From aeaca72df65f5841473f4f1ac8925242496aa95a Mon Sep 17 00:00:00 2001
From: Ben Meier <ben.meier@humanitec.com>
Date: Thu, 1 Feb 2024 11:45:47 +0000
Subject: [PATCH] feat: added support for multiple containers in the same
 network

---
 internal/compose/convert.go      | 78 ++++++++++++++++++++------------
 internal/compose/convert_test.go | 52 +++++++++++++++++++++
 2 files changed, 102 insertions(+), 28 deletions(-)

diff --git a/internal/compose/convert.go b/internal/compose/convert.go
index 1663fa8..84dc904 100644
--- a/internal/compose/convert.go
+++ b/internal/compose/convert.go
@@ -10,6 +10,7 @@ package compose
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"sort"
 
 	compose "github.com/compose-spec/compose-go/types"
@@ -23,29 +24,51 @@ func ConvertSpec(spec *score.WorkloadSpec) (*compose.Project, ExternalVariables,
 		return nil, nil, fmt.Errorf("preparing context: %w", err)
 	}
 
-	for _, cSpec := range spec.Containers {
+	if len(spec.Containers) == 0 {
+		return nil, nil, errors.New("workload does not have any containers to convert into a compose service")
+	}
+
+	var project = compose.Project{
+		Services: make(compose.Services, 0, len(spec.Containers)),
+	}
+
+	externalVars := ExternalVariables(ctx.ListEnvVars())
+
+	var ports []compose.ServicePortConfig
+	if len(spec.Service.Ports) > 0 {
+		ports = []compose.ServicePortConfig{}
+		for _, pSpec := range spec.Service.Ports {
+			var pubPort = fmt.Sprintf("%v", pSpec.Port)
+			var tgtPort = pSpec.TargetPort
+			if pSpec.TargetPort == 0 {
+				tgtPort = pSpec.Port
+			}
+			ports = append(ports, compose.ServicePortConfig{
+				Published: pubPort,
+				Target:    uint32(tgtPort),
+				Protocol:  pSpec.Protocol,
+			})
+		}
+	}
+
+	// When multiple containers are specified we need to identify one container as the "main" container which will own
+	// the network and use the native workload name. All other containers in this workload will have the container
+	// name appended as a suffix. We use the natural sort order of the container names and pick the first one
+	containerNames := make([]string, 0, len(spec.Containers))
+	for name := range spec.Containers {
+		containerNames = append(containerNames, name)
+	}
+	slices.Sort(containerNames)
+
+	for _, containerName := range containerNames {
+		cSpec := spec.Containers[containerName]
+
 		var env = make(compose.MappingWithEquals, len(cSpec.Variables))
 		for key, val := range cSpec.Variables {
 			var envVarVal = ctx.Substitute(val)
 			env[key] = &envVarVal
 		}
 
-		var ports []compose.ServicePortConfig
-		if len(spec.Service.Ports) > 0 {
-			ports = []compose.ServicePortConfig{}
-			for _, pSpec := range spec.Service.Ports {
-				var pubPort = fmt.Sprintf("%v", pSpec.Port)
-				var tgtPort = pSpec.TargetPort
-				if pSpec.TargetPort == 0 {
-					tgtPort = pSpec.Port
-				}
-				ports = append(ports, compose.ServicePortConfig{
-					Published: pubPort,
-					Target:    uint32(tgtPort),
-					Protocol:  pSpec.Protocol,
-				})
-			}
-		}
 		// NOTE: Sorting is necessary for DeepEqual call within our Unit Tests to work reliably
 		sort.Slice(ports, func(i, j int) bool {
 			return ports[i].Published < ports[j].Published
@@ -83,18 +106,17 @@ func ConvertSpec(spec *score.WorkloadSpec) (*compose.Project, ExternalVariables,
 			Volumes:     volumes,
 		}
 
-		var proj = compose.Project{
-			Services: compose.Services{
-				svc,
-			},
+		if len(spec.Containers) > 1 {
+			// if we have more than 1 container then namespace them with the container name
+			svc.Name += "-" + containerName
+			// if we are not the "first" service, then inherit the network from the first service
+			if len(project.Services) > 0 {
+				svc.Ports = nil
+				svc.NetworkMode = "service:" + project.Services[0].Name
+			}
 		}
 
-		var externalVars = ExternalVariables(ctx.ListEnvVars())
-
-		// NOTE: Only one container per workload can be defined for compose.
-		//       All other containers will be ignored by this tool.
-		return &proj, externalVars, nil
+		project.Services = append(project.Services, svc)
 	}
-
-	return nil, nil, errors.New("workload does not have any containers to convert into a compose service")
+	return &project, externalVars, nil
 }
diff --git a/internal/compose/convert_test.go b/internal/compose/convert_test.go
index 5122074..1e61f7b 100644
--- a/internal/compose/convert_test.go
+++ b/internal/compose/convert_test.go
@@ -163,6 +163,58 @@ func TestScoreConvert(t *testing.T) {
 				"APP_DB_NAME": "",
 			},
 		},
+		{
+			Name: "Should support multiple containers",
+			Source: &score.WorkloadSpec{
+				Metadata: score.WorkloadMeta{
+					Name: "test",
+				},
+				Containers: score.ContainersSpecs{
+					"frontend": score.ContainerSpec{
+						Image: "busybox",
+						Variables: map[string]string{
+							"PORT": "80",
+						},
+					},
+					"backend": score.ContainerSpec{
+						Image: "busybox",
+						Variables: map[string]string{
+							"PORT": "81",
+						},
+					},
+				},
+				Service: score.ServiceSpec{
+					Ports: map[string]score.ServicePortSpec{
+						"frontend": {Port: 8080, TargetPort: 80},
+						"backend":  {Port: 8081, TargetPort: 81},
+					},
+				},
+			},
+			Project: &compose.Project{
+				Services: compose.Services{
+					{
+						Name:  "test-backend",
+						Image: "busybox",
+						Environment: compose.MappingWithEquals{
+							"PORT": stringPtr("81"),
+						},
+						Ports: []compose.ServicePortConfig{
+							{Target: 80, Published: "8080"},
+							{Target: 81, Published: "8081"},
+						},
+					},
+					{
+						Name:  "test-frontend",
+						Image: "busybox",
+						Environment: compose.MappingWithEquals{
+							"PORT": stringPtr("80"),
+						},
+						NetworkMode: "service:test-backend",
+					},
+				},
+			},
+			Vars: ExternalVariables{},
+		},
 
 		// Errors handling
 		//