {
+		cfg, err := config.LoadDefaultConfig(context.TODO(),
+			config.WithRegion(awsRegion),
+			config.WithCredentialsProvider(credentials.StaticCredentialsProvider{
+				Value: aws.Credentials{
+					AccessKeyID:     accessKey,
+					SecretAccessKey: secretAccessKey,
+				},
+			}))
+		if err != nil {
+			return nil, err
+		}
+		return &cfg, nil
+	}
+	credsProfile, credsProfileOk := os.LookupEnv("GOCACHE_CREDS_PROFILE")
+	if credsProfileOk {
+		cfg, err := config.LoadDefaultConfig(context.TODO(), config.WithRegion(awsRegion), config.WithSharedConfigProfile(credsProfile))
+		if err != nil {
+			return nil, err
+		}
+		return &cfg, nil
+	}
+	return nil, nil
+}
+
+func maybeS3Cache(dc *cachers.DiskCache) (*cachers.S3Cache, error) {
+	awsConfig, err := getAwsConfigFromEnv()
+	if err != nil {
+		return nil, err
+	}
+	bucket, ok := os.LookupEnv("GOCACHE_S3_BUCKET")
+	if !ok || awsConfig == nil {
+		// We need at least name of bucket and valid aws config
+		return nil, nil
+	}
+	cacheKey := os.Getenv("GOCACHE_CACHE_KEY")
+	if cacheKey == "" {
+		cacheKey = defaultCacheKey
+	}
+
+	s3Cache := cachers.NewS3Cache(bucket, awsConfig, cacheKey, dc, *verbose)
+	return s3Cache, nil
+}
+
 func main() {
 	flag.Parse()
-	if *dir == "" {
+	dir := os.Getenv("GOCACHE_DISK_DIR")
+	if dir == "" {
 		d, err := os.UserCacheDir()
 		if err != nil {
 			log.Fatal(err)
 		}
 		d = filepath.Join(d, "go-cacher")
-		log.Printf("Defaulting to cache dir %v ...", d)
-		*dir = d
+		dir = d
 	}
-	if err := os.MkdirAll(*dir, 0755); err != nil {
+	log.Printf("cache dir %v ...", dir)
+	if err := os.MkdirAll(dir, 0755); err != nil {
 		log.Fatal(err)
 	}
 
-	dc := &cachers.DiskCache{Dir: *dir}
+	dc := &cachers.DiskCache{Dir: dir}
 
 	var p *cacheproc.Process
 	p = &cacheproc.Process{
@@ -61,6 +121,15 @@ func main() {
 		p.Put = hc.Put
 	}
 
+	s3Cache, err := maybeS3Cache(dc)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if s3Cache != nil {
+		p.Get = s3Cache.Get
+		p.Put = s3Cache.Put
+	}
+
 	if err := p.Run(); err != nil {
 		log.Fatal(err)
 	}

go.mod

@@ -1,3 +1,27 @@
 module github.com/bradfitz/go-tool-cache
 
-go 1.20
+go 1.21
+
+require (
+	github.com/aws/aws-sdk-go-v2 v1.22.2
+	github.com/aws/aws-sdk-go-v2/config v1.23.0
+	github.com/aws/aws-sdk-go-v2/credentials v1.15.2
+	github.com/aws/aws-sdk-go-v2/service/s3 v1.42.1
+)
+
+require (
+	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.5.0 // indirect
+	github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.14.3 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/configsources v1.2.2 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.5.2 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/ini v1.6.0 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/v4a v1.2.2 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.10.0 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/checksum v1.2.2 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.10.2 // indirect
+	github.com/aws/aws-sdk-go-v2/service/internal/s3shared v1.16.2 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sso v1.17.1 // indirect
+	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.19.1 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sts v1.25.1 // indirect
+	github.com/aws/smithy-go v1.16.0 // indirect
+)

go.sum

@@ -0,0 +1,39 @@
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+github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.5.0 h1:hHgLiIrTRtddC0AKcJr5s7i/hLgcpTt+q/FKxf1Zayk=
+github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.5.0/go.mod h1:w4I/v3NOWgD+qvs1NPEwhd++1h3XPHFaVxasfY6HlYQ=
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