Support for GCS source using Blob sync.

Signed-off-by: Alan Kutniewski <kutniewski@google.com>

core/go.mod

@@ -41,6 +41,10 @@ require (
 )
 
 require (
+	cloud.google.com/go v0.112.1 // indirect
+	cloud.google.com/go/compute/metadata v0.3.0 // indirect
+	cloud.google.com/go/iam v1.1.6 // indirect
+	cloud.google.com/go/storage v1.39.1 // indirect
 	github.com/Masterminds/goutils v1.1.1 // indirect
 	github.com/Masterminds/semver v1.5.0 // indirect
 	github.com/barkimedes/go-deepcopy v0.0.0-20220514131651-17c30cfc62df // indirect
@@ -63,7 +67,9 @@ require (
 	github.com/google/gnostic-models v0.6.8 // indirect
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
+	github.com/google/s2a-go v0.1.7 // indirect
 	github.com/google/uuid v1.6.0 // indirect
+	github.com/googleapis/enterprise-certificate-proxy v0.3.2 // indirect
 	github.com/googleapis/gax-go/v2 v2.12.2 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.20.0 // indirect
 	github.com/huandu/xstrings v1.4.0 // indirect
@@ -96,6 +102,7 @@ require (
 	golang.org/x/xerrors v0.0.0-20231012003039-104605ab7028 // indirect
 	gomodules.xyz/jsonpatch/v2 v2.4.0 // indirect
 	google.golang.org/api v0.169.0 // indirect
+	google.golang.org/genproto v0.0.0-20240311173647-c811ad7063a7 // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20240701130421-f6361c86f094 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240701130421-f6361c86f094 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect

core/go.sum

@@ -55,9 +55,11 @@ cloud.google.com/go v0.110.2/go.mod h1:k04UEeEtb6ZBRTv3dZz4CeJC3jKGxyhl0sAiVVqux
 cloud.google.com/go v0.110.4/go.mod h1:+EYjdK8e5RME/VY/qLCAtuyALQ9q67dvuum8i+H5xsI=
 cloud.google.com/go v0.110.6/go.mod h1:+EYjdK8e5RME/VY/qLCAtuyALQ9q67dvuum8i+H5xsI=
 cloud.google.com/go v0.110.7/go.mod h1:+EYjdK8e5RME/VY/qLCAtuyALQ9q67dvuum8i+H5xsI=
+cloud.google.com/go v0.110.8 h1:tyNdfIxjzaWctIiLYOTalaLKZ17SI44SKFW26QbOhME=
 cloud.google.com/go v0.110.8/go.mod h1:Iz8AkXJf1qmxC3Oxoep8R1T36w8B92yU29PcBhHO5fk=
 cloud.google.com/go v0.110.9/go.mod h1:rpxevX/0Lqvlbc88b7Sc1SPNdyK1riNBTUU6JXhYNpM=
 cloud.google.com/go v0.110.10/go.mod h1:v1OoFqYxiBkUrruItNM3eT4lLByNjxmJSV/xDKJNnic=
+cloud.google.com/go v0.112.1/go.mod h1:+Vbu+Y1UU+I1rjmzeMOb/8RfkKJK2Gyxi1X6jJCZLo4=
 cloud.google.com/go/accessapproval v1.4.0/go.mod h1:zybIuC3KpDOvotz59lFe5qxRZx6C75OtwbisN56xYB4=
 cloud.google.com/go/accessapproval v1.5.0/go.mod h1:HFy3tuiGvMdcd/u+Cu5b9NkO1pEICJ46IR82PoUdplw=
 cloud.google.com/go/accessapproval v1.6.0/go.mod h1:R0EiYnwV5fsRFiKZkPHr6mwyk2wxUJ30nL4j2pcFY2E=
@@ -314,13 +316,17 @@ cloud.google.com/go/compute v1.19.3/go.mod h1:qxvISKp/gYnXkSAD1ppcSOveRAmzxicEv/
 cloud.google.com/go/compute v1.20.1/go.mod h1:4tCnrn48xsqlwSAiLf1HXMQk8CONslYbdiEZc9FEIbM=
 cloud.google.com/go/compute v1.21.0/go.mod h1:4tCnrn48xsqlwSAiLf1HXMQk8CONslYbdiEZc9FEIbM=
 cloud.google.com/go/compute v1.23.0/go.mod h1:4tCnrn48xsqlwSAiLf1HXMQk8CONslYbdiEZc9FEIbM=
+cloud.google.com/go/compute v1.23.1 h1:V97tBoDaZHb6leicZ1G6DLK2BAaZLJ/7+9BB/En3hR0=
 cloud.google.com/go/compute v1.23.1/go.mod h1:CqB3xpmPKKt3OJpW2ndFIXnA9A4xAy/F3Xp1ixncW78=
 cloud.google.com/go/compute v1.23.2/go.mod h1:JJ0atRC0J/oWYiiVBmsSsrRnh92DhZPG4hFDcR04Rns=
 cloud.google.com/go/compute v1.23.3/go.mod h1:VCgBUoMnIVIR0CscqQiPJLAG25E3ZRZMzcFZeQ+h8CI=
+cloud.google.com/go/compute v1.25.0 h1:H1/4SqSUhjPFE7L5ddzHOfY2bCAvjwNRZPNl6Ni5oYU=
 cloud.google.com/go/compute/metadata v0.1.0/go.mod h1:Z1VN+bulIf6bt4P/C37K4DyZYZEXYonfTBHHFPO/4UU=
 cloud.google.com/go/compute/metadata v0.2.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
 cloud.google.com/go/compute/metadata v0.2.1/go.mod h1:jgHgmJd2RKBGzXqF5LR2EZMGxBkeanZ9wwa75XHJgOM=
 cloud.google.com/go/compute/metadata v0.2.3/go.mod h1:VAV5nSsACxMJvgaAuX6Pk2AawlZn8kiOGuCv6gTkwuA=
+cloud.google.com/go/compute/metadata v0.3.0 h1:Tz+eQXMEqDIKRsmY3cHTL6FVaynIjX2QxYC4trgAKZc=
+cloud.google.com/go/compute/metadata v0.3.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
 cloud.google.com/go/contactcenterinsights v1.3.0/go.mod h1:Eu2oemoePuEFc/xKFPjbTuPSj0fYJcPls9TFlPNnHHY=
 cloud.google.com/go/contactcenterinsights v1.4.0/go.mod h1:L2YzkGbPsv+vMQMCADxJoT9YiTTnSEd6fEvCeHTYVck=
 cloud.google.com/go/contactcenterinsights v1.6.0/go.mod h1:IIDlT6CLcDoyv79kDv8iWxMSTZhLxSCofVV5W6YFM/w=
@@ -600,9 +606,11 @@ cloud.google.com/go/iam v1.0.1/go.mod h1:yR3tmSL8BcZB4bxByRv2jkSIahVmCtfKZwLYGBa
 cloud.google.com/go/iam v1.1.0/go.mod h1:nxdHjaKfCr7fNYx/HJMM8LgiMugmveWlkatear5gVyk=
 cloud.google.com/go/iam v1.1.1/go.mod h1:A5avdyVL2tCppe4unb0951eI9jreack+RJ0/d+KUZOU=
 cloud.google.com/go/iam v1.1.2/go.mod h1:A5avdyVL2tCppe4unb0951eI9jreack+RJ0/d+KUZOU=
+cloud.google.com/go/iam v1.1.3 h1:18tKG7DzydKWUnLjonWcJO6wjSCAtzh4GcRKlH/Hrzc=
 cloud.google.com/go/iam v1.1.3/go.mod h1:3khUlaBXfPKKe7huYgEpDn6FtgRyMEqbkvBxrQyY5SE=
 cloud.google.com/go/iam v1.1.4/go.mod h1:l/rg8l1AaA+VFMho/HYx2Vv6xinPSLMF8qfhRPIZ0L8=
 cloud.google.com/go/iam v1.1.5/go.mod h1:rB6P/Ic3mykPbFio+vo7403drjlgvoWfYpJhMXEbzv8=
+cloud.google.com/go/iam v1.1.6/go.mod h1:O0zxdPeGBoFdWW3HWmBxJsk0pfvNM/p/qa82rWOGTwI=
 cloud.google.com/go/iap v1.4.0/go.mod h1:RGFwRJdihTINIe4wZ2iCP0zF/qu18ZwyKxrhMhygBEc=
 cloud.google.com/go/iap v1.5.0/go.mod h1:UH/CGgKd4KyohZL5Pt0jSKE4m3FR51qg6FKQ/z/Ix9A=
 cloud.google.com/go/iap v1.6.0/go.mod h1:NSuvI9C/j7UdjGjIde7t7HBz+QTwBcapPE07+sSRcLk=
@@ -1016,6 +1024,10 @@ cloud.google.com/go/storage v1.27.0/go.mod h1:x9DOL8TK/ygDUMieqwfhdpQryTeEkhGKMi
 cloud.google.com/go/storage v1.28.1/go.mod h1:Qnisd4CqDdo6BGs2AD5LLnEsmSQ80wQ5ogcBBKhU86Y=
 cloud.google.com/go/storage v1.29.0/go.mod h1:4puEjyTKnku6gfKoTfNOU/W+a9JyuVNxjpS5GBrB8h4=
 cloud.google.com/go/storage v1.30.1/go.mod h1:NfxhC0UJE1aXSx7CIIbCf7y9HKT7BiccwkR7+P7gN8E=
+cloud.google.com/go/storage v1.35.1 h1:B59ahL//eDfx2IIKFBeT5Atm9wnNmj3+8xG/W4WB//w=
+cloud.google.com/go/storage v1.35.1/go.mod h1:M6M/3V/D3KpzMTJyPOR/HU6n2Si5QdaXYEsng2xgOs8=
+cloud.google.com/go/storage v1.39.1 h1:MvraqHKhogCOTXTlct/9C3K3+Uy2jBmFYb3/Sp6dVtY=
+cloud.google.com/go/storage v1.39.1/go.mod h1:xK6xZmxZmo+fyP7+DEF6FhNc24/JAe95OLyOHCXFH1o=
 cloud.google.com/go/storagetransfer v1.5.0/go.mod h1:dxNzUopWy7RQevYFHewchb29POFv3/AaBgnhqzqiK0w=
 cloud.google.com/go/storagetransfer v1.6.0/go.mod h1:y77xm4CQV/ZhFZH75PLEXY0ROiS7Gh6pSKrM8dJyg6I=
 cloud.google.com/go/storagetransfer v1.7.0/go.mod h1:8Giuj1QNb1kfLAiWM1bN6dHzfdlDAVC9rv9abHot2W4=
@@ -1374,6 +1386,7 @@ github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm4
 github.com/google/s2a-go v0.1.0/go.mod h1:OJpEgntRZo8ugHpF9hkoLJbS5dSI20XZeXJ9JVywLlM=
 github.com/google/s2a-go v0.1.3/go.mod h1:Ej+mSEMGRnqRzjc7VtF+jdBwYG5fuJfiZ8ELkjEwM0A=
 github.com/google/s2a-go v0.1.4/go.mod h1:Ej+mSEMGRnqRzjc7VtF+jdBwYG5fuJfiZ8ELkjEwM0A=
+github.com/google/s2a-go v0.1.7 h1:60BLSyTrOV4/haCDW4zb1guZItoSq8foHCXrAnjBo/o=
 github.com/google/s2a-go v0.1.7/go.mod h1:50CgR4k1jNlWBu4UfS4AcfhVe1r6pdZPygJ3R8F0Qdw=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
@@ -1388,6 +1401,7 @@ github.com/googleapis/enterprise-certificate-proxy v0.2.1/go.mod h1:AwSRAtLfXpU5
 github.com/googleapis/enterprise-certificate-proxy v0.2.3/go.mod h1:AwSRAtLfXpU5Nm3pW+v7rGDHp09LsPtGY9MduiEsR9k=
 github.com/googleapis/enterprise-certificate-proxy v0.2.4/go.mod h1:AwSRAtLfXpU5Nm3pW+v7rGDHp09LsPtGY9MduiEsR9k=
 github.com/googleapis/enterprise-certificate-proxy v0.2.5/go.mod h1:RxW0N9901Cko1VOCW3SXCpWP+mlIEkk2tP7jnHy9a3w=
+github.com/googleapis/enterprise-certificate-proxy v0.3.2 h1:Vie5ybvEvT75RniqhfFxPRy3Bf7vr3h0cechB90XaQs=
 github.com/googleapis/enterprise-certificate-proxy v0.3.2/go.mod h1:VLSiSSBs/ksPL8kq3OBOQ6WRI2QnaFynd1DCjZ62+V0=
 github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+vpHVxEJEs9eg=
 github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5mhpdKc/us6bOk=
@@ -1403,6 +1417,7 @@ github.com/googleapis/gax-go/v2 v2.7.1/go.mod h1:4orTrqY6hXxxaUL4LHIPl6lGo8vAE38
 github.com/googleapis/gax-go/v2 v2.8.0/go.mod h1:4orTrqY6hXxxaUL4LHIPl6lGo8vAE38/qKbhSAKP6QI=
 github.com/googleapis/gax-go/v2 v2.10.0/go.mod h1:4UOEnMCrxsSqQ940WnTiD6qJ63le2ev3xfyagutxiPw=
 github.com/googleapis/gax-go/v2 v2.11.0/go.mod h1:DxmR61SGKkGLa2xigwuZIQpkCI2S5iydzRfb3peWZJI=
+github.com/googleapis/gax-go/v2 v2.12.0 h1:A+gCJKdRfqXkr+BIRGtZLibNXf0m1f9E4HG56etFpas=
 github.com/googleapis/gax-go/v2 v2.12.0/go.mod h1:y+aIqrI5eb1YGMVJfuV3185Ts/D7qKpsEkdD5+I6QGU=
 github.com/googleapis/gax-go/v2 v2.12.2 h1:mhN09QQW1jEWeMF74zGR81R30z4VJzjZsfkUhuHF+DA=
 github.com/googleapis/gax-go/v2 v2.12.2/go.mod h1:61M8vcyyXR2kqKFxKrfA22jaA8JGF7Dc8App1U3H6jc=
@@ -2090,6 +2105,7 @@ golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8T
 golang.org/x/xerrors v0.0.0-20220411194840-2f41105eb62f/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20220517211312-f3a8303e98df/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
 golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
+golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 h1:H2TDz8ibqkAF6YGhCdN3jS9O0/s90v0rJh3X/OLHEUk=
 golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2/go.mod h1:K8+ghG5WaK9qNqU5K3HdILfMLy1f3aNYFI/wnl100a8=
 golang.org/x/xerrors v0.0.0-20231012003039-104605ab7028 h1:+cNy6SZtPcJQH3LJVLOSmiC7MMxXNOb3PU/VUEz+EhU=
 golang.org/x/xerrors v0.0.0-20231012003039-104605ab7028/go.mod h1:NDW/Ps6MPRej6fsCIbMTohpP40sJ/P/vI1MoTEGwX90=
@@ -2168,6 +2184,8 @@ google.golang.org/api v0.126.0/go.mod h1:mBwVAtz+87bEN6CbA1GtZPDOqY2R5ONPqJeIlvy
 google.golang.org/api v0.128.0/go.mod h1:Y611qgqaE92On/7g65MQgxYul3c0rEB894kniWLY750=
 google.golang.org/api v0.139.0/go.mod h1:CVagp6Eekz9CjGZ718Z+sloknzkDJE7Vc1Ckj9+viBk=
 google.golang.org/api v0.149.0/go.mod h1:Mwn1B7JTXrzXtnvmzQE2BD6bYZQ8DShKZDZbeN9I7qI=
+google.golang.org/api v0.150.0 h1:Z9k22qD289SZ8gCJrk4DrWXkNjtfvKAUo/l1ma8eBYE=
+google.golang.org/api v0.150.0/go.mod h1:ccy+MJ6nrYFgE3WgRx/AMXOxOmU8Q4hSa+jjibzhxcg=
 google.golang.org/api v0.169.0 h1:QwWPy71FgMWqJN/l6jVlFHUa29a7dcUy02I8o799nPY=
 google.golang.org/api v0.169.0/go.mod h1:gpNOiMA2tZ4mf5R9Iwf4rK/Dcz0fbdIgWYWVoxmsyLg=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
@@ -2326,9 +2344,12 @@ google.golang.org/genproto v0.0.0-20230913181813-007df8e322eb/go.mod h1:yZTlhN0t
 google.golang.org/genproto v0.0.0-20230920204549-e6e6cdab5c13/go.mod h1:CCviP9RmpZ1mxVr8MUjCnSiY09IbAXZxhLE6EhHIdPU=
 google.golang.org/genproto v0.0.0-20231002182017-d307bd883b97/go.mod h1:t1VqOqqvce95G3hIDCT5FeO3YUc6Q4Oe24L/+rNMxRk=
 google.golang.org/genproto v0.0.0-20231012201019-e917dd12ba7a/go.mod h1:EMfReVxb80Dq1hhioy0sOsY9jCE46YDgHlJ7fWVUWRE=
+google.golang.org/genproto v0.0.0-20231016165738-49dd2c1f3d0b h1:+YaDE2r2OG8t/z5qmsh7Y+XXwCbvadxxZ0YY6mTdrVA=
 google.golang.org/genproto v0.0.0-20231016165738-49dd2c1f3d0b/go.mod h1:CgAqfJo+Xmu0GwA0411Ht3OU3OntXwsGmrmjI8ioGXI=
 google.golang.org/genproto v0.0.0-20231030173426-d783a09b4405/go.mod h1:3WDQMjmJk36UQhjQ89emUzb1mdaHcPeeAh4SCBKznB4=
 google.golang.org/genproto v0.0.0-20231106174013-bbf56f31fb17/go.mod h1:J7XzRzVy1+IPwWHZUzoD0IccYZIrXILAQpc+Qy9CMhY=
+google.golang.org/genproto v0.0.0-20240311173647-c811ad7063a7 h1:ImUcDPHjTrAqNhlOkSocDLfG9rrNHH7w7uoKWPaWZ8s=
+google.golang.org/genproto v0.0.0-20240311173647-c811ad7063a7/go.mod h1:/3XmxOjePkvmKrHuBy4zNFw7IzxJXtAgdpXi8Ll990U=
 google.golang.org/genproto/googleapis/api v0.0.0-20230525234020-1aefcd67740a/go.mod h1:ts19tUU+Z0ZShN1y3aPyq2+O3d5FUNNgT6FtOzmrNn8=
 google.golang.org/genproto/googleapis/api v0.0.0-20230525234035-dd9d682886f9/go.mod h1:vHYtlOoi6TsQ3Uk2yxR7NI5z8uoV+3pZtR4jmHIkRig=
 google.golang.org/genproto/googleapis/api v0.0.0-20230526203410-71b5a4ffd15e/go.mod h1:vHYtlOoi6TsQ3Uk2yxR7NI5z8uoV+3pZtR4jmHIkRig=

core/pkg/sync/blob/blob_sync.go

@@ -11,6 +11,7 @@ import (
 	"github.com/open-feature/flagd/core/pkg/logger"
 	"github.com/open-feature/flagd/core/pkg/sync"
 	"gocloud.dev/blob"
+	_ "gocloud.dev/blob/gcsblob" // needed to initialize GCS driver
 	//nolint:gosec
 )
 

core/pkg/sync/builder/syncbuilder.go

@@ -10,13 +10,15 @@ import (
 
 	"github.com/open-feature/flagd/core/pkg/logger"
 	"github.com/open-feature/flagd/core/pkg/sync"
+	blobSync "github.com/open-feature/flagd/core/pkg/sync/blob"
 	"github.com/open-feature/flagd/core/pkg/sync/file"
 	"github.com/open-feature/flagd/core/pkg/sync/grpc"
 	"github.com/open-feature/flagd/core/pkg/sync/grpc/credentials"
 	httpSync "github.com/open-feature/flagd/core/pkg/sync/http"
 	"github.com/open-feature/flagd/core/pkg/sync/kubernetes"
 	"github.com/robfig/cron"
 	"go.uber.org/zap"
+	"gocloud.dev/blob"
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
@@ -27,6 +29,7 @@ const (
 	syncProviderGrpc       = "grpc"
 	syncProviderKubernetes = "kubernetes"
 	syncProviderHTTP       = "http"
+	syncProviderGcs        = "gcs"
 )
 
 var (
@@ -35,6 +38,7 @@ var (
 	regGRPC       *regexp.Regexp
 	regGRPCSecure *regexp.Regexp
 	regFile       *regexp.Regexp
+	regGcs        *regexp.Regexp
 )
 
 func init() {
@@ -43,6 +47,7 @@ func init() {
 	regGRPC = regexp.MustCompile("^" + grpc.Prefix)
 	regGRPCSecure = regexp.MustCompile("^" + grpc.PrefixSecure)
 	regFile = regexp.MustCompile("^file:")
+	regGcs = regexp.MustCompile("^gs://.+?/")
 }
 
 type ISyncBuilder interface {
@@ -97,6 +102,9 @@ func (sb *SyncBuilder) syncFromConfig(sourceConfig sync.SourceConfig, logger *lo
 	case syncProviderGrpc:
 		logger.Debug(fmt.Sprintf("using grpc sync-provider for: %s", sourceConfig.URI))
 		return sb.newGRPC(sourceConfig, logger), nil
+	case syncProviderGcs:
+		logger.Debug(fmt.Sprintf("using blob sync-provider with gcs driver for: %s", sourceConfig.URI))
+		return sb.newGcs(sourceConfig, logger), nil
 
 	default:
 		return nil, fmt.Errorf("invalid sync provider: %s, must be one of with '%s', '%s', '%s' or '%s'",
@@ -170,6 +178,34 @@ func (sb *SyncBuilder) newGRPC(config sync.SourceConfig, logger *logger.Logger)
 	}
 }
 
+func (sb *SyncBuilder) newGcs(config sync.SourceConfig, logger *logger.Logger) *blobSync.Sync {
+	// Extract bucket uri and object name from the full URI:
+	// gs://bucket/path/to/object results in gs://bucket/ as bucketUri and
+	// path/to/object as an object name.
+	bucketUri := regGcs.FindString(config.URI)
+	objectName := regGcs.ReplaceAllString(config.URI, "")
+
+	// Defaults to 5 seconds if interval is not set.
+	var interval uint32 = 5
+	if config.Interval != 0 {
+		interval = config.Interval
+	}
+
+	return &blobSync.Sync{
+		Bucket: bucketUri,
+		Object: objectName,
+
+		BlobURLMux: blob.DefaultURLMux(),
+
+		Logger: logger.WithFields(
+			zap.String("component", "sync"),
+			zap.String("sync", "gcs"),
+		),
+		Interval: interval,
+		Cron:     cron.New(),
+	}
+}
+
 type IK8sClientBuilder interface {
 	GetK8sClient() (dynamic.Interface, error)
 }

core/pkg/sync/builder/syncbuilder_test.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/open-feature/flagd/core/pkg/logger"
 	"github.com/open-feature/flagd/core/pkg/sync"
+	"github.com/open-feature/flagd/core/pkg/sync/blob"
 	buildermock "github.com/open-feature/flagd/core/pkg/sync/builder/mock"
 	"github.com/open-feature/flagd/core/pkg/sync/file"
 	"github.com/open-feature/flagd/core/pkg/sync/grpc"
@@ -231,6 +232,10 @@ func Test_SyncsFromFromConfig(t *testing.T) {
 						URI:      "my-namespace/my-flags",
 						Provider: syncProviderKubernetes,
 					},
+					{
+						URI:      "gs://bucket/path/to/file",
+						Provider: syncProviderGcs,
+					},
 				},
 			},
 			wantSyncs: []sync.ISync{
@@ -239,6 +244,7 @@ func Test_SyncsFromFromConfig(t *testing.T) {
 				&http.Sync{},
 				&file.Sync{},
 				&kubernetes.Sync{},
+				&blob.Sync{},
 			},
 			wantErr: false,
 		},
@@ -264,3 +270,57 @@ func Test_SyncsFromFromConfig(t *testing.T) {
 		})
 	}
 }
+
+func Test_GcsConfig(t *testing.T) {
+	lg := logger.NewLogger(nil, false)
+	defaultInterval := uint32(5)
+	tests := []struct {
+		name             string
+		uri              string
+		interval         uint32
+		expectedBucket   string
+		expectedObject   string
+		expectedInterval uint32
+	}{
+		{
+			name:             "simple path",
+			uri:              "gs://bucket/path/to/object",
+			interval:         10,
+			expectedBucket:   "gs://bucket/",
+			expectedObject:   "path/to/object",
+			expectedInterval: 10,
+		},
+		{
+			name:             "default interval",
+			uri:              "gs://bucket/path/to/object",
+			expectedBucket:   "gs://bucket/",
+			expectedObject:   "path/to/object",
+			expectedInterval: defaultInterval,
+		},
+		{
+			name:             "no object set", // Blob syncer will return error when fetching
+			uri:              "gs://bucket/",
+			expectedBucket:   "gs://bucket/",
+			expectedObject:   "",
+			expectedInterval: defaultInterval,
+		},
+		{
+			name:             "malformed uri", // Blob syncer will return error when opening bucket
+			uri:              "malformed",
+			expectedBucket:   "",
+			expectedObject:   "malformed",
+			expectedInterval: defaultInterval,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gcsSync := NewSyncBuilder().newGcs(sync.SourceConfig{
+				URI:      tt.uri,
+				Interval: tt.interval,
+			}, lg)
+			require.Equal(t, tt.expectedBucket, gcsSync.Bucket)
+			require.Equal(t, tt.expectedObject, gcsSync.Object)
+			require.Equal(t, int(tt.expectedInterval), int(gcsSync.Interval))
+		})
+	}
+}

core/pkg/sync/builder/utils.go

@@ -64,9 +64,14 @@ func ParseSyncProviderURIs(uris []string) ([]sync.SourceConfig, error) {
 				Provider: syncProviderGrpc,
 				TLS:      true,
 			})
+		case regGcs.Match(uriB):
+			syncProvidersParsed = append(syncProvidersParsed, sync.SourceConfig{
+				URI:      uri,
+				Provider: syncProviderGcs,
+			})
 		default:
 			return syncProvidersParsed, fmt.Errorf("invalid sync uri argument: %s, must start with 'file:', "+
-				"'http(s)://', 'grpc(s)://', or 'core.openfeature.dev'", uri)
+				"'http(s)://', 'grpc(s)://', 'gs://' or 'core.openfeature.dev'", uri)
 		}
 	}
 	return syncProvidersParsed, nil

core/pkg/sync/builder/utils_test.go

@@ -28,7 +28,8 @@ func TestParseSource(t *testing.T) {
 					{"uri":"config/samples/example_flags.json","provider":"file"},
 					{"uri":"http://test.com","provider":"http","bearerToken":":)"},
 					{"uri":"host:port","provider":"grpc"},
-					{"uri":"default/my-crd","provider":"kubernetes"}
+					{"uri":"default/my-crd","provider":"kubernetes"},
+					{"uri":"gs://bucket-name/path/to/file","provider":"gcs"}
 				]`,
 			expectErr: false,
 			out: []sync.SourceConfig{
@@ -49,6 +50,10 @@ func TestParseSource(t *testing.T) {
 					URI:      "default/my-crd",
 					Provider: syncProviderKubernetes,
 				},
+				{
+					URI:      "gs://bucket-name/path/to/file",
+					Provider: syncProviderGcs,
+				},
 			},
 		},
 		"multiple-syncs-with-options": {
@@ -182,6 +187,7 @@ func TestParseSyncProviderURIs(t *testing.T) {
 				"grpc://host:port",
 				"grpcs://secure-grpc",
 				"core.openfeature.dev/default/my-crd",
+				"gs://bucket-name/path/to/file",
 			},
 			expectErr: false,
 			out: []sync.SourceConfig{
@@ -207,6 +213,10 @@ func TestParseSyncProviderURIs(t *testing.T) {
 					URI:      "default/my-crd",
 					Provider: "kubernetes",
 				},
+				{
+					URI:      "gs://bucket-name/path/to/file",
+					Provider: syncProviderGcs,
+				},
 			},
 		},
 		"empty": {