refactor: api (#97)

Refactors all of the actual application logic out of the main package, into the `github.com/grafana/tanka/pkg/tanka` package, which effectively forms an API for Tanka, allowing it to be imported into other projects and used from there.

The API is loosely based on the CLI, ie it follows the same scheme:

    tanka.Apply("environments/default")

To change the behaviour of these calls, for example the diff strategy, modifiers can be used (https://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis):

    tanka.Apply("environments/default", tanka.WithApplyForce(true))

Does some further cleanup on the whole repository, ie implementing linter suggestions and moving the `main` package from the former global based approach to the new package, which should resolve `nil` receiver panics for workflow operations forever.

cmd/tk/env.go

@@ -8,12 +8,13 @@ import (
 	"path/filepath"
 	"text/tabwriter"
 
+	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
 
+	"github.com/grafana/tanka/pkg/cli"
 	"github.com/grafana/tanka/pkg/spec/v1alpha1"
-	"github.com/grafana/tanka/pkg/util"
 )
 
 func envCmd() *cobra.Command {
@@ -50,7 +51,7 @@ func envSetCmd() *cobra.Command {
 	envSettingsFlags(&tmp, cmd.Flags())
 
 	name := cmd.Flags().String("name", "", "")
-	cmd.Flags().MarkHidden("name")
+	_ = cmd.Flags().MarkHidden("name")
 
 	cmd.Run = func(cmd *cobra.Command, args []string) {
 		if *name != "" {
@@ -115,14 +116,16 @@ func addEnv(dir string, cfg *v1alpha1.Config) error {
 	if _, err := os.Stat(path); err != nil {
 		// folder does not exist
 		if os.IsNotExist(err) {
-			os.MkdirAll(path, os.ModePerm)
+			if err := os.MkdirAll(path, os.ModePerm); err != nil {
+				return errors.Wrap(err, "creating directory")
+			}
 		} else {
 			// it exists
 			if os.IsExist(err) {
-				return fmt.Errorf("Directory %s already exists.", path)
+				return fmt.Errorf("directory %s already exists", path)
 			}
 			// we have another error
-			return fmt.Errorf("Creating directory: %s", err)
+			return errors.Wrap(err, "creating directory")
 		}
 	}
 
@@ -156,7 +159,7 @@ func envRemoveCmd() *cobra.Command {
 				if err != nil {
 					log.Fatalln("parsing environments name:", err)
 				}
-				if err := util.Confirm(fmt.Sprintf("Permanently removing the environment located at '%s'.", path), "yes"); err != nil {
+				if err := cli.Confirm(fmt.Sprintf("Permanently removing the environment located at '%s'.", path), "yes"); err != nil {
 					log.Fatalln(err)
 				}
 				if err := os.RemoveAll(path); err != nil {
@@ -179,7 +182,7 @@ func envListCmd() *cobra.Command {
 	cmd.Run = func(cmd *cobra.Command, args []string) {
 		envs := []v1alpha1.Config{}
 		dirs := findBaseDirs()
-		useJson, err := cmd.Flags().GetBool("json")
+		useJSON, err := cmd.Flags().GetBool("json")
 		if err != nil {
 			// this err should never occur. Panic in case
 			panic(err)
@@ -189,7 +192,7 @@ func envListCmd() *cobra.Command {
 			envs = append(envs, *setupConfiguration(dir))
 		}
 
-		if useJson {
+		if useJSON {
 			j, err := json.Marshal(envs)
 			if err != nil {
 				log.Fatalln("Formatting as json:", j)

cmd/tk/init.go

@@ -45,7 +45,6 @@ func initCmd() *cobra.Command {
 		}
 
 		fmt.Println("Directory structure set up! Remember to configure the API endpoint:\n`tk env set environments/default --server=127.0.0.1:6443`")
-
 	}
 	return cmd
 }

cmd/tk/jsonnet.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"encoding/json"
 	"log"
 	"path/filepath"
 
@@ -47,16 +46,3 @@ func eval(workdir string) (string, error) {
 	}
 	return json, nil
 }
-
-func evalDict(workdir string) (map[string]interface{}, error) {
-	var rawDict map[string]interface{}
-
-	raw, err := eval(workdir)
-	if err != nil {
-		return nil, err
-	}
-	if err := json.Unmarshal([]byte(raw), &rawDict); err != nil {
-		return nil, err
-	}
-	return rawDict, nil
-}

cmd/tk/main.go

@@ -11,8 +11,7 @@ import (
 	"github.com/spf13/viper"
 	"golang.org/x/crypto/ssh/terminal"
 
-	"github.com/grafana/tanka/pkg/cmp"
-	"github.com/grafana/tanka/pkg/kubernetes"
+	"github.com/grafana/tanka/pkg/cli/cmp"
 	"github.com/grafana/tanka/pkg/spec"
 	"github.com/grafana/tanka/pkg/spec/v1alpha1"
 )
@@ -21,47 +20,19 @@ import (
 // To be overwritten at build time
 var Version = "dev"
 
-// primary handlers
-var (
-	config = &v1alpha1.Config{}
-	kube   *kubernetes.Kubernetes
-)
-
 // describing variables
 var (
 	verbose     = false
 	interactive = terminal.IsTerminal(int(os.Stdout.Fd()))
 )
 
-// list of deprecated config keys and their alternatives
-// however, they still work and are aliased internally
-var deprecated = map[string]string{
-	"namespace": "spec.namespace",
-	"server":    "spec.apiServer",
-	"team":      "metadata.labels.team",
-}
-
 func main() {
 	log.SetFlags(0)
 	rootCmd := &cobra.Command{
 		Use:              "tk",
 		Short:            "tanka <3 jsonnet",
 		Version:          Version,
 		TraverseChildren: true,
-		// Configuration
-		PersistentPreRun: func(cmd *cobra.Command, args []string) {
-			if len(args) == 0 {
-				return
-			}
-			config = setupConfiguration(args[0])
-			if config == nil {
-				return
-			}
-
-			// Kubernetes
-			kube = kubernetes.New(config.Spec)
-
-		},
 	}
 	rootCmd.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false, "")
 

cmd/tk/util.go

@@ -57,11 +57,11 @@ func highlight(lang, s string) string {
 func writeJSON(i interface{}, path string) error {
 	out, err := json.MarshalIndent(i, "", "  ")
 	if err != nil {
-		return fmt.Errorf("Marshalling: %s", err)
+		return fmt.Errorf("marshalling: %s", err)
 	}
 
 	if err := ioutil.WriteFile(path, append(out, '\n'), 0644); err != nil {
-		return fmt.Errorf("Writing %s: %s", path, err)
+		return fmt.Errorf("writing %s: %s", path, err)
 	}
 
 	return nil

cmd/tk/workflow.go

@@ -11,8 +11,16 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 
-	"github.com/grafana/tanka/pkg/cmp"
-	"github.com/grafana/tanka/pkg/kubernetes"
+	"github.com/grafana/tanka/pkg/cli/cmp"
+	"github.com/grafana/tanka/pkg/tanka"
+)
+
+// special exit codes for tk diff
+const (
+	// no changes
+	ExitStatusClean = 0
+	// differences between the local config and the cluster
+	ExitStatusDiff = 16
 )
 
 type workflowFlagVars struct {
@@ -38,29 +46,13 @@ func applyCmd() *cobra.Command {
 	force := cmd.Flags().Bool("force", false, "force applying (kubectl apply --force)")
 	autoApprove := cmd.Flags().Bool("dangerous-auto-approve", false, "skip interactive approval. Only for automation!")
 	cmd.Run = func(cmd *cobra.Command, args []string) {
-		if kube == nil {
-			log.Fatalln(kubernetes.ErrorMissingConfig{Verb: "apply"})
-		}
-
-		raw, err := evalDict(args[0])
+		err := tanka.Apply(args[0],
+			tanka.WithTargets(stringsToRegexps(vars.targets)...),
+			tanka.WithApplyForce(*force),
+			tanka.WithApplyAutoApprove(*autoApprove),
+		)
 		if err != nil {
-			log.Fatalln("Evaluating jsonnet:", err)
-		}
-
-		desired, err := kube.Reconcile(raw, stringsToRegexps(vars.targets)...)
-		if err != nil {
-			log.Fatalln("Reconciling:", err)
-		}
-
-		if !diff(desired, false, kubernetes.DiffOpts{}) {
-			log.Println("Warning: There are no differences. Your apply may not do anything at all.")
-		}
-
-		if err := kube.Apply(desired, kubernetes.ApplyOpts{
-			Force:       *force,
-			AutoApprove: *autoApprove,
-		}); err != nil {
-			log.Fatalln("Applying:", err)
+			log.Fatalln(err)
 		}
 	}
 	return cmd
@@ -88,58 +80,31 @@ func diffCmd() *cobra.Command {
 	)
 
 	cmd.Run = func(cmd *cobra.Command, args []string) {
-		if kube == nil {
-			log.Fatalln(kubernetes.ErrorMissingConfig{Verb: "diff"})
-		}
-
-		raw, err := evalDict(args[0])
-		if err != nil {
-			log.Fatalln("Evaluating jsonnet:", err)
-		}
-
-		if kube.Spec.DiffStrategy == "" {
-			kube.Spec.DiffStrategy = *diffStrategy
-		}
-
-		desired, err := kube.Reconcile(raw, stringsToRegexps(vars.targets)...)
+		changes, err := tanka.Diff(args[0],
+			tanka.WithTargets(stringsToRegexps(vars.targets)...),
+			tanka.WithDiffStrategy(*diffStrategy),
+			tanka.WithDiffSummarize(*summarize),
+		)
 		if err != nil {
-			log.Fatalln("Reconciling:", err)
+			log.Fatalln(err)
 		}
 
-		if diff(desired, interactive, kubernetes.DiffOpts{Summarize: *summarize}) {
-			os.Exit(16)
+		if changes == nil {
+			log.Println("No differences.")
+			os.Exit(ExitStatusClean)
 		}
-		log.Println("No differences.")
-	}
-
-	return cmd
-}
-
-// computes the diff, prints to screen.
-// set `pager` to false to disable the pager.
-// When non-interactive, no paging happens anyways.
-func diff(state []kubernetes.Manifest, pager bool, opts kubernetes.DiffOpts) (changed bool) {
-	changes, err := kube.Diff(state, opts)
-	if err != nil {
-		log.Fatalln("Diffing:", err)
-	}
-
-	if changes == nil {
-		return false
-	}
 
-	if interactive {
-		h := highlight("diff", *changes)
-		if pager {
+		if interactive {
+			h := highlight("diff", *changes)
 			pageln(h)
 		} else {
-			fmt.Println(h)
+			fmt.Println(*changes)
 		}
-	} else {
-		fmt.Println(*changes)
+
+		os.Exit(ExitStatusDiff)
 	}
 
-	return true
+	return cmd
 }
 
 func showCmd() *cobra.Command {
@@ -152,26 +117,18 @@ func showCmd() *cobra.Command {
 		},
 	}
 	vars := workflowFlags(cmd.Flags())
-	canRedirect := cmd.Flags().Bool("dangerous-allow-redirect", false, "allow redirecting output to a file or a pipe.")
+	allowRedirect := cmd.Flags().Bool("dangerous-allow-redirect", false, "allow redirecting output to a file or a pipe.")
 	cmd.Run = func(cmd *cobra.Command, args []string) {
-		if !interactive && !*canRedirect {
+		if !interactive && !*allowRedirect {
 			fmt.Fprintln(os.Stderr, "Redirection of the output of tk show is discouraged and disabled by default. Run tk show --dangerous-allow-redirect to enable.")
 			return
 		}
 
-		raw, err := evalDict(args[0])
-		if err != nil {
-			log.Fatalln("Evaluating jsonnet:", err)
-		}
-
-		state, err := kube.Reconcile(raw, stringsToRegexps(vars.targets)...)
-		if err != nil {
-			log.Fatalln("Reconciling:", err)
-		}
-
-		pretty, err := kube.Fmt(state)
+		pretty, err := tanka.Show(args[0],
+			tanka.WithTargets(stringsToRegexps(vars.targets)...),
+		)
 		if err != nil {
-			log.Fatalln("Pretty printing state:", err)
+			log.Fatalln(err)
 		}
 
 		pageln(pretty)

go.mod

@@ -20,4 +20,5 @@ require (
 	golang.org/x/sys v0.0.0-20190616124812-15dcb6c0061f // indirect
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/yaml.v2 v2.2.2
+	gopkg.in/yaml.v3 v3.0.0-20191010095647-fc94e3f71652
 )

go.sum

@@ -124,3 +124,5 @@ gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20191010095647-fc94e3f71652 h1:VKvJ/mQ4BgCjZUDggYFxTe0qv9jPMHsZPD4Xt91Y5H4=
+gopkg.in/yaml.v3 v3.0.0-20191010095647-fc94e3f71652/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

pkg/util/alert.go → pkg/cli/alert.go

@@ -1,4 +1,4 @@
-package util
+package cli
 
 import (
 	"bufio"

pkg/jsonnet/imports.go

@@ -39,7 +39,7 @@ func TransitiveImports(filename string) ([]string, error) {
 		return nil, errors.Wrap(err, "creating Jsonnet AST")
 	}
 
-	imports := make([]string, 0, 0)
+	imports := make([]string, 0)
 	err = importRecursive(&imports, vm, node, "main.jsonnet")
 
 	return uniqueStringSlice(imports), err

pkg/kubernetes/errors.go

@@ -1,6 +1,9 @@
 package kubernetes
 
-import "fmt"
+import (
+	"errors"
+	"fmt"
+)
 
 type ErrorNotFound struct {
 	name string
@@ -11,10 +14,6 @@ func (e ErrorNotFound) Error() string {
 	return fmt.Sprintf(`error from server (NotFound): %s "%s" not found`, e.kind, e.name)
 }
 
-type ErrorMissingConfig struct {
-	Verb string
-}
-
-func (e ErrorMissingConfig) Error() string {
-	return fmt.Sprintf("%s requires additional configuration. Refer to https://tanka.dev/environments for that.", e.Verb)
-}
+var (
+	ErrorMissingConfig = errors.New("This operation requires additional configuration. Refer to https://tanka.dev/environments for instructions")
+)