feat(provider): choose between constant & exponential backoff for act…

…ions (#798)

Adds an option `poll_function` to decide between constant & exponential backoff
while waiting for actions to finish.

The default is the previous behaviour of the exponential backoff.

hcloud/plugin_provider.go

@@ -7,11 +7,13 @@ import (
 	"time"
 
 	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/terraform-plugin-framework-validators/stringvalidator"
 	"github.com/hashicorp/terraform-plugin-framework/datasource"
 	"github.com/hashicorp/terraform-plugin-framework/path"
 	"github.com/hashicorp/terraform-plugin-framework/provider"
 	"github.com/hashicorp/terraform-plugin-framework/provider/schema"
 	"github.com/hashicorp/terraform-plugin-framework/resource"
+	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
 	"github.com/hashicorp/terraform-plugin-framework/types"
 	"github.com/hashicorp/terraform-plugin-log/tflog"
 
@@ -56,6 +58,13 @@ func (p *PluginProvider) Schema(_ context.Context, _ provider.SchemaRequest, res
 				Description: "The interval at which actions are polled by the client. Default `500ms`. Increase this interval if you run into rate limiting errors.",
 				Optional:    true,
 			},
+			"poll_function": schema.StringAttribute{
+				Description: "The type of function to be used during the polling.",
+				Optional:    true,
+				Validators: []validator.String{
+					stringvalidator.OneOf([]string{"constant", "exponential"}...),
+				},
+			},
 		},
 		// TODO: Uncomment once we get rid of the SDK v2 Provider
 		// MarkdownDescription: `The Hetzner Cloud (hcloud) provider is used to interact with the resources supported by
@@ -69,6 +78,7 @@ type PluginProviderModel struct {
 	Token        types.String `tfsdk:"token"`
 	Endpoint     types.String `tfsdk:"endpoint"`
 	PollInterval types.String `tfsdk:"poll_interval"`
+	PollFunction types.String `tfsdk:"poll_function"`
 }
 
 // Configure is called at the beginning of the provider lifecycle, when
@@ -121,7 +131,11 @@ func (p *PluginProvider) Configure(ctx context.Context, req provider.ConfigureRe
 				fmt.Sprintf("An unexpected error was encountered trying to parse the value.\n\n%s", err.Error()),
 			)
 		}
-		opts = append(opts, hcloud.WithPollBackoffFunc(hcloud.ExponentialBackoff(2, pollInterval)))
+		if data.PollFunction.ValueString() == "constant" {
+			opts = append(opts, hcloud.WithPollBackoffFunc(hcloud.ConstantBackoff(pollInterval)))
+		} else {
+			opts = append(opts, hcloud.WithPollBackoffFunc(hcloud.ExponentialBackoff(2, pollInterval)))
+		}
 	}
 
 	if resp.Diagnostics.HasError() {

hcloud/provider.go

@@ -16,6 +16,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/logging"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 	"github.com/hetznercloud/hcloud-go/hcloud"
@@ -68,6 +69,13 @@ func Provider() *schema.Provider {
 				Default:     "500ms",
 				Description: "The interval at which actions are polled by the client. Default `500ms`. Increase this interval if you run into rate limiting errors.",
 			},
+			"poll_function": {
+				Type:         schema.TypeString,
+				Optional:     true,
+				Default:      "exponential",
+				Description:  "The type of function to be used during the polling.",
+				ValidateFunc: validation.StringInSlice([]string{"constant", "exponential"}, false),
+			},
 		},
 		ResourcesMap: map[string]*schema.Resource{
 			certificate.UploadedResourceType:  certificate.UploadedResource(),
@@ -139,7 +147,12 @@ func providerConfigure(_ context.Context, d *schema.ResourceData) (interface{},
 		if err != nil {
 			return nil, hcclient.ErrorToDiag(err)
 		}
-		opts = append(opts, hcloud.WithPollBackoffFunc(hcloud.ExponentialBackoff(2, pollInterval)))
+		pollFunction, ok := d.GetOk("poll_function")
+		if ok && pollFunction == "constant" {
+			opts = append(opts, hcloud.WithPollBackoffFunc(hcloud.ConstantBackoff(pollInterval)))
+		} else {
+			opts = append(opts, hcloud.WithPollBackoffFunc(hcloud.ExponentialBackoff(2, pollInterval)))
+		}
 	}
 	if logging.LogLevel() != "" {
 		opts = append(opts, hcloud.WithDebugWriter(log.Writer()))

website/docs/index.html.markdown

@@ -38,7 +38,8 @@ The following arguments are supported:
 
 - `token` - (Required, string) This is the Hetzner Cloud API Token, can also be specified with the `HCLOUD_TOKEN` environment variable.
 - `endpoint` - (Optional, string) Hetzner Cloud API endpoint, can be used to override the default API Endpoint `https://api.hetzner.cloud/v1`.
-- `poll_interval` -  (Optional, string) Configures the interval in which actions are polled by the client. Default `500ms`. Increase this interval if you run into rate limiting errors.
+- `poll_interval` - (Optional, string) Configures the interval in which actions are polled by the client. Default `500ms`. Increase this interval if you run into rate limiting errors.
+- `poll_function` - (Optional, string) Configures the type of function to be used during the polling. Valid values are `constant` and `exponential`. Default `exponential`.
 
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