feat: support nexus api-version header

Updated the Go SDK to set the `API-Version` header to the Nexus OpenAPI
specification version when making API requests.

Closes SSE-61.

Author: sudomateo

.github/ISSUE_TEMPLATE/release_checklist.md

@@ -11,12 +11,12 @@ labels: release
  After completing each task put an `x` in the corresponding box,
  and paste the link to the relevant PR.
 -->
-- [ ] Make sure the [VERSION](https://github.com/oxidecomputer/oxide.go/blob/main/VERSION) and [oxide/version.go](https://github.com/oxidecomputer/oxide.go/blob/main/oxide/version.go) files have the new version you want to release.
+- [ ] Make sure the [VERSION](https://github.com/oxidecomputer/oxide.go/blob/main/VERSION) and [internal/generate/version.go](https://github.com/oxidecomputer/oxide.go/blob/main/internal/generate/version.go) files have the new version you want to release.
 - [ ] Make sure the changelog file in the `.changelog/` directory is set to the new version you want to release.
 - [ ] Make sure all examples and docs reference the new version.
 - [ ] Make sure you've pulled the latest tag on main, and generate changelog by running `make changelog`. Add the date of the release to the title, and update associated Oxide API version.
 - [ ] Release the new version by running `make tag`.
 - [ ] Update GitHub release description with release notes generated from `make changelog`.
 - [ ] Create a release branch from the commit of the release tag.
-- [ ] Bump the version in [VERSION](https://github.com/oxidecomputer/oxide.go/blob/main/VERSION) and [oxide/version.go](https://github.com/oxidecomputer/oxide.go/blob/main/oxide/version.go).
+- [ ] Bump the version in [VERSION](https://github.com/oxidecomputer/oxide.go/blob/main/VERSION) and [internal/generate/version.go](https://github.com/oxidecomputer/oxide.go/blob/main/internal/generate/version.go).
 - [ ] Create a new file for the next release in [.changelog/](https://github.com/oxidecomputer/oxide.go/blob/main/.changelog/).

CONTRIBUTING.md

@@ -18,7 +18,7 @@ $ make all
 
 1. Make sure the following files have the new version you want to release.
    - [`VERSION`](./VERSION)
-   - [`oxide/version.go`](./oxide/version.go)
+   - [`oxide/version.go`](./oxide/version.go): Updated via [`internal/generate/version.go`](./internal/generate/version.go)
 2. Make sure you have run `make all` and pushed any changes. The release
    will fail if running `make all` causes any changes to the generated
    code.

internal/generate/main.go

@@ -59,6 +59,11 @@ func generateSDK() error {
 		return err
 	}
 
+	versionFile := "../../oxide/version.go"
+	if err := generateVersion(versionFile, spec); err != nil {
+		return err
+	}
+
 	return nil
 }
 

internal/generate/templates/version.tpl

@@ -0,0 +1,11 @@
+// sdkVersion is the Oxide Go SDK sdkVersion. This is used to dynamically
+// populate the user agent for [Client]. It is purposefully unexported to
+// prevent external users from reading it. This must be changed along with the
+// VERSION file in the root of this repository.
+const sdkVersion = "{{ .SDKVersion }}"
+
+// openAPIVersion is the OpenAPI specification version the Oxide Go SDK was
+// generated from. This is used to dynamically populate the 'API-Version' header
+// for [Client]. It is purposefully unexported to prevent external users from
+// reading it.
+const openAPIVersion = "{{ .OpenAPIVersion }}"

internal/generate/version.go

@@ -0,0 +1,48 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"fmt"
+	"text/template"
+
+	"github.com/getkin/kin-openapi/openapi3"
+)
+
+// generateVersion generates the version.go file with both SDK and API versions.
+func generateVersion(file string, spec *openapi3.T) error {
+	f, err := openGeneratedFile(file)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	apiVersion := ""
+	if spec.Info != nil && spec.Info.Version != "" {
+		apiVersion = spec.Info.Version
+	}
+	if apiVersion == "" {
+		return fmt.Errorf("failed generating %s: api version cannnot be empty", file)
+	}
+
+	t, err := template.ParseFiles("./templates/version.tpl")
+	if err != nil {
+		return fmt.Errorf("failed generating %s: %w", file, err)
+	}
+
+	data := struct {
+		SDKVersion     string
+		OpenAPIVersion string
+	}{
+		SDKVersion:     "v0.8.0",
+		OpenAPIVersion: apiVersion,
+	}
+
+	if err := t.Execute(f, data); err != nil {
+		return fmt.Errorf("failed generating %s: %w", file, err)
+	}
+
+	return nil
+}

oxide/lib.go

@@ -194,7 +194,7 @@ func NewClient(cfg *Config) (*Client, error) {
 
 // defaultUserAgent builds and returns the default user agent string.
 func defaultUserAgent() string {
-	return fmt.Sprintf("oxide.go/%s", version)
+	return fmt.Sprintf("oxide.go/%s", sdkVersion)
 }
 
 // getProfile determines the path of the user's credentials file
@@ -305,6 +305,7 @@ func (c *Client) buildRequest(ctx context.Context, body io.Reader, method, uri s
 
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", c.token))
+	req.Header.Set("API-Version", openAPIVersion)
 
 	// Add the parameters to the url.
 	if err := expandURL(req.URL, params); err != nil {