package cloud

import "gocloud.dev"

Package cloud contains a library and tools for open cloud development in Go.

The Go Cloud Development Kit (Go CDK) allows application developers to seamlessly deploy cloud applications on any combination of cloud providers. It does this by providing stable, idiomatic interfaces for common uses like storage and databases. Think `database/sql` for cloud products.

At the core of the Go CDK are common "portable types" implemented by cloud providers. For example, objects of the blob.Bucket portable type can be created using gcsblob.OpenBucket, s3blob.OpenBucket, or any other provider. Then, the blob.Bucket can be used throughout your application without worrying about the underlying implementation.

The Go CDK works well with a code generator called Wire (https://github.com/google/wire/blob/master/README.md). It creates human-readable code that only imports the cloud SDKs for providers you use. This allows the Go CDK to grow to support any number of cloud providers, without increasing compile times or binary sizes, and avoiding any side effects from `init()` functions.

For sample applications and a tutorial, see the samples directory (https://github.com/google/go-cloud/tree/master/samples).

URLs ¶

In addition to creating portable types via provider-specific constructors (e.g., creating a blob.Bucket using s3blob.OpenBucket), many portable types can also be created using a URL. The scheme of the URL specifies the provider, and each provider implementation has code to convert the URL into the data needed to call its constructor. For example, calling blob.OpenBucket with s3blob://my-bucket will return a blob.Bucket created using s3blob.OpenBucket.

Each portable API package will document the types that it supports opening by URL; for example, the blob package supports Buckets, while the pubsub package supports Topics and Subscriptions. Each provider implementation will document what scheme(s) it registers for, and what format of URL it expects.

Each portable type URL opener will accept URL schemes with an <api>+ prefix (e.g., blob+file:///dir" instead of "file:///dir", as well as schemes with an <api>+<type>+ prefix (e.g., blob+bucket+file:///dir).

Each portable API package should include an example using a URL, and many providers will include provider-specific examples as well.

URL Muxes ¶

Each portable type that's openable via URL will have a top-level function you can call, like blob.OpenBucket. This top-level function uses a default instance of an URLMux multiplexer to map schemes to a provider-specific opener for the type. For example, blob has a BucketURLOpener interface that providers implement and then register using RegisterBucket.

Many applications will work just fine using the default mux through the top-level Open functions. However, if you want more control, you can create your own URLMux and register the provider URLOpeners you need. Most providers will export URLOpeners that give you more fine grained control over the arguments needed by the constructor. In particular, portable types opened via URL will often use default credentials from the environment. For example, the AWS URL openers use the credentials saved by "aws login" (we don't want to include credentials in the URL itself, since they are likely to be sensitive).

- Instantiate the provider's URLOpener with the specific fields you need.
  For example, s3blob.URLOpener{ConfigProvider: myAWSProvider} using a
  ConfigProvider that holds explicit AWS credentials.
- Create your own instance of the URLMux, e.g., mymux := new(blob.URLMux).
- Register your custom URLOpener on your mux, e.g.,
  mymux.RegisterBucket(s3blob.Scheme, myS3URLOpener).
- Now use your mux to open URLs, e.g. mymux.OpenBucket('s3://my-bucket').

Escaping the abstraction ¶

It is not feasible or desirable for APIs like blob.Bucket to encompass the full functionality of every provider. Rather, we intend to provide a subset of the most commonly used functionality. There will be cases where a developer wants to access provider-specific functionality, such as unexposed APIs or data fields, errors or options. This can be accomplished using As functions.

As ¶

As functions in the APIs provide the user a way to escape the Go CDK abstraction to access provider-specific types. They might be used as an interim solution until a feature request to the Go CDK is implemented. Or, the Go CDK may choose not to support specific features, and the use of As will be permanent.

Using As implies that the resulting code is no longer portable; the provider-specific code will need to be ported in order to switch providers. Therefore, it should be avoided if possible.

Each API will include examples demonstrating how to use its various As functions, and each provider implementation will document what types it supports for each.

Usage:

1. Declare a variable of the provider-specific type you want to access.

2. Pass a pointer to it to As.

3. If the type is supported, As will return true and copy the provider-specific type into your variable. Otherwise, it will return false.

Provider-specific types that are intended to be mutable will be exposed as a pointer to the underlying type.

Index ¶

Package Files ¶

doc.go

Directories ¶

Path	Synopsis
aws	Package aws provides fundamental Wire providers for Amazon Web Services (AWS).
aws/awscloud	Package awscloud contains Wire providers for AWS services.
aws/rds	Package rds contains Wire providers that are common across RDS.
azure/azurecloud	Package azurecloud contains Wire providers for Azure services.
blob	Package blob provides an easy and portable way to interact with blobs within a storage location, hereafter called a "bucket".
blob/azureblob	Package azureblob provides a blob implementation that uses Azure Storage’s BlockBlob.
blob/driver	Package driver defines a set of interfaces that the blob package uses to interact with the underlying blob services.
blob/drivertest	Package drivertest provides a conformance test for implementations of driver.
blob/fileblob	Package fileblob provides a blob implementation that uses the filesystem.
blob/gcsblob	Package gcsblob provides a blob implementation that uses GCS.
blob/memblob	Package memblob provides an in-memory blob implementation.
blob/s3blob	Package s3blob provides a blob implementation that uses S3.
gcerrors	Package gcerrors provides support for getting error codes from errors returned by Go CDK APIs.
gcp	Package gcp provides fundamental Wire providers and types for Google Cloud Platform (GCP).
gcp/cloudsql	Package cloudsql contains Wire providers that are common across Google Cloud SQL.
gcp/gcpcloud	Package gcpcloud contains Wire providers for GCP services.
health	Package health provides health check handlers.
health/sqlhealth	Package sqlhealth provides a health check for a SQL database connection.
internal/batcher	Package batcher supports batching of items.
internal/contributebot	contributebot is a service for keeping the Go Cloud Development Kit project tidy.
internal/docstore	Package docstore provides a portable implementation of a document store.
internal/docstore/driver	Package driver defines a set of interfaces that the docstore package uses to interact with the underlying services.
internal/docstore/drivertest	Package drivertest provides a conformance test for implementations of driver.
internal/docstore/memdocstore	Package memdocstore provides an in-memory implementation of the docstore API.
internal/escape	Package escape includes helpers for escaping and unescaping strings.
internal/gcerr	Package gcerr provides an error type for Go CDK APIs.
internal/oc	Package oc supports OpenCensus tracing and metrics for the Go Cloud Development Kit.
internal/retry	Package retry provides retry logic.
internal/testing/octest	Package octest supports testing of OpenCensus integrations.
internal/testing/replay	Package replay provides the ability to record and replay HTTP requests.
internal/testing/setup
internal/testing/terraform	Package terraform provides a function to read Terraform output.
internal/trace	Package trace provides support for OpenCensus tracing.
internal/useragent	Package useragent includes constants and utilitiesfor setting the User-Agent for Go CDK connections to GCP.
mysql/cloudmysql	Package cloudmysql provides connections to managed MySQL Cloud SQL instances.
mysql/rdsmysql	Package rdsmysql provides connections to AWS RDS MySQL instances.
postgres/cloudpostgres	Package cloudpostgres provides connections to managed PostgreSQL Cloud SQL instances.
postgres/rdspostgres	Package rdspostgres provides connections to AWS RDS PostgreSQL instances.
pubsub	Package pubsub provides an easy and portable way to interact with publish/ subscribe systems.
pubsub/awspubsub	Package awspubsub provides an implementation of pubsub that uses AWS SNS (Simple Notification Service) and SQS (Simple Queueing Service).
pubsub/azurepubsub	Package azurepubsub provides an implementation of pubsub using Azure Service Bus Topic and Subscription.
pubsub/driver	Package driver defines a set of interfaces that the pubsub package uses to interact with the underlying pubsub services.
pubsub/drivertest	Package drivertest provides a conformance test for implementations of driver.
pubsub/gcppubsub	Package gcppubsub provides a pubsub implementation that uses GCP PubSub.
pubsub/mempubsub	Package mempubsub provides an in-memory pubsub implementation.
pubsub/rabbitpubsub	Package rabbitpubsub provides an pubsub implementation for RabbitMQ.
requestlog	Package requestlog provides an http.Handler that logs information about requests.
runtimevar	Package runtimevar provides an easy and portable way to watch runtime configuration variables.
runtimevar/blobvar	Package blobvar provides a runtimevar implementation with variables read from a blob.Bucket.
runtimevar/constantvar	Package constantvar provides a runtimevar implementation with Variables that never change.
runtimevar/driver	Package driver provides the interface for providers of runtimevar.
runtimevar/drivertest	Package drivertest provides a conformance test for implementations of runtimevar.
runtimevar/etcdvar	Package etcdvar provides a runtimevar implementation with variables backed by etcd.
runtimevar/filevar	Package filevar provides a runtimevar implementation with variables backed by the filesystem.
runtimevar/paramstore	Package paramstore provides a runtimevar implementation with variables read from AWS Systems Manager Parameter Store (https://docs.aws.amazon.com/systems-manager/latest/userguide/systems-manager-paramstore.html) Use NewVariable to construct a *runtimevar.Variable.
runtimevar/runtimeconfigurator	Package runtimeconfigurator provides a runtimevar implementation with variables read from GCP Cloud Runtime Configurator (https://cloud.google.com/deployment-manager/runtime-configurator).
secrets	Package secrets provides an easy and portable way to encrypt and decrypt messages.
secrets/awskms	Package awskms provides a secrets implementation backed by AWS KMS.
secrets/driver	Package driver defines interfaces to be implemented for providers of the secrets package.
secrets/drivertest	Package drivertest provides a conformance test for implementations of the secrets driver.
secrets/gcpkms	Package gcpkms provides a secrets implementation backed by Google Cloud KMS.
secrets/localsecrets	Package localsecrets provides a secrets implementation using a locally locally provided symmetric key.
secrets/vault	Package vault provides a secrets implementation using the Transit Secrets Engine of Vault by Hashicorp.
server	Package server provides a preconfigured HTTP server with diagnostic hooks.
server/driver	Package driver defines an interface for custom HTTP listeners.
server/sdserver	Package sdserver provides the diagnostic hooks for a server using Stackdriver.
server/xrayserver	Package xrayserver provides the diagnostic hooks for a server using AWS X-Ray.