More detailed error handling when we fail to load JSON files

Closes #6
motns · May 14, 2020 · 12a6fc9 · 12a6fc9
1 parent 18a788c
commit 12a6fc9
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Showing 4 changed files with 44 additions and 8 deletions.
diff --git a/client/client.go b/client/client.go
@@ -28,7 +28,7 @@ func loadOverrides(paths []string) (map[string]string, error) {
 	for _, path := range paths {
 		m, err := loadOverride(path)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("%w; Failed to load override from file: %s", err, path)
 		}
 
 		for k, v := range m {
@@ -44,11 +44,16 @@ func loadOverride(path string) (map[string]string, error) {
 
 	jsonStr, err := ioutil.ReadFile(path)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("%w; Failed to read override file", err)
 	}
 
 	if err := json.Unmarshal(jsonStr, &overrides); err != nil {
-		return nil, err
+		switch t := err.(type) {
+		case *json.SyntaxError:
+			return nil, fmt.Errorf("%w; Failed to unmarshal json, error at position %d (\"%s\")", err, t.Offset, SafeSlice(string(jsonStr), int(t.Offset - 10), int(t.Offset + 10)))
+		default:
+			return nil, fmt.Errorf("%w; Failed to unmarshal json", err)
+		}
 	}
 
 	return overrides, nil

diff --git a/client/db.go b/client/db.go
@@ -3,6 +3,7 @@ package client
 import (
 	"encoding/json"
 	"errors"
+	"fmt"
 	"io/ioutil"
 )
 
@@ -59,11 +60,16 @@ func loadDB(dbFile string) (ConfigstoreDB, error) {
 
 	jsonStr, err := ioutil.ReadFile(dbFile)
 	if err != nil {
-		return ConfigstoreDB{}, err
+		return ConfigstoreDB{}, fmt.Errorf("%w; Failed to load DB file: %s", err, dbFile)
 	}
 
 	if err := json.Unmarshal(jsonStr, &db); err != nil {
-		return ConfigstoreDB{}, err
+		switch t := err.(type) {
+		case *json.SyntaxError:
+			return ConfigstoreDB{}, fmt.Errorf("%w; Failed to unmarshal json from DB file \"%s\", error at position %d (\"%s\")", err, dbFile, t.Offset, SafeSlice(string(jsonStr), int(t.Offset - 10), int(t.Offset + 10)))
+		default:
+			return ConfigstoreDB{}, fmt.Errorf("%w; Failed to unmarshal json from DB file \"%s\"", err, dbFile)
+		}
 	}
 
 	return db.validate()

diff --git a/client/helpers.go b/client/helpers.go
@@ -0,0 +1,19 @@
+package client
+
+func SafeSlice(str string, start int, end int) string {
+	if len(str) == 0 {
+		return str
+	}
+
+	s := start
+	if s < 0 {
+		s = 0
+	}
+
+	e := end
+	if e > len(str) {
+		e = len(str)
+	}
+
+	return str[s:e]
+}
diff --git a/cmd/configstore/shared.go b/cmd/configstore/shared.go
@@ -130,13 +130,19 @@ func ParseEnv(s string, basedir string, validate bool) (Env, error) {
 func LoadEnvOverride(basedir string) (map[string]string, error) {
 	var overrides = make(map[string]string)
 
-	jsonStr, err := ioutil.ReadFile(basedir + "/override.json")
+	path := basedir + "/override.json"
+	jsonStr, err := ioutil.ReadFile(path)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("%w; Failed to load override file: %s", err, path)
 	}
 
 	if err := json.Unmarshal(jsonStr, &overrides); err != nil {
-		return nil, err
+		switch t := err.(type) {
+		case *json.SyntaxError:
+			return nil, fmt.Errorf("%w; Failed to unmarshal json for subenv \"%s\", error at position %d (\"%s\")", err, basedir, t.Offset, client.SafeSlice(string(jsonStr), int(t.Offset - 10), int(t.Offset + 10)))
+		default:
+			return nil, fmt.Errorf("%w; Failed to unmarshal json for subenv \"%s\"", err)
+		}
 	}
 
 	return overrides, nil