Update max container name length (nektos#1597)

* Update max container name length

Signed-off-by: Aidan Jensen <aidan@artificial.com>

* Use hashed name instead to prevent conflicts

Signed-off-by: Aidan Jensen <aidan@artificial.com>

---------

Signed-off-by: Aidan Jensen <aidan@artificial.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/runner/run_context.go

@@ -5,6 +5,7 @@ import (
 	"bufio"
 	"context"
 	"crypto/rand"
+	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
@@ -505,26 +506,16 @@ func mergeMaps(maps ...map[string]string) map[string]string {
 }
 
 func createContainerName(parts ...string) string {
-	name := make([]string, 0)
+	name := strings.Join(parts, "-")
 	pattern := regexp.MustCompile("[^a-zA-Z0-9]")
-	partLen := (30 / len(parts)) - 1
-	for i, part := range parts {
-		if i == len(parts)-1 {
-			name = append(name, pattern.ReplaceAllString(part, "-"))
-		} else {
-			// If any part has a '-<number>' on the end it is likely part of a matrix job.
-			// Let's preserve the number to prevent clashes in container names.
-			re := regexp.MustCompile("-[0-9]+$")
-			num := re.FindStringSubmatch(part)
-			if len(num) > 0 {
-				name = append(name, trimToLen(pattern.ReplaceAllString(part, "-"), partLen-len(num[0])))
-				name = append(name, num[0])
-			} else {
-				name = append(name, trimToLen(pattern.ReplaceAllString(part, "-"), partLen))
-			}
-		}
-	}
-	return strings.ReplaceAll(strings.Trim(strings.Join(name, "-"), "-"), "--", "-")
+	name = pattern.ReplaceAllString(name, "-")
+	name = strings.ReplaceAll(name, "--", "-")
+	hash := sha256.Sum256([]byte(name))
+
+	// SHA256 is 64 hex characters. So trim name to 63 characters to make room for the hash and separator
+	trimmedName := strings.Trim(trimToLen(name, 63), "-")
+
+	return fmt.Sprintf("%s-%x", trimmedName, hash)
 }
 
 func trimToLen(s string, l int) string {