conf: add pretty printing,raw conf, conf tests

* also, set debug logger directly in config if devel mode is set
* add new flag to indicate whether the passed config is path or raw
  config

config/config.go

@@ -1,6 +1,12 @@
 package config
 
 import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"time"
+
 	"git.dotya.ml/mirre-mt/pcmt/slogging"
 	"github.com/philandstuff/dhall-golang/v6"
 )
@@ -15,15 +21,72 @@ type Config struct {
 	SessionCookieSecret string
 }
 
-func LoadConfig(path string) (*Config, error) {
+func LoadConfig(conf string, isPath bool) (*Config, error) {
 	var config Config
 
-	err := dhall.UnmarshalFile(path, &config)
+	var err error
+
+	if isPath {
+		slogging.GetLogger().Debug("config from file")
+
+		err = dhall.UnmarshalFile(conf, &config)
+	} else {
+		slogging.GetLogger().Debug("config raw from cmdline")
+
+		err = dhall.Unmarshal([]byte(conf), &config)
+	}
+
 	if err != nil {
 		return nil, err
 	}
 
-	slogging.GetLogger().Debugf("parsed config: %+v", config)
+	if config.DevelMode {
+		_ = slogging.SetLevel(slogging.LevelDebug)
+
+		slogging.GetLogger().Debugf("parsed config: %+v", config)
+
+		if dhallCmdExists() {
+			_ = prettyPrintConfig(conf, isPath)
+		}
+	}
 
 	return &config, nil
 }
+
+func prettyPrintConfig(conf string, isPath bool) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+
+	var cmd *exec.Cmd
+	if isPath {
+		cmd = exec.CommandContext(ctx, "/bin/sh", "-c", "dhall --file "+conf) //nolint:gosec
+	} else {
+		cmd = exec.CommandContext(ctx, "/bin/sh", "-c", "dhall <<< \""+conf+"\"") //nolint:gosec
+	}
+
+	output, err := cmd.CombinedOutput()
+	if err != nil {
+		slogging.GetLogger().Debug("could not pretty-print config", "error", err)
+		return err
+	}
+
+	if isPath {
+		fmt.Fprintln(os.Stderr, "\n"+conf+":\n"+string(output))
+	} else {
+		fmt.Fprintln(os.Stderr, "\nconfig:\n"+string(output))
+	}
+
+	return nil
+}
+
+func dhallCmdExists() bool {
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+
+	if err := exec.CommandContext(ctx, "/bin/sh", "-c", "command -v dhall").Run(); err != nil {
+		slogging.GetLogger().Debug("no command dhall")
+		return false
+	}
+
+	return true
+}

config/config_test.go

@@ -0,0 +1,114 @@
+package config
+
+import (
+	"os"
+	"testing"
+
+	"git.dotya.ml/mirre-mt/pcmt/slogging"
+)
+
+func TestConfig(t *testing.T) {
+	if os.Getenv("CI") == "true" {
+		t.Skip("we're running in CI apparently, skipping these tests")
+	}
+
+	confPath := "./testconfigs/"
+	ts := []struct {
+		name   string
+		fails  bool
+		isPath bool
+		conf   string
+	}{
+		{
+			// incorrect type of the `Host` field.
+			name:   "1.dhall",
+			fails:  true,
+			isPath: true,
+			conf:   "1.dhall",
+		},
+		{
+			name:   "2.dhall",
+			fails:  false,
+			isPath: true,
+			conf:   "2.dhall",
+		},
+		{
+			name:   "3.dhall",
+			fails:  false,
+			isPath: false,
+			conf: `
+			let ConfigSchema =
+				  https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+					sha256:ad7ba86d5d388a99b7543faa0e4c81ba1d9b78fa6c32fdaf4ac4477089d177be
+				  ? https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+
+			let Config = ConfigSchema.Schema
+
+			let c = Config::{ DevelMode = True }
+
+			in  c
+			`,
+		},
+		{
+			// misses final `in`.
+			name:   "4.dhall",
+			fails:  true,
+			isPath: false,
+			conf: `
+			let ConfigSchema =
+				  https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+					sha256:ad7ba86d5d388a99b7543faa0e4c81ba1d9b78fa6c32fdaf4ac4477089d177be
+				  ? https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+
+			let Config = ConfigSchema.Schema
+
+			let c = Config::{ DevelMode = True }
+			`,
+		},
+		{
+			name:   "5.dhall",
+			fails:  false,
+			isPath: false,
+			conf: `
+			let ConfigSchema =
+				  https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+			in ConfigSchema.Schema::{ DevelMode = True, Port = 5555 }
+			`,
+		},
+		{
+			name:   "6.dhall",
+			fails:  false,
+			isPath: false,
+			conf: `
+			let ConfigSchema =
+				  https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+			in ConfigSchema.Schema.default // { DevelMode = True }
+			`,
+		},
+	}
+
+	_ = slogging.Init(false)
+
+	for _, tc := range ts {
+		t.Logf("running test case %s", tc.name)
+
+		var err error
+
+		shouldFail := tc.fails
+
+		if tc.isPath {
+			_, err = LoadConfig(confPath+tc.conf, tc.isPath)
+		} else {
+			_, err = LoadConfig(tc.conf, tc.isPath)
+		}
+
+		switch {
+		case err == nil && shouldFail:
+			t.Errorf("test case '%s' should have failed", tc.name)
+
+		case err != nil && !shouldFail:
+			t.Log(err)
+			t.Errorf("test case '%s' should not have failed", tc.name)
+		}
+	}
+}

config/testconfigs/1.dhall

@@ -0,0 +1,9 @@
+let ConfigSchema =
+      https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+        sha256:ad7ba86d5d388a99b7543faa0e4c81ba1d9b78fa6c32fdaf4ac4477089d177be
+
+let Config = ConfigSchema.Schema
+
+let c = Config::{ Host = False }
+
+in  c

config/testconfigs/2.dhall

@@ -0,0 +1,9 @@
+let ConfigSchema =
+      https://git.dotya.ml/mirre-mt/pcmt/raw/branch/development/config/schema/package.dhall
+        sha256:ad7ba86d5d388a99b7543faa0e4c81ba1d9b78fa6c32fdaf4ac4477089d177be
+
+let Config = ConfigSchema.Schema
+
+let c = Config::{ Host = "localhost" }
+
+in  c

run.go

@@ -51,13 +51,14 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.`
 )
 
 var (
-	host       = flag.String("host", "unset", "host address to listen on")
-	port       = flag.Int("port", -1, "TCP port to listen on")
-	configFlag = flag.String("config", "config.dhall", "Default path of the config file")
-	devel      = flag.Bool("devel", false, "Run the application in dev mode, connect to a local browser-sync instance for hot-reloading")
-	license    = flag.Bool("license", false, "Print licensing information and exit")
-	version    = "dev"
-	log        *slogging.Logger
+	host             = flag.String("host", "unset", "host address to listen on")
+	port             = flag.Int("port", -1, "TCP port to listen on")
+	configFlag       = flag.String("config", "config.dhall", "Default path of the config file")
+	configIsPathFlag = flag.Bool("configIsPath", true, "Whether the provided config is path or raw config")
+	devel            = flag.Bool("devel", false, "Run the application in dev mode, connect to a local browser-sync instance for hot-reloading")
+	license          = flag.Bool("license", false, "Print licensing information and exit")
+	version          = "dev"
+	log              *slogging.Logger
 )
 
 func run() error {
@@ -81,9 +82,9 @@ func run() error {
 	// TODO: SBOM: https://actuated.dev/blog/sbom-in-github-actions
 	// TODO: SBOM: https://www.docker.com/blog/generate-sboms-with-buildkit/
 
-	conf, err := config.LoadConfig(*configFlag)
+	conf, err := config.LoadConfig(*configFlag, *configIsPathFlag)
 	if err != nil {
-		log.Errorf("error loading config file at '%s', bailing", *configFlag)
+		log.Errorf("error loading config file '%s', bailing", *configFlag)
 		return err
 	}