Add gomod-sync tool (#1954)

.github/workflows/gomod-sync.yml

@@ -0,0 +1,26 @@
+name: go.mod check
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  check:
+    name: go.mod check
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions/setup-go@v2
+        with:
+          go-version: 1.17
+
+      - name: Check go.mod files
+        shell: bash
+        run: |
+          cd gomod-sync
+          go run main.go check

.gitignore

@@ -6,3 +6,9 @@ bin/configlet
 bin/configlet.exe
 bin/golangci-lint
 bin/golangci-lint.exe
+
+# gomod-sync
+
+gomod-sync/gomod-sync
+gomod-sync/gomod-sync.exe
+gomod-sync/vendor

README.md

@@ -225,6 +225,23 @@ To regenerate the test cases, navigate into the **go** directory and run
 `GO111MODULE=off go run exercises/practice/<exercise>/.meta/gen.go`. You should see that the
 `<exercise>/cases_test.go` file has changed. Commit the change.
 
+## Managing the Go version
+
+For an easy managment of the Go version in the `go.mod` file in all exercises, we can use `gomod-sync`.
+This is a tool made in Go that can be seen in the `gomod-sync/` folder.
+
+To update all go.mod files according to the config file (`gomod-sync/config.json`) run:
+
+```console
+$ cd gomod-sync && go run main.go update
+```
+
+To check all exercise go.mod files specify the correct Go version, run:
+
+```console
+$ cd gomod-sync && go run main.go check
+```
+
 ## Pull requests
 
 Pull requests are welcome.

gomod-sync/README.md

@@ -0,0 +1,152 @@
+# gomod-sync
+
+Utility tool to check and update the Go version specified in the `go.mod` files of all exercises.
+It works by specifying the desired Go version for all the `go.mod` files to be in. The `check` command
+will verify if all `go.mod` files are in the desired version and the `update` command will update all
+`go.mod` files to have the desired Go version.
+
+Some exercises must have its `go.mod` specify a Go version that is different from the other exercise's `go.mod`.
+This is supported by the `exceptions` key of the configuration file, where an entry must exist for each exercise
+that must not have the default version.
+
+## Quick start
+
+To update all go.mod files according to the config file (gomod-sync/config.json) run:
+
+```console
+$ cd gomod-sync
+$ go run main.go update
+```
+
+To check all exercise go.mod files specify the correct Go version, run:
+
+```console
+$ cd gomod-sync
+$ go run main.go check
+```
+
+## Installing
+
+### Compiling locally
+
+```console
+$ cd gomod-sync
+$ go build
+```
+
+This will create an executable `gomod-sync` (`gomod-sync.exe` in windows) in the current directory 
+that you can run to execute the program.
+
+### Running without compiling
+
+```console
+$ cd gomod-sync
+$ go run main.go <command> [flags]
+```
+
+### Running the tests
+
+```console
+$ cd gomod-sync
+$ go test ./...
+```
+
+## Usage
+
+```
+  gomod-sync commandUpdate gitig [flags]
+
+Available Commands:
+  check       Checks if all go.mod files are in the target version
+  update      Updates go.mod files to the target version
+  help        Help about any command
+
+```
+
+## Commands
+
+- `gomod-sync check -v target_version [-e exercises_path] [-c config_file]`
+
+  checks if all `go.mod` files are in the target version
+
+- `gomod-sync completion`
+
+  generate the autocompletion script for the specified shell
+- `gomod-sync help`
+
+  Help about any command
+- `gomod-sync list [-e exercises_path]`
+
+  list `go.mod` files and the Go version they specify
+- `gomod-sync update -v target_version [-e exercises_path] [-c config_file]`
+
+  updates `go.mod` files to the target version
+
+## Flags
+
+- `-c, --config config_file`
+
+  path to the JSON configuration file.  (default `"config.json"`)
+
+- `-e, --exercises exercises_path`
+
+  path to the exercises folder. `go.mod` files will be recursively searched inside this directory. (default `"../exercises"`)
+- `-v, --goversion target_version`
+
+  target go version that all go.mod files are expected to have. 
+  This will be used to check if the `go.mod` files are in the expected version in case of the check command, 
+  and to update all `go.mod` files to this version in the case of the update command.
+  Using this flag will override the version specified in the config file.
+
+- `-h, --help`
+
+  help for gomod-sync
+
+
+## Configuration file
+
+Besides the `-v, --goversion` flag, it is also possible to specify the expected go versions for the `go.mod` files in a JSON configuration file.
+This file can be given to the program with the `-c, --config file` flag. If the flag is omitted, a file `config.json`
+in the current directory will be tried.
+
+With a configuration file, in addition to define a default Go version all exercises' `go.mod` must have, 
+it's also possible to configure different versions for different exercises. This can be useful if a particular exercise 
+needs a superior version of Go than the default.
+
+This an example of such configuration file:
+
+```json
+{
+  "default": "1.16",
+  "exceptions": [
+    {
+      "exercise": "strain",
+      "version": "1.18"
+    }
+  ]
+}
+```
+
+With such configuration, all `go.mod` files will be expected to have the `1.16` version of Go,
+except the exercise `strain`, which must have version `1.18` in its `go.mod`.
+Specifying the `-v, --goversion` flag overrides the default version specified in this file.
+
+## Examples
+
+
+* Check if all `go.mod` files of exercises in the `../exercises` folder have the default version 
+  specified in the `config.json` file:
+
+  * `gomod-sync check`
+
+* Check if all `go.mod` files of exercises in the `exercises` folder have the `1.16` Go version:
+
+  * `gomod-sync check --goversion 1.16 --exercises ./exercises`
+
+* Update all `go.mod` files of exercises in the `exercises` folder have the `1.16` Go version:
+
+  * `gomod-sync update --goversion 1.16 --exercises ./exercises`
+
+* Update all `go.mod` files, using a config file to specify the versions of exercises:
+
+  * `gomod-sync update --config a_dir/config.json --exercises ./exercises`

gomod-sync/cmd/check.go

@@ -0,0 +1,52 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/exercism/go/gomod-sync/gomod"
+	"github.com/logrusorgru/aurora/v3"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(checkCmd)
+}
+
+var checkCmd = &cobra.Command{
+	SilenceErrors:     true,
+	Use:               "check",
+	Short:             "Checks if all go.mod files are in the target version",
+	PersistentPreRunE: loadConfig,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		files, err := gomod.Infos(exercisesPathFlag)
+		if err != nil {
+			return err
+		}
+
+		type faultyFile struct {
+			gomod.Info
+			ExpectedVersion string
+		}
+
+		var faultyFiles []faultyFile
+		for _, file := range files {
+			expectedVersion := versionConfig.ExerciseExpectedVersion(file.ExerciseSlug)
+			if file.GoVersion != expectedVersion {
+				fmt.Println(aurora.Red(fmt.Sprintf("%v has version %s, but %s expected - FAIL", file.Path, file.GoVersion, expectedVersion)))
+				faultyFiles = append(faultyFiles, faultyFile{Info: file, ExpectedVersion: expectedVersion})
+			} else {
+				fmt.Println(aurora.Green(fmt.Sprintf("%v has version %s as expected - OK", file.Path, file.GoVersion)))
+			}
+		}
+
+		if len(faultyFiles) > 0 {
+			fmt.Println(aurora.Red(fmt.Sprintf("The following %d go.mod file(s) do not have the correct version set:", len(faultyFiles))))
+			for _, file := range faultyFiles {
+				fmt.Println(aurora.Red(fmt.Sprintf("\t%v has version %s, but %s expected", file.Path, file.GoVersion, file.ExpectedVersion)))
+			}
+			return fmt.Errorf("%d go.mod file(s) are not in the target version", len(faultyFiles))
+		}
+
+		return nil
+	},
+}

gomod-sync/cmd/config/load.go

@@ -0,0 +1,25 @@
+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+)
+
+// Load loads a configuration from a path to a JSON file.
+func Load(file string) (VersionConfig, error) {
+	var config VersionConfig
+
+	f, err := os.Open(file)
+	if err != nil {
+		return config, fmt.Errorf("failed to open config file: %v", err)
+	}
+	defer f.Close()
+
+	err = json.NewDecoder(f).Decode(&config)
+	if err != nil {
+		return config, fmt.Errorf("failed to decode config file: %v", err)
+	}
+
+	return config, nil
+}

gomod-sync/cmd/config/load_test.go

@@ -0,0 +1,103 @@
+package config_test
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/exercism/go/gomod-sync/cmd/config"
+)
+
+func TestLoad(t *testing.T) {
+	tests := []struct {
+		Name        string
+		Path        string
+		Expected    config.VersionConfig
+		ExpectError bool
+	}{
+		{
+			Name:        "Loading non-existent config",
+			Path:        filepath.Join("..", "..", "testdata", "non_existent.json"),
+			Expected:    config.VersionConfig{},
+			ExpectError: true,
+		},
+		{
+			Name: "Loading config with no exceptions",
+			Path: filepath.Join("..", "..", "testdata", "version_config_no_exceptions.json"),
+			Expected: config.VersionConfig{
+				Default: "1.16",
+			},
+			ExpectError: false,
+		},
+		{
+			Name: "Loading config with 1 exception",
+			Path: filepath.Join("..", "..", "testdata", "version_config_one_exception.json"),
+			Expected: config.VersionConfig{
+				Default: "1.16",
+				Exceptions: []config.ExerciseVersion{
+					{
+						Exercise: "exercise01",
+						Version:  "1.17",
+					},
+				},
+			},
+			ExpectError: false,
+		},
+		{
+			Name: "Loading config with 2 exceptions",
+			Path: filepath.Join("..", "..", "testdata", "version_config_two_exceptions.json"),
+			Expected: config.VersionConfig{
+				Default: "1.16",
+				Exceptions: []config.ExerciseVersion{
+					{
+						Exercise: "exercise01",
+						Version:  "1.17",
+					},
+					{
+						Exercise: "exercise02",
+						Version:  "1.17",
+					},
+				},
+			},
+			ExpectError: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.Name, func(t *testing.T) {
+			config, err := config.Load(test.Path)
+
+			if test.ExpectError && err == nil {
+				t.Fatalf("expected error, but got none")
+			}
+
+			if !test.ExpectError && err != nil {
+				t.Fatalf("didn't expect error, but got %v", err)
+			}
+
+			if !configEqual(config, test.Expected) {
+				t.Fatalf("expected config %+v, but got %+v", test.Expected, config)
+			}
+		})
+	}
+}
+
+func configEqual(a, b config.VersionConfig) bool {
+	return a.Default == b.Default && equalExceptions(a.Exceptions, b.Exceptions)
+}
+
+// equalExceptions compares two lists of exercise versions and tells if they are equal.
+// Two exercise list versions are considered equal if they contain the same elements
+// in the same order
+func equalExceptions(a, b []config.ExerciseVersion) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+
+	return true
+}