feat: support provider-level host configuration

This seeks to address issue #34 by offering the ability to specify
provider-level host configuration & host-specific request headers.

Signed-off-by: Mike Ball <[email protected]>

Author: mdb

docs/index.md

@@ -10,4 +10,27 @@ The HTTP provider is a utility provider for interacting with generic HTTP
 servers as part of a Terraform configuration.
 
 This provider requires no configuration. For information on the resources
-it provides, see the navigation bar.
+it provides, see the navigation bar.
+
+<!-- schema generated by tfplugindocs -->
+## Schema
+
+### Optional
+
+- `host` (Block List) A host-specific provider configuration. (see [below for nested schema](#nestedblock--host))
+
+<a id="nestedblock--host"></a>
+### Nested Schema for `host`
+
+Required:
+
+- `name` (String) The hostname for which the host configuration should
+take affect. If the name matches an HTTP request URL's hostname, the provider's
+host configuration takes affect (in addition to any data- or resource-specific
+request configuration.
+
+Optional:
+
+- `request_headers` (Map of String, Sensitive) A map of request header field names and values to
+include in HTTP requests if/when the request URL's hostname matches the provider
+host configuration name.

internal/provider/data_source_http.go

@@ -37,7 +37,9 @@ func NewHttpDataSource() datasource.DataSource {
 	return &httpDataSource{}
 }
 
-type httpDataSource struct{}
+type httpDataSource struct {
+	provider *httpProvider
+}
 
 func (d *httpDataSource) Metadata(_ context.Context, _ datasource.MetadataRequest, resp *datasource.MetadataResponse) {
 	// This data source name unconventionally is equal to the provider name,
@@ -47,6 +49,10 @@ func (d *httpDataSource) Metadata(_ context.Context, _ datasource.MetadataReques
 	resp.TypeName = "http"
 }
 
+func (d *httpDataSource) Configure(_ context.Context, req datasource.ConfigureRequest, resp *datasource.ConfigureResponse) {
+	d.provider, resp.Diagnostics = toProvider(req.ProviderData)
+}
+
 func (d *httpDataSource) Schema(ctx context.Context, req datasource.SchemaRequest, resp *datasource.SchemaResponse) {
 	resp.Schema = schema.Schema{
 		Description: `
@@ -350,6 +356,24 @@ func (d *httpDataSource) Read(ctx context.Context, req datasource.ReadRequest, r
 		}
 	}
 
+	parsedRequestURL, err := url.Parse(requestURL)
+	if err != nil {
+		resp.Diagnostics.AddError(
+			"Error parsing URL",
+			"An unexpected error occurred while parsing the request URL: "+err.Error(),
+		)
+		return
+	}
+
+	if d.provider.Hostname == parsedRequestURL.Hostname() {
+		for name, header := range d.provider.RequestHeaders {
+			request.Header.Set(name, header)
+			if strings.ToLower(name) == "host" {
+				request.Host = header
+			}
+		}
+	}
+
 	response, err := retryClient.Do(request)
 	if err != nil {
 		target := &url.Error{}

internal/provider/data_source_http_test.go

@@ -149,6 +149,89 @@ func TestDataSource_withAuthorizationRequestHeader_200(t *testing.T) {
 	})
 }
 
+func TestDataSource_withAuthorizationRequestHeaderFromProvider_200(t *testing.T) {
+	testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Header.Get("Authorization") == "Zm9vOmJhcg==" {
+			w.Header().Set("Content-Type", "text/plain")
+			_, err := w.Write([]byte("1.0.0"))
+			if err != nil {
+				t.Errorf("error writing body: %s", err)
+			}
+		} else {
+			w.WriteHeader(http.StatusForbidden)
+		}
+	}))
+	defer testServer.Close()
+
+	testServerURL, _ := url.Parse(testServer.URL)
+	testServerHostname := testServerURL.Hostname()
+
+	resource.ParallelTest(t, resource.TestCase{
+		ProtoV5ProviderFactories: protoV5ProviderFactories(),
+		Steps: []resource.TestStep{
+			{
+				Config: fmt.Sprintf(`
+							provider "http" {
+								host {
+									name = "%s"
+									request_headers = {
+										"Authorization" = "Zm9vOmJhcg=="
+									}
+								}
+							}
+							data "http" "http_test" {
+								url = "%s"
+							}`, testServerHostname, testServer.URL),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("data.http.http_test", "response_body", "1.0.0"),
+					resource.TestCheckResourceAttr("data.http.http_test", "status_code", "200"),
+					resource.TestCheckNoResourceAttr("data.http.http_test", "request_headers"),
+				),
+			},
+		},
+	})
+}
+
+func TestDataSource_withDifferentHostnameFromProvider_403(t *testing.T) {
+	testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Header.Get("Authorization") == "Zm9vOmJhcg==" {
+			w.Header().Set("Content-Type", "text/plain")
+			_, err := w.Write([]byte("1.0.0"))
+			if err != nil {
+				t.Errorf("error writing body: %s", err)
+			}
+		} else {
+			w.WriteHeader(http.StatusForbidden)
+		}
+	}))
+	defer testServer.Close()
+
+	resource.ParallelTest(t, resource.TestCase{
+		ProtoV5ProviderFactories: protoV5ProviderFactories(),
+		Steps: []resource.TestStep{
+			{
+				Config: fmt.Sprintf(`
+							provider "http" {
+								host {
+									name = "host.com"
+									request_headers = {
+										"Authorization" = "Zm9vOmJhcg=="
+									}
+								}
+							}
+							data "http" "http_test" {
+								url = "%s"
+							}`, testServer.URL),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("data.http.http_test", "response_body", ""),
+					resource.TestCheckResourceAttr("data.http.http_test", "status_code", "403"),
+					resource.TestCheckNoResourceAttr("data.http.http_test", "request_headers"),
+				),
+			},
+		},
+	})
+}
+
 func TestDataSource_withAuthorizationRequestHeader_403(t *testing.T) {
 	testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Header.Get("Authorization") != "Zm9vOmJhcg==" {

internal/provider/provider.go

@@ -5,28 +5,145 @@ package provider
 
 import (
 	"context"
+	"fmt"
 
+	"github.com/hashicorp/terraform-plugin-framework-validators/listvalidator"
 	"github.com/hashicorp/terraform-plugin-framework/datasource"
+	"github.com/hashicorp/terraform-plugin-framework/diag"
+	"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/tfsdk"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-log/tflog"
 )
 
+type httpProviderConfig struct {
+}
+
+type httpProvider struct {
+	Hostname       string
+	RequestHeaders map[string]string
+}
+
+var _ provider.Provider = (*httpProvider)(nil)
+
 func New() provider.Provider {
 	return &httpProvider{}
 }
 
-var _ provider.Provider = (*httpProvider)(nil)
+type httpProviderConfigModel struct {
+	Host types.List `tfsdk:"host"`
+}
 
-type httpProvider struct{}
+type httpProviderHostConfigModel struct {
+	Name           types.String `tfsdk:"name"`
+	RequestHeaders types.Map    `tfsdk:"request_headers"`
+}
 
 func (p *httpProvider) Metadata(_ context.Context, _ provider.MetadataRequest, resp *provider.MetadataResponse) {
 	resp.TypeName = "http"
 }
 
-func (p *httpProvider) Schema(context.Context, provider.SchemaRequest, *provider.SchemaResponse) {
+func (p *httpProvider) Schema(_ context.Context, _ provider.SchemaRequest, resp *provider.SchemaResponse) {
+	resp.Schema = schema.Schema{
+		Description: "Configures the HTTP provider",
+		Blocks: map[string]schema.Block{
+			"host": schema.ListNestedBlock{
+				Description: "A host-specific provider configuration.",
+				Validators: []validator.List{
+					listvalidator.SizeBetween(0, 1),
+				},
+				NestedObject: schema.NestedBlockObject{
+					Attributes: map[string]schema.Attribute{
+						"name": schema.StringAttribute{
+							Description: `The hostname for which the host configuration should
+take affect. If the name matches an HTTP request URL's hostname, the provider's
+host configuration takes affect (in addition to any data- or resource-specific
+request configuration.`,
+							Required: true,
+						},
+						"request_headers": schema.MapAttribute{
+							Description: `A map of request header field names and values to
+include in HTTP requests if/when the request URL's hostname matches the provider
+host configuration name.`,
+							ElementType: types.StringType,
+							Optional:    true,
+							Sensitive:   true,
+						},
+					},
+				},
+			},
+		},
+	}
 }
 
-func (p *httpProvider) Configure(context.Context, provider.ConfigureRequest, *provider.ConfigureResponse) {
+func (p *httpProvider) Configure(ctx context.Context, req provider.ConfigureRequest, res *provider.ConfigureResponse) {
+	tflog.Debug(ctx, "Configuring provider")
+	//p.resetConfig()
+
+	// Ensure these response values are set before early returns, etc.
+	res.DataSourceData = p
+	res.ResourceData = p
+
+	// Load configuration into the model
+	var conf httpProviderConfigModel
+	res.Diagnostics.Append(req.Config.Get(ctx, &conf)...)
+	if res.Diagnostics.HasError() {
+		return
+	}
+	if conf.Host.IsNull() || conf.Host.IsUnknown() || len(conf.Host.Elements()) == 0 {
+		tflog.Debug(ctx, "No host configuration detected; using provider defaults")
+		return
+	}
+
+	// Load proxy configuration into model
+	hostConfSlice := make([]httpProviderHostConfigModel, 1)
+	res.Diagnostics.Append(conf.Host.ElementsAs(ctx, &hostConfSlice, true)...)
+	if res.Diagnostics.HasError() {
+		return
+	}
+	if len(hostConfSlice) != 1 {
+		res.Diagnostics.AddAttributeError(
+			path.Root("host"),
+			"Provider Proxy Configuration Handling Error",
+			"The provider failed to fully load the expected host configuration. "+
+				"This is likely a bug in the Terraform Provider and should be reported to the provider developers.",
+		)
+		return
+	}
+	hostConf := hostConfSlice[0]
+	tflog.Debug(ctx, "Loaded provider configuration")
+
+	// Parse the host name
+	if !hostConf.Name.IsNull() && !hostConf.Name.IsUnknown() {
+		tflog.Debug(ctx, "Configuring host via name", map[string]interface{}{
+			"name": hostConf.Name.ValueString(),
+		})
+
+		p.Hostname = hostConf.Name.ValueString()
+	}
+
+	if !hostConf.RequestHeaders.IsNull() && !hostConf.RequestHeaders.IsUnknown() {
+		tflog.Debug(ctx, "Configuring request headers")
+		requestHeaders := map[string]string{}
+		for name, value := range hostConf.RequestHeaders.Elements() {
+			var header string
+			diags := tfsdk.ValueAs(ctx, value, &header)
+			res.Diagnostics.Append(diags...)
+			if res.Diagnostics.HasError() {
+				return
+			}
+
+			requestHeaders[name] = header
+		}
+
+		p.RequestHeaders = requestHeaders
+	}
+
+	tflog.Debug(ctx, "Provider configured")
 }
 
 func (p *httpProvider) Resources(context.Context) []func() resource.Resource {
@@ -38,3 +155,25 @@ func (p *httpProvider) DataSources(context.Context) []func() datasource.DataSour
 		NewHttpDataSource,
 	}
 }
+
+// toProvider casts a generic provider.Provider reference to this specific provider.
+// This can be used in DataSourceType.NewDataSource and ResourceType.NewResource calls.
+func toProvider(in any) (*httpProvider, diag.Diagnostics) {
+	if in == nil {
+		return nil, nil
+	}
+
+	var diags diag.Diagnostics
+	p, ok := in.(*httpProvider)
+	if !ok {
+		diags.AddError(
+			"Unexpected Provider Instance Type",
+			fmt.Sprintf("While creating the data source or resource, an unexpected provider type (%T) was received. "+
+				"This is likely a bug in the provider code and should be reported to the provider developers.", in,
+			),
+		)
+		return nil, diags
+	}
+
+	return p, diags
+}