Add Azure Blob storage backend

README.md

@@ -25,6 +25,7 @@ A Terraform / OpenTofu state migration tool for GitOps.
          * [storage block (local)](#storage-block-local)
          * [storage block (s3)](#storage-block-s3)
          * [storage block (gcs)](#storage-block-gcs)
+         * [storage block (azurerm)](#storage-block-azurerm)
    * [Migration file](#migration-file)
       * [Environment Variables](#environment-variables-1)
       * [migration block](#migration-block)
@@ -429,6 +430,7 @@ The storage block has one label, which is a type of storage. Valid types are as
 - `local`: Save a history file to local filesystem.
 - `s3`: Save a history file to AWS S3.
 - `gcs`: Save a history file to GCS (Google Cloud Storage).
+- `azurerm`: Save a history file to Azure Blob storage.
 
 If your cloud provider has not been supported yet, as a workaround, you can use `local` storage and synchronize a history file to your cloud storage with a wrapper script.
 
@@ -512,6 +514,33 @@ tfmigrate {
 
 If you want to connect to an emulator instead of GCS, set the `STORAGE_EMULATOR_HOST` environment variable as required by the [Go library for GCS](https://pkg.go.dev/cloud.google.com/go/storage).
 
+#### storage block (azurerm)
+
+The `azurerm` storage has the following attributes:
+
+- `access_key` (optional): Access key for the blob storage container. If omitted, this value is read from the `TFMIGRATE_AZURERM_STORAGE_ACCESS_KEY` environment variable.
+- `storage_account_name` (required): Name of the storage account.
+- `container_name` (required): Name of the storage container.
+- `blob_name` (optional): Name of the migration history file. Defaults to `history.json` if omitted.
+
+Note that the `azurerm` backend expects that the storage account, container and blob already exist.
+
+An example of configuration file is as follows.
+
+```hcl
+tfmigrate {
+  migration_dir = "./tfmigrate"
+  history {
+    storage "azurerm" {
+      access_key = "<storage access key>"
+      storage_account_name = "storage"
+      container_name = "tfmigrate-test"
+      blob_name = "tfmigrate-history.json"
+    }
+  }
+}
+```
+
 ## Migration file
 
 You can write terraform state operations in HCL. The syntax of migration file is as follows:

config/storage.go

@@ -6,6 +6,7 @@ import (
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/gohcl"
 	"github.com/minamijoyo/tfmigrate/storage"
+	"github.com/minamijoyo/tfmigrate/storage/azure"
 	"github.com/minamijoyo/tfmigrate/storage/gcs"
 	"github.com/minamijoyo/tfmigrate/storage/local"
 	"github.com/minamijoyo/tfmigrate/storage/mock"
@@ -35,6 +36,9 @@ func parseStorageBlock(b StorageBlock) (storage.Config, error) {
 	case "local":
 		return parseLocalStorageBlock(b)
 
+	case "azurerm":
+		return parseAzureStorageBlock(b)
+
 	case "s3":
 		return parseS3StorageBlock(b)
 
@@ -68,6 +72,17 @@ func parseLocalStorageBlock(b StorageBlock) (storage.Config, error) {
 	return &config, nil
 }
 
+// parseAzureStorageBlock parses a storage block for azure and returns a storage.Config.
+func parseAzureStorageBlock(b StorageBlock) (storage.Config, error) {
+	var config azure.Config
+	diags := gohcl.DecodeBody(b.Remain, nil, &config)
+	if diags.HasErrors() {
+		return nil, diags
+	}
+
+	return &config, nil
+}
+
 // parseS3StorageBlock parses a storage block for s3 and returns a storage.Config.
 func parseS3StorageBlock(b StorageBlock) (storage.Config, error) {
 	var config s3.Config

go.mod

@@ -4,6 +4,8 @@ go 1.22
 
 require (
 	cloud.google.com/go/storage v1.25.0
+	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.5.1
+	github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v1.3.1
 	github.com/aws/aws-sdk-go v1.43.22
 	github.com/davecgh/go-spew v1.1.1
 	github.com/google/go-cmp v0.5.8
@@ -20,32 +22,39 @@ require (
 	cloud.google.com/go v0.102.1 // indirect
 	cloud.google.com/go/compute v1.7.0 // indirect
 	cloud.google.com/go/iam v0.3.0 // indirect
+	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.9.2 // indirect
+	github.com/Azure/azure-sdk-for-go/sdk/internal v1.5.2 // indirect
+	github.com/AzureAD/microsoft-authentication-library-for-go v1.2.1 // indirect
 	github.com/agext/levenshtein v1.2.1 // indirect
 	github.com/apparentlymart/go-textseg v1.0.0 // indirect
 	github.com/apparentlymart/go-textseg/v12 v12.0.0 // indirect
 	github.com/armon/go-radix v0.0.0-20180808171621-7fddfc383310 // indirect
 	github.com/bgentry/speakeasy v0.1.0 // indirect
 	github.com/fatih/color v1.7.0 // indirect
+	github.com/golang-jwt/jwt/v5 v5.2.0 // indirect
 	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
 	github.com/golang/protobuf v1.5.2 // indirect
-	github.com/google/uuid v1.3.0 // indirect
+	github.com/google/uuid v1.6.0 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.1.0 // indirect
 	github.com/googleapis/gax-go/v2 v2.4.0 // indirect
 	github.com/hashicorp/errwrap v1.0.0 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.0 // indirect
 	github.com/hashicorp/go-multierror v1.0.0 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
+	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/mattn/go-colorable v0.0.9 // indirect
 	github.com/mattn/go-isatty v0.0.3 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7 // indirect
+	github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c // indirect
 	github.com/posener/complete v1.1.1 // indirect
 	github.com/zclconf/go-cty v1.2.0 // indirect
 	go.opencensus.io v0.23.0 // indirect
-	golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e // indirect
+	golang.org/x/crypto v0.18.0 // indirect
+	golang.org/x/net v0.20.0 // indirect
 	golang.org/x/oauth2 v0.0.0-20220622183110-fd043fe589d2 // indirect
-	golang.org/x/sys v0.0.0-20220624220833-87e55d714810 // indirect
-	golang.org/x/text v0.3.7 // indirect
+	golang.org/x/sys v0.16.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
 	golang.org/x/xerrors v0.0.0-20220609144429-65e65417b02f // indirect
 	google.golang.org/api v0.88.0 // indirect
 	google.golang.org/appengine v1.6.7 // indirect

go.sum

@@ -60,6 +60,20 @@ cloud.google.com/go/storage v1.22.1/go.mod h1:S8N1cAStu7BOeFfE8KAQzmyyLkK8p/vmRq
 cloud.google.com/go/storage v1.25.0 h1:D2Dn0PslpK7Z3B2AvuUHyIC762bDbGJdlmQlCBR71os=
 cloud.google.com/go/storage v1.25.0/go.mod h1:Qys4JU+jeup3QnuKKAosWuxrD95C4MSqxfVDnSirDsI=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
+github.com/Azure/azure-sdk-for-go/sdk/azcore v1.9.1 h1:lGlwhPtrX6EVml1hO0ivjkUxsSyl4dsiw9qcA1k/3IQ=
+github.com/Azure/azure-sdk-for-go/sdk/azcore v1.9.1/go.mod h1:RKUqNu35KJYcVG/fqTRqmuXJZYNhYkBrnC/hX7yGbTA=
+github.com/Azure/azure-sdk-for-go/sdk/azcore v1.9.2 h1:c4k2FIYIh4xtwqrQwV0Ct1v5+ehlNXj5NI/MWVsiTkQ=
+github.com/Azure/azure-sdk-for-go/sdk/azcore v1.9.2/go.mod h1:5FDJtLEO/GxwNgUxbwrY3LP0pEoThTQJtk2oysdXHxM=
+github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.5.1 h1:sO0/P7g68FrryJzljemN+6GTssUXdANk6aJ7T1ZxnsQ=
+github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.5.1/go.mod h1:h8hyGFDsU5HMivxiS2iYFZsgDbU9OnnJ163x5UGVKYo=
+github.com/Azure/azure-sdk-for-go/sdk/internal v1.5.1 h1:6oNBlSdi1QqM1PNW7FPA6xOGA5UNsXnkaYZz9vdPGhA=
+github.com/Azure/azure-sdk-for-go/sdk/internal v1.5.1/go.mod h1:s4kgfzA0covAXNicZHDMN58jExvcng2mC/DepXiF1EI=
+github.com/Azure/azure-sdk-for-go/sdk/internal v1.5.2 h1:LqbJ/WzJUwBf8UiaSzgX7aMclParm9/5Vgp+TY51uBQ=
+github.com/Azure/azure-sdk-for-go/sdk/internal v1.5.2/go.mod h1:yInRyqWXAuaPrgI7p70+lDDgh3mlBohis29jGMISnmc=
+github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v1.3.1 h1:fXPMAmuh0gDuRDey0atC8cXBuKIlqCzCkL8sm1n9Ov0=
+github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v1.3.1/go.mod h1:SUZc9YRRHfx2+FAQKNDGrssXehqLpxmwRv2mC/5ntj4=
+github.com/AzureAD/microsoft-authentication-library-for-go v1.2.1 h1:DzHpqpoJVaCgOUdVHxE8QB52S6NiVdDQvGlny1qvPqA=
+github.com/AzureAD/microsoft-authentication-library-for-go v1.2.1/go.mod h1:wP83P5OoQ5p6ip3ScPr0BAq0BvuPAvacpEuSzyouqAI=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
@@ -116,6 +130,8 @@ github.com/go-gl/glfw/v3.3/glfw v0.0.0-20200222043503-6f7a984d4dc4/go.mod h1:tQ2
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
 github.com/go-test/deep v1.0.3 h1:ZrJSEWsXzPOxaZnFteGEfooLba+ju3FYIbOrS+rQd68=
 github.com/go-test/deep v1.0.3/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+github.com/golang-jwt/jwt/v5 v5.2.0 h1:d/ix8ftRUorsN+5eMIlF4T6J8CAt9rch3My2winC1Jw=
+github.com/golang-jwt/jwt/v5 v5.2.0/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/groupcache v0.0.0-20190702054246-869f871628b6/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/golang/groupcache v0.0.0-20191227052852-215e87163ea7/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
@@ -191,6 +207,10 @@ github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm4
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/uuid v1.5.0 h1:1p67kYwdtXjb0gL0BPiP1Av9wiZPo5A8z2cWkTZ+eyU=
+github.com/google/uuid v1.5.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/enterprise-certificate-proxy v0.0.0-20220520183353-fd19c99a87aa/go.mod h1:17drOmN3MwGY7t0e+Ei9b45FFGA3fBs3x36SsCg1hq8=
 github.com/googleapis/enterprise-certificate-proxy v0.1.0 h1:zO8WHNx/MYiAKJ3d5spxZXZE6KHmIQGQcAzwUzV7qQw=
 github.com/googleapis/enterprise-certificate-proxy v0.1.0/go.mod h1:17drOmN3MwGY7t0e+Ei9b45FFGA3fBs3x36SsCg1hq8=
@@ -237,6 +257,8 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kylelemons/godebug v0.0.0-20170820004349-d65d576e9348 h1:MtvEpTB6LX3vkb4ax0b5D2DHbNAUsen0Gx5wZoq3lV4=
 github.com/kylelemons/godebug v0.0.0-20170820004349-d65d576e9348/go.mod h1:B69LEHPfb2qLo0BaaOLcbitczOKLWTsrBG9LczfCD4k=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/mattn/go-colorable v0.0.9 h1:UVL0vNpWh04HeJXV0KLcaT7r06gOH2l4OW6ddYRUIY4=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-isatty v0.0.3 h1:ns/ykhmWi7G9O+8a448SecJU3nSMBXJfqQkl0upE1jI=
@@ -249,6 +271,8 @@ github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7 h1:DpOJ2HYzCv8LZP15IdmG+YdwD2luVPHITV96TkirNBM=
 github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7/go.mod h1:ZXFpozHsX6DPmq2I0TCekCxypsnAUbP2oI0UX1GXzOo=
+github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c h1:+mdjkGKdHQG3305AYmdv1U2eRNDiU2ErMBj1gwrq8eQ=
+github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c/go.mod h1:7rwL4CYBLnjLxUqIJNnCWiEdr3bn6IUYi15bNlnbCCU=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
@@ -291,6 +315,10 @@ golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.17.0 h1:r8bRNjWL3GshPW3gkd+RpvzWrZAwPS49OmTGZ/uhM4k=
+golang.org/x/crypto v0.17.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4=
+golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
+golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@@ -370,6 +398,10 @@ golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4/go.mod h1:CfG3xpIq0wQ8r1q4Su
 golang.org/x/net v0.0.0-20220607020251-c690dde0001d/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e h1:TsQ7F31D3bUCLeqPT0u+yjp1guoArKaNKmCr22PYgTQ=
 golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.19.0 h1:zTwKpTd2XuCqf8huc7Fo2iSy+4RHPd10s4KzeTnVr1c=
+golang.org/x/net v0.19.0/go.mod h1:CfAk/cbD4CthTvqiEl8NpboMuiuOYsAr/7NOjZJtv1U=
+golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
+golang.org/x/net v0.20.0/go.mod h1:z8BVo6PvndSri0LbOE3hAn0apkU+1YvI6E70E9jsnvY=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/oauth2 v0.0.0-20190604053449-0f29369cfe45/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -466,6 +498,11 @@ golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220610221304-9f5ed59c137d/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220624220833-87e55d714810 h1:rHZQSjJdAI4Xf5Qzeh2bBc5YJIkPFVM6oDtMFYmgws0=
 golang.org/x/sys v0.0.0-20220624220833-87e55d714810/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
+golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
+golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -478,6 +515,8 @@ golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7 h1:olpwvP2KacW1ZWvsR7uQhoyTYvKAupfQrRGBFM352Gk=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
+golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
@@ -727,6 +766,7 @@ gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.3/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

storage/azure/client.go

@@ -0,0 +1,63 @@
+package azure
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob"
+)
+
+type Client interface {
+	// Read an object from an Azure blob.
+	Read(ctx context.Context, container, blob string) ([]byte, error)
+
+	// Write an object onto an Azure blob.
+	Write(ctx context.Context, container, blob string, p []byte) error
+}
+
+type client struct {
+	BlobAPI *azblob.Client
+}
+
+// newClient returns a new instance of Client.
+func newClient(config *Config) (Client, error) {
+	// If the access key isn't defined in the configuration, try to read it from the environment.
+	if config.AccessKey == "" {
+		config.AccessKey = os.Getenv("TFMIGRATE_AZURERM_STORAGE_ACCESS_KEY")
+	}
+
+	cred, err := azblob.NewSharedKeyCredential(config.AccountName, config.AccessKey)
+	if err != nil {
+		return nil, err
+	}
+
+	url := fmt.Sprintf("https://%s.blob.core.windows.net/", config.AccountName)
+	c, err := azblob.NewClientWithSharedKeyCredential(url, cred, nil)
+
+	return &client{c}, err
+}
+
+// Read an object from an Azure blob.
+func (c *client) Read(ctx context.Context, container, blob string) ([]byte, error) {
+	resp, err := c.BlobAPI.DownloadStream(ctx, container, blob, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	bs := bytes.Buffer{}
+	r := resp.NewRetryReader(ctx, &azblob.RetryReaderOptions{})
+	defer r.Close()
+
+	_, err = bs.ReadFrom(r)
+
+	return bs.Bytes(), err
+}
+
+// Write an object onto an Azure blob.
+func (c *client) Write(ctx context.Context, container, blob string, p []byte) error {
+	_, err := c.BlobAPI.UploadBuffer(ctx, container, blob, p, nil)
+
+	return err
+}

storage/azure/config.go

@@ -0,0 +1,18 @@
+package azure
+
+import "github.com/minamijoyo/tfmigrate/storage"
+
+type Config struct {
+	AccessKey     string `hcl:"access_key,optional"`
+	AccountName   string `hcl:"storage_account_name"`
+	ContainerName string `hcl:"container_name"`
+	Key           string `hcl:"key"`
+}
+
+// Config implements a storage.Config.
+var _ storage.Config = (*Config)(nil)
+
+// NewStorage returns a new instance of storage.Storage.
+func (c *Config) NewStorage() (storage.Storage, error) {
+	return NewStorage(c, nil)
+}

storage/azure/config_test.go

@@ -0,0 +1,46 @@
+package azure
+
+import "testing"
+
+func TestConfigNewStorage(t *testing.T) {
+	cases := []struct {
+		desc   string
+		config *Config
+		ok     bool
+	}{
+		{
+			desc: "valid",
+			config: &Config{
+				AccountName:   "tfmigrate-test",
+				ContainerName: "tfmigrate",
+				Key:           "history.json",
+			},
+			ok: true,
+		},
+		{
+			desc: "valid",
+			config: &Config{
+				AccessKey:     "ZHVtbXkK", // expected to be a base64-encoded string
+				AccountName:   "tfmigrate-test",
+				ContainerName: "tfmigrate",
+				Key:           "history.json",
+			},
+			ok: true,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.desc, func(t *testing.T) {
+			got, err := tc.config.NewStorage()
+			if tc.ok && err != nil {
+				t.Fatalf("unexpected err: %s", err)
+			}
+			if !tc.ok && err == nil {
+				t.Fatalf("expected to return an error, but no error, got: %#v", got)
+			}
+			if tc.ok {
+				_ = got.(*Storage)
+			}
+		})
+	}
+}