add service include regex option

cmd/nixose/main.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"regexp"
 	"strings"
 	"time"
 
@@ -18,6 +19,7 @@ var envFilesOnly = flag.Bool("env_files_only", false, "only use env files in the
 var output = flag.String("output", "", "path to output Nix file")
 var project = flag.String("project", "", "project name used as a prefix for generated resources")
 var projectSeparator = flag.String("project_separator", nixose.DefaultProjectSeparator, "seperator for project prefix")
+var serviceInclude = flag.String("service_include", "", "regex pattern for services to include")
 var autoStart = flag.Bool("auto_start", true, "control auto-start setting for containers")
 var runtime = flag.String("runtime", "podman", `"podman" or "docker"`)
 var useComposeLogDriver = flag.Bool("use_compose_log_driver", false, "if set, always use the Compose log driver.")
@@ -43,13 +45,23 @@ func main() {
 		log.Fatalf("Invalid --runtime: %q", *runtime)
 	}
 
+	var serviceIncludeRegexp *regexp.Regexp
+	if *serviceInclude != "" {
+		pat, err := regexp.Compile(*serviceInclude)
+		if err != nil {
+			log.Fatalf("Failed to parse -service_include pattern %q: %v", *serviceInclude, err)
+		}
+		serviceIncludeRegexp = pat
+	}
+
 	start := time.Now()
 	g := nixose.Generator{
 		Project:             nixose.NewProjectWithSeparator(*project, *projectSeparator),
 		Runtime:             containerRuntime,
 		Paths:               paths,
 		EnvFiles:            envFiles,
 		EnvFilesOnly:        *envFilesOnly,
+		ServiceInclude:      serviceIncludeRegexp,
 		AutoStart:           *autoStart,
 		UseComposeLogDriver: *useComposeLogDriver,
 	}

compose.go

@@ -154,6 +154,7 @@ type Generator struct {
 	Runtime             ContainerRuntime
 	Paths               []string
 	EnvFiles            []string
+	ServiceInclude      *regexp.Regexp
 	AutoStart           bool
 	EnvFilesOnly        bool
 	UseComposeLogDriver bool
@@ -326,6 +327,10 @@ func (g *Generator) buildNixContainer(service types.ServiceConfig) (*NixContaine
 func (g *Generator) buildNixContainers(composeProject *types.Project) ([]*NixContainer, error) {
 	var containers []*NixContainer
 	for _, s := range composeProject.Services {
+		if g.ServiceInclude != nil && !g.ServiceInclude.MatchString(s.Name) {
+			log.Printf("Skipping service %q due to include regex %q", s.Name, g.ServiceInclude.String())
+			continue
+		}
 		c, err := g.buildNixContainer(s)
 		if err != nil {
 			return nil, fmt.Errorf("failed to build container for service %q: %w", s.Name, err)