feat: implement stackit git instances (#791)

* feat: implement stackit git instances

* review changes

stackit/internal/services/git/instance/datasource.go

@@ -0,0 +1,162 @@
+package instance
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/hashicorp/terraform-plugin-framework/datasource"
+	"github.com/hashicorp/terraform-plugin-framework/datasource/schema"
+	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
+	"github.com/hashicorp/terraform-plugin-log/tflog"
+	"github.com/stackitcloud/stackit-sdk-go/core/config"
+	"github.com/stackitcloud/stackit-sdk-go/core/oapierror"
+	"github.com/stackitcloud/stackit-sdk-go/services/git"
+	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/core"
+	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/features"
+	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/validate"
+)
+
+// Ensure the implementation satisfies the expected interfaces.
+var (
+	_ datasource.DataSource = &gitDataSource{}
+)
+
+// NewGitDataSource creates a new instance of the gitDataSource.
+func NewGitDataSource() datasource.DataSource {
+	return &gitDataSource{}
+}
+
+// gitDataSource is the datasource implementation.
+type gitDataSource struct {
+	client *git.APIClient
+}
+
+// Configure sets up the API client for the git instance resource.
+func (g *gitDataSource) Configure(ctx context.Context, req datasource.ConfigureRequest, resp *datasource.ConfigureResponse) {
+	// Prevent potential panics if the provider is not properly configured.
+	if req.ProviderData == nil {
+		return
+	}
+
+	// Validate provider data type before proceeding.
+	providerData, ok := req.ProviderData.(core.ProviderData)
+	if !ok {
+		core.LogAndAddError(ctx, &resp.Diagnostics, "Error configuring API client", fmt.Sprintf("Expected configure type stackit.ProviderData, got %T", req.ProviderData))
+		return
+	}
+
+	features.CheckBetaResourcesEnabled(ctx, &providerData, &resp.Diagnostics, "stackit_git", "datasource")
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	// Initialize the API client with the appropriate authentication and endpoint settings.
+	var apiClient *git.APIClient
+	var err error
+	if providerData.GitCustomEndpoint != "" {
+		apiClient, err = git.NewAPIClient(
+			config.WithCustomAuth(providerData.RoundTripper),
+			config.WithEndpoint(providerData.GitCustomEndpoint),
+		)
+	} else {
+		apiClient, err = git.NewAPIClient(
+			config.WithCustomAuth(providerData.RoundTripper),
+		)
+	}
+
+	// Handle API client initialization errors.
+	if err != nil {
+		core.LogAndAddError(ctx, &resp.Diagnostics, "Error configuring API client", fmt.Sprintf("Configuring client: %v. This is an error related to the provider configuration, not to the resource configuration", err))
+		return
+	}
+
+	// Store the initialized client.
+	g.client = apiClient
+	tflog.Info(ctx, "git client configured")
+}
+
+// Metadata provides metadata for the git datasource.
+func (g *gitDataSource) Metadata(_ context.Context, req datasource.MetadataRequest, resp *datasource.MetadataResponse) {
+	resp.TypeName = req.ProviderTypeName + "_git"
+}
+
+// Schema defines the schema for the git data source.
+func (g *gitDataSource) Schema(_ context.Context, _ datasource.SchemaRequest, resp *datasource.SchemaResponse) {
+	resp.Schema = schema.Schema{
+		MarkdownDescription: features.AddBetaDescription("Git Instance datasource schema."),
+		Description:         "Git Instance datasource schema.",
+		Attributes: map[string]schema.Attribute{
+			"id": schema.StringAttribute{
+				Description: descriptions["id"],
+				Computed:    true,
+			},
+			"project_id": schema.StringAttribute{
+				Description: descriptions["project_id"],
+				Required:    true,
+				Validators: []validator.String{
+					validate.UUID(),
+					validate.NoSeparator(),
+				},
+			},
+			"instance_id": schema.StringAttribute{
+				Description: descriptions["instance_id"],
+				Required:    true,
+				Validators: []validator.String{
+					validate.UUID(),
+					validate.NoSeparator(),
+				},
+			},
+			"name": schema.StringAttribute{
+				Description: descriptions["name"],
+				Computed:    true,
+			},
+			"url": schema.StringAttribute{
+				Description: descriptions["url"],
+				Computed:    true,
+			},
+			"version": schema.StringAttribute{
+				Description: descriptions["version"],
+				Computed:    true,
+			},
+		},
+	}
+}
+
+func (g *gitDataSource) Read(ctx context.Context, req datasource.ReadRequest, resp *datasource.ReadResponse) { // nolint:gocritic // function signature required by Terraform
+	var model Model
+	diags := req.Config.Get(ctx, &model)
+	resp.Diagnostics.Append(diags...)
+	if resp.Diagnostics.HasError() {
+		return
+	}
+
+	// Extract the project ID and instance id of the model
+	projectId := model.ProjectId.ValueString()
+	instanceId := model.InstanceId.ValueString()
+
+	// Read the current git instance via id
+	gitInstanceResp, err := g.client.GetInstance(ctx, projectId, instanceId).Execute()
+	if err != nil {
+		var oapiErr *oapierror.GenericOpenAPIError
+		ok := errors.As(err, &oapiErr)
+		if ok && oapiErr.StatusCode == http.StatusNotFound {
+			resp.State.RemoveResource(ctx)
+			return
+		}
+		core.LogAndAddError(ctx, &resp.Diagnostics, "Error reading git instance", fmt.Sprintf("Calling API: %v", err))
+		return
+	}
+
+	err = mapFields(gitInstanceResp, &model)
+	if err != nil {
+		core.LogAndAddError(ctx, &resp.Diagnostics, "Error reading git instance", fmt.Sprintf("Processing API response: %v", err))
+		return
+	}
+
+	// Set the updated state.
+	diags = resp.State.Set(ctx, &model)
+	resp.Diagnostics.Append(diags...)
+	tflog.Info(ctx, fmt.Sprintf("read git instance %s", instanceId))
+}