refactor(helm): jsonnet.go

Moves Jsonnet native func related code into jsonnet.go

pkg/helm/helm.go

@@ -7,7 +7,6 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
-	"strings"
 
 	"github.com/grafana/tanka/pkg/kubernetes/manifest"
 )
@@ -24,40 +23,6 @@ type Helm interface {
 	Template(name, chart string, opts TemplateOpts) (manifest.List, error)
 }
 
-type TemplateOpts struct {
-	// Values to pass to Helm using --values
-	Values map[string]interface{}
-
-	// Kubernetes api versions used for Capabilities.APIVersions
-	APIVersions []string
-	// IncludeCRDs specifies whether CustomResourceDefinitions are included in
-	// the template output
-	IncludeCRDs bool
-	// Namespace scope for this request
-	Namespace string
-}
-
-// Flags returns all options apart from Values as their respective `helm
-// template` flag equivalent
-func (t TemplateOpts) Flags() []string {
-	var flags []string
-
-	if t.APIVersions != nil {
-		value := strings.Join(t.APIVersions, ",")
-		flags = append(flags, "--api-versions="+value)
-	}
-
-	if t.IncludeCRDs {
-		flags = append(flags, "--include-crds")
-	}
-
-	if t.Namespace != "" {
-		flags = append(flags, "--namespace="+t.Namespace)
-	}
-
-	return flags
-}
-
 // PullOpts are additional, non-required options for Helm.Pull
 type PullOpts struct {
 	Opts

pkg/helm/jsonnet.go

@@ -0,0 +1,143 @@
+package helm
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"text/template"
+
+	"github.com/Masterminds/sprig/v3"
+	"github.com/google/go-jsonnet"
+	"github.com/google/go-jsonnet/ast"
+	"github.com/grafana/tanka/pkg/kubernetes/manifest"
+)
+
+// DefaultNameFormat to use when no nameFormat is supplied
+const DefaultNameFormat = `{{ print .kind "_" .metadata.name | snakecase }}`
+
+// JsonnetOpts are additional properties the consumer of the native func might
+// pass.
+type JsonnetOpts struct {
+	TemplateOpts
+
+	// CalledFrom is the file that calls helmTemplate. This is used to find the
+	// vendored chart relative to this file
+	CalledFrom string `json:"calledFrom"`
+	// NameTemplate is used to create the keys in the resulting map
+	NameFormat string `json:"nameFormat"`
+}
+
+// NativeFunc returns a jsonnet native function that provides the same
+// functionality as `Helm.Template` of this package. Charts are required to be
+// present on the local filesystem, at a relative location to the file that
+// calls `helm.template()` / `std.native('helmTemplate')`. This guarantees
+// hermeticity
+func NativeFunc(h Helm) *jsonnet.NativeFunction {
+	return &jsonnet.NativeFunction{
+		Name: "helmTemplate",
+		// Similar to `helm template [NAME] [CHART] [flags]` except 'conf' is a
+		// bit more elaborate and chart is a local path
+		Params: ast.Identifiers{"name", "chart", "opts"},
+		Func: func(data []interface{}) (interface{}, error) {
+			name, ok := data[0].(string)
+			if !ok {
+				return nil, fmt.Errorf("First argument 'name' must be of 'string' type, got '%T' instead", data[0])
+			}
+
+			chartpath, ok := data[1].(string)
+			if !ok {
+				return nil, fmt.Errorf("Second argument 'chart' must be of 'string' type, got '%T' instead", data[1])
+			}
+
+			// TODO: validate data[2] actually follows the struct scheme
+			opts, err := parseOpts(data[2])
+			if err != nil {
+				return "", err
+			}
+
+			// resolve the Chart relative to the caller
+			callerDir := filepath.Dir(opts.CalledFrom)
+			chart := filepath.Join(callerDir, chartpath)
+			if _, err := os.Stat(chart); err != nil {
+				// TODO: add website link for explanation
+				return nil, fmt.Errorf("helmTemplate: Failed to find a Chart at '%s': %s", chart, err)
+			}
+
+			// render resources
+			list, err := h.Template(name, chart, opts.TemplateOpts)
+			if err != nil {
+				return nil, err
+			}
+
+			// convert list to map
+			out, err := listAsMap(list, opts.NameFormat)
+			if err != nil {
+				return nil, err
+			}
+
+			return out, nil
+		},
+	}
+}
+
+func parseOpts(data interface{}) (*JsonnetOpts, error) {
+	c, err := json.Marshal(data)
+	if err != nil {
+		return nil, err
+	}
+	var opts JsonnetOpts
+	if err := json.Unmarshal(c, &opts); err != nil {
+		return nil, err
+	}
+
+	// Charts are only allowed at relative paths. Use conf.CalledFrom to find the callers directory
+	if opts.CalledFrom == "" {
+		// TODO: rephrase and move lengthy explanation to website
+		return nil, fmt.Errorf("helmTemplate: 'opts.calledFrom' is unset or empty.\nTanka must know where helmTemplate was called from to resolve the Helm Chart relative to that.\n")
+	}
+
+	return &opts, nil
+}
+
+func listAsMap(list manifest.List, nameFormat string) (map[string]interface{}, error) {
+	if nameFormat == "" {
+		nameFormat = DefaultNameFormat
+	}
+
+	tmpl, err := template.New("").
+		Funcs(sprig.TxtFuncMap()).
+		Parse(nameFormat)
+	if err != nil {
+		return nil, fmt.Errorf("Parsing name format: %w", err)
+	}
+
+	out := make(map[string]interface{})
+	for _, m := range list {
+		var buf bytes.Buffer
+		if err := tmpl.Execute(&buf, m); err != nil {
+			return nil, err
+		}
+		name := buf.String()
+
+		if _, ok := out[name]; ok {
+			return nil, ErrorDuplicateName{name: name, format: nameFormat}
+		}
+		out[name] = map[string]interface{}(m)
+	}
+
+	return out, nil
+}
+
+// ErrorDuplicateName means two resources share the same name using the given
+// nameFormat.
+type ErrorDuplicateName struct {
+	name   string
+	format string
+}
+
+func (e ErrorDuplicateName) Error() string {
+	// TODO: explain on website
+	return fmt.Sprintf("Two resources share the same name '%s'. Please adapt the name template '%s'", e.name, e.format)
+}

pkg/helm/template.go

@@ -2,36 +2,15 @@ package helm
 
 import (
 	"bytes"
-	"encoding/json"
-	"fmt"
 	"io"
 	"os"
-	"path/filepath"
-	"text/template"
+	"strings"
 
-	"github.com/Masterminds/sprig/v3"
-	jsonnet "github.com/google/go-jsonnet"
-	"github.com/google/go-jsonnet/ast"
 	"github.com/grafana/tanka/pkg/kubernetes/manifest"
 	"github.com/pkg/errors"
 	yaml "gopkg.in/yaml.v3"
 )
 
-// DefaultNameFormat to use when no nameFormat is supplied
-const DefaultNameFormat = `{{ print .kind "_" .metadata.name | snakecase }}`
-
-// JsonnetOpts are additional properties the consumer of the native func might
-// pass.
-type JsonnetOpts struct {
-	TemplateOpts
-
-	// CalledFrom is the file that calls helmTemplate. This is used to find the
-	// vendored chart relative to this file
-	CalledFrom string `json:"calledFrom"`
-	// NameTemplate is used to create the keys in the resulting map
-	NameFormat string `json:"nameFormat"`
-}
-
 // Template expands a Helm Chart into a regular manifest.List using the `helm
 // template` command
 func (h ExecHelm) Template(name, chart string, opts TemplateOpts) (manifest.List, error) {
@@ -78,104 +57,37 @@ func (h ExecHelm) Template(name, chart string, opts TemplateOpts) (manifest.List
 	return list, nil
 }
 
-// NativeFunc returns a jsonnet native function that provides the same
-// functionality as `Helm.Template` of this package. Charts are required to be
-// present on the local filesystem, at a relative location to the file that
-// calls `helm.template()` / `std.native('helmTemplate')`. This guarantees
-// hermeticity
-func NativeFunc(h Helm) *jsonnet.NativeFunction {
-	return &jsonnet.NativeFunction{
-		Name: "helmTemplate",
-		// Similar to `helm template [NAME] [CHART] [flags]` except 'conf' is a
-		// bit more elaborate and chart is a local path
-		Params: ast.Identifiers{"name", "chart", "opts"},
-		Func: func(data []interface{}) (interface{}, error) {
-			name, ok := data[0].(string)
-			if !ok {
-				return nil, fmt.Errorf("First argument 'name' must be of 'string' type, got '%T' instead", data[0])
-			}
-
-			chartpath, ok := data[1].(string)
-			if !ok {
-				return nil, fmt.Errorf("Second argument 'chart' must be of 'string' type, got '%T' instead", data[1])
-			}
-
-			// TODO: validate data[2] actually follows the struct scheme
-			opts, err := parseOpts(data[2])
-			if err != nil {
-				return "", err
-			}
-
-			// resolve the Chart relative to the caller
-			callerDir := filepath.Dir(opts.CalledFrom)
-			chart := filepath.Join(callerDir, chartpath)
-			if _, err := os.Stat(chart); err != nil {
-				// TODO: add website link for explanation
-				return nil, fmt.Errorf("helmTemplate: Failed to find a Chart at '%s': %s", chart, err)
-			}
-
-			// render resources
-			list, err := h.Template(name, chart, opts.TemplateOpts)
-			if err != nil {
-				return nil, err
-			}
-
-			// convert list to map
-			out, err := listAsMap(list, opts.NameFormat)
-			if err != nil {
-				return nil, err
-			}
-
-			return out, nil
-		},
-	}
+// TemplateOpts are additional, non-required options for Helm.Template
+type TemplateOpts struct {
+	// Values to pass to Helm using --values
+	Values map[string]interface{}
+
+	// Kubernetes api versions used for Capabilities.APIVersions
+	APIVersions []string
+	// IncludeCRDs specifies whether CustomResourceDefinitions are included in
+	// the template output
+	IncludeCRDs bool
+	// Namespace scope for this request
+	Namespace string
 }
 
-func parseOpts(data interface{}) (*JsonnetOpts, error) {
-	c, err := json.Marshal(data)
-	if err != nil {
-		return nil, err
-	}
-	var opts JsonnetOpts
-	if err := json.Unmarshal(c, &opts); err != nil {
-		return nil, err
-	}
-
-	// Charts are only allowed at relative paths. Use conf.CalledFrom to find the callers directory
-	if opts.CalledFrom == "" {
-		// TODO: rephrase and move lengthy explanation to website
-		return nil, fmt.Errorf("helmTemplate: 'opts.calledFrom' is unset or empty.\nTanka must know where helmTemplate was called from to resolve the Helm Chart relative to that.\n")
-	}
+// Flags returns all options apart from Values as their respective `helm
+// template` flag equivalent
+func (t TemplateOpts) Flags() []string {
+	var flags []string
 
-	if opts.NameFormat == "" {
-		opts.NameFormat = DefaultNameFormat
+	if t.APIVersions != nil {
+		value := strings.Join(t.APIVersions, ",")
+		flags = append(flags, "--api-versions="+value)
 	}
 
-	return &opts, nil
-}
-
-func listAsMap(list manifest.List, nameFormat string) (map[string]interface{}, error) {
-	tmpl, err := template.New("").
-		Funcs(sprig.TxtFuncMap()).
-		Parse(nameFormat)
-	if err != nil {
-		return nil, fmt.Errorf("Parsing name format: %w", err)
+	if t.IncludeCRDs {
+		flags = append(flags, "--include-crds")
 	}
 
-	out := make(map[string]interface{})
-	for _, m := range list {
-		var buf bytes.Buffer
-		if err := tmpl.Execute(&buf, m); err != nil {
-			return nil, err
-		}
-		name := buf.String()
-
-		if _, ok := out[name]; ok {
-			// TODO: explain on website
-			return nil, fmt.Errorf("Two resources share the same name '%s'. Please adapt the name template '%s'", name, nameFormat)
-		}
-		out[name] = map[string]interface{}(m)
+	if t.Namespace != "" {
+		flags = append(flags, "--namespace="+t.Namespace)
 	}
 
-	return out, nil
+	return flags
 }