feat(volume): add "exchange volumes"

This volumes are "emptyDir" and can have init command. For example, in a
"same-pod", it allow the user to copy data from image to a directory
that is mounted on others pods.

generator/chart.go

@@ -209,10 +209,21 @@ func (chart *HelmChart) generateDeployment(service types.ServiceConfig, deployme
 	// generate the cronjob if needed
 	chart.setCronJob(service, appName)
 
+	if exchange, ok := service.Labels[labels.LabelExchangeVolume]; ok {
+		// we need to add a volume and a mount point
+		ex, err := labelStructs.NewExchangeVolumes(exchange)
+		if err != nil {
+			return err
+		}
+		for _, exchangeVolume := range ex {
+			d.AddLegacyVolume("exchange-"+exchangeVolume.Name, exchangeVolume.Type)
+			d.exchangesVolumes[service.Name] = exchangeVolume
+		}
+	}
+
 	// get the same-pod label if exists, add it to the list.
 	// We later will copy some parts to the target deployment and remove this one.
 	if samePod, ok := service.Labels[labels.LabelSamePod]; ok && samePod != "" {
-		log.Printf("Found same-pod label for %s", service.Name)
 		podToMerge[samePod] = &service
 	}
 

generator/deployment.go

@@ -39,6 +39,7 @@ type Deployment struct {
 	service            *types.ServiceConfig                    `yaml:"-"`
 	defaultTag         string                                  `yaml:"-"`
 	isMainApp          bool                                    `yaml:"-"`
+	exchangesVolumes   map[string]*labelStructs.ExchangeVolume `yaml:"-"`
 }
 
 // NewDeployment creates a new Deployment from a compose service. The appName is the name of the application taken from the project name.
@@ -92,6 +93,7 @@ func NewDeployment(service types.ServiceConfig, chart *HelmChart) *Deployment {
 		},
 		configMaps:       make(map[string]*ConfigMapMount),
 		volumeMap:        make(map[string]string),
+		exchangesVolumes: map[string]*labelStructs.ExchangeVolume{},
 	}
 
 	// add containers
@@ -212,6 +214,27 @@ func (d *Deployment) AddVolumes(service types.ServiceConfig, appName string) {
 	}
 }
 
+func (d *Deployment) AddLegacyVolume(name, kind string) {
+	// ensure the volume is not present
+	for _, v := range d.Spec.Template.Spec.Volumes {
+		if v.Name == name {
+			return
+		}
+	}
+
+	// init
+	if d.Spec.Template.Spec.Volumes == nil {
+		d.Spec.Template.Spec.Volumes = []corev1.Volume{}
+	}
+
+	d.Spec.Template.Spec.Volumes = append(d.Spec.Template.Spec.Volumes, corev1.Volume{
+		Name: name,
+		VolumeSource: corev1.VolumeSource{
+			EmptyDir: &corev1.EmptyDirVolumeSource{},
+		},
+	})
+}
+
 func (d *Deployment) BindFrom(service types.ServiceConfig, binded *Deployment) {
 	// find the volume in the binded deployment
 	for _, bindedVolume := range binded.Spec.Template.Spec.Volumes {
@@ -276,14 +299,27 @@ func (d *Deployment) Filename() string {
 }
 
 // SetEnvFrom sets the environment variables to a configmap. The configmap is created.
-func (d *Deployment) SetEnvFrom(service types.ServiceConfig, appName string) {
+func (d *Deployment) SetEnvFrom(service types.ServiceConfig, appName string, samePod ...bool) {
 	if len(service.Environment) == 0 {
 		return
 	}
+	inSamePod := false
+	if len(samePod) > 0 && samePod[0] {
+		inSamePod = true
+	}
 
 	drop := []string{}
 	secrets := []string{}
 
+	defer func() {
+		c, index := d.BindMapFilesToContainer(service, secrets, appName)
+		if c == nil || index == -1 {
+			log.Println("Container not found for service ", service.Name)
+			return
+		}
+		d.Spec.Template.Spec.Containers[index] = *c
+	}()
+
 	// secrets from label
 	labelSecrets, err := labelStructs.SecretsFrom(service.Labels[labels.LabelSecrets])
 	if err != nil {
@@ -308,6 +344,10 @@ func (d *Deployment) SetEnvFrom(service types.ServiceConfig, appName string) {
 		secrets = append(secrets, secret)
 	}
 
+	if inSamePod {
+		return
+	}
+
 	// for each values from label "values", add it to Values map and change the envFrom
 	// value to {{ .Values.<service>.<value> }}
 	for _, value := range labelValues {
@@ -330,10 +370,26 @@ func (d *Deployment) SetEnvFrom(service types.ServiceConfig, appName string) {
 	for _, value := range drop {
 		delete(service.Environment, value)
 	}
+}
 
+func (d *Deployment) BindMapFilesToContainer(service types.ServiceConfig, secrets []string, appName string) (*corev1.Container, int) {
 	fromSources := []corev1.EnvFromSource{}
 
-	if len(service.Environment) > 0 {
+	envSize := len(service.Environment)
+
+	for _, secret := range secrets {
+		for k := range service.Environment {
+			if k == secret {
+				envSize--
+			}
+		}
+	}
+
+	if envSize > 0 {
+		if service.Name == "db" {
+			log.Println("Service ", service.Name, " has environment variables")
+			log.Println(service.Environment)
+		}
 		fromSources = append(fromSources, corev1.EnvFromSource{
 			ConfigMapRef: &corev1.ConfigMapEnvSource{
 				LocalObjectReference: corev1.LocalObjectReference{
@@ -356,7 +412,7 @@ func (d *Deployment) SetEnvFrom(service types.ServiceConfig, appName string) {
 	container, index := utils.GetContainerByName(service.Name, d.Spec.Template.Spec.Containers)
 	if container == nil {
 		utils.Warn("Container not found for service " + service.Name)
-		return
+		return nil, -1
 	}
 
 	container.EnvFrom = append(container.EnvFrom, fromSources...)
@@ -364,8 +420,30 @@ func (d *Deployment) SetEnvFrom(service types.ServiceConfig, appName string) {
 	if container.Env == nil {
 		container.Env = []corev1.EnvVar{}
 	}
+	return container, index
+}
 
-	d.Spec.Template.Spec.Containers[index] = *container
+func (d *Deployment) MountExchangeVolumes() {
+	for name, ex := range d.exchangesVolumes {
+		for i, c := range d.Spec.Template.Spec.Containers {
+			c.VolumeMounts = append(c.VolumeMounts, corev1.VolumeMount{
+				Name:      "exchange-" + ex.Name,
+				MountPath: ex.MountPath,
+			})
+			if len(ex.Init) > 0 && name == c.Name {
+				d.Spec.Template.Spec.InitContainers = append(d.Spec.Template.Spec.InitContainers, corev1.Container{
+					Command: []string{"/bin/sh", "-c", ex.Init},
+					Image:   c.Image,
+					Name:    "exhange-init-" + name,
+					VolumeMounts: []corev1.VolumeMount{{
+						Name:      "exchange-" + ex.Name,
+						MountPath: ex.MountPath,
+					}},
+				})
+			}
+			d.Spec.Template.Spec.Containers[i] = c
+		}
+	}
 }
 
 // Yaml returns the yaml representation of the deployment.

generator/generator.go

@@ -79,6 +79,11 @@ func Generate(project *types.Project) (*HelmChart, error) {
 		}
 	}
 
+	// if we have built exchange volumes, we need to moint them in each deployment
+	for _, d := range deployments {
+		d.MountExchangeVolumes()
+	}
+
 	// drop all "same-pod" deployments because the containers and volumes are already
 	// in the target deployment
 	for _, service := range podToMerge {
@@ -87,7 +92,10 @@ func Generate(project *types.Project) (*HelmChart, error) {
 			if target, ok := deployments[samepod]; ok {
 				target.AddContainer(*service)
 				target.BindFrom(*service, deployments[service.Name])
-				target.SetEnvFrom(*service, appName)
+				target.SetEnvFrom(*service, appName, true)
+				// copy all init containers
+				initContainers := deployments[service.Name].Spec.Template.Spec.InitContainers
+				target.Spec.Template.Spec.InitContainers = append(target.Spec.Template.Spec.InitContainers, initContainers...)
 				delete(deployments, service.Name)
 			} else {
 				log.Printf("service %[1]s is declared as %[2]s, but %[2]s is not defined", service.Name, labels.LabelSamePod)

generator/katenaryfile/main.go

@@ -39,6 +39,7 @@ type Service struct {
 	MapEnv          *labelStructs.MapEnv           `json:"map-env,omitempty" jsonschema:"title=Map Env,description=Map environment variables to another value"`
 	CronJob         *labelStructs.CronJob          `json:"cron-job,omitempty" jsonschema:"title=Cron Job,description=Cron Job configuration"`
 	EnvFrom         *labelStructs.EnvFrom          `json:"env-from,omitempty" jsonschema:"title=Env From,description=Inject environment variables from another service"`
+	ExchangeVolumes []*labelStructs.ExchangeVolume `json:"exchange-volumes,omitempty" jsonschema:"title=Exchange Volumes,description=Exchange volumes between services"`
 }
 
 // OverrideWithConfig overrides the project with the katenary.yaml file. It
@@ -89,6 +90,7 @@ func OverrideWithConfig(project *types.Project) {
 			getLabelContent(s.MapEnv, &project.Services[i], labels.LabelMapEnv)
 			getLabelContent(s.CronJob, &project.Services[i], labels.LabelCronJob)
 			getLabelContent(s.EnvFrom, &project.Services[i], labels.LabelEnvFrom)
+			getLabelContent(s.ExchangeVolumes, &project.Services[i], labels.LabelExchangeVolume)
 		}
 	}
 	fmt.Println(utils.IconInfo, "Katenary file loaded successfully, the services are now configured.")

generator/labels/katenaryLabels.go

@@ -32,6 +32,7 @@ const (
 	LabelConfigMapFiles Label = KatenaryLabelPrefix + "/configmap-files"
 	LabelCronJob        Label = KatenaryLabelPrefix + "/cronjob"
 	LabelEnvFrom        Label = KatenaryLabelPrefix + "/env-from"
+	LabelExchangeVolume Label = KatenaryLabelPrefix + "/exchange-volumes"
 )
 
 var (

generator/labels/katenaryLabelsDoc.yaml

@@ -284,4 +284,40 @@
         {{ .KatenaryPrefix }}/env-from: |-
             - myservice1
 
+"exchange-volumes":
+  short: Add exchange volumes (empty directory on the node) to share data
+  type: "list of objects"
+  long: |-
+    This label allows sharing data between containres. The volume is created in 
+    the node and mounted in the pod. It is useful to share data between containers
+    in a "same pod" logic. For example to let PHP-FPM and Nginx share the same direcotory.
+
+    This will create:
+    - an `emptyDir` volume in the deployment
+    - a `voumeMount` in the pod for **each container**
+    - a `initContainer` for each definition
+
+    Fields:
+      - name: the name of the volume (manadatory)
+      - mountPath: the path where the volume is mounted in the pod (optional, default is `/opt`)
+      - init: a command to run to initialize the volume with data (optional)
+
+    !!! Warning
+        This is highly experimental. This is mainly useful when using the "same-pod" label.
+
+  example: |-
+    nginx:
+      # ...
+      labels;
+        {{ .KatenaryPrefix }}/exchange-volumes: |-
+          - name: php-fpm
+            mountPath: /var/www/html
+    php:
+      # ...
+      labels:
+        {{ .KatenaryPrefix }}/exchange-volumes: |-
+          - name: php-fpm
+            mountPath: /opt
+            init: cp -ra /var/www/html/* /opt
+
 # vim: ft=gotmpl.yaml

generator/labels/labelStructs/exchangeVolume.go

@@ -0,0 +1,20 @@
+package labelStructs
+
+import "gopkg.in/yaml.v3"
+
+type ExchangeVolume struct {
+	Name      string `yaml:"name" json:"name"`
+	MountPath string `yaml:"mountPath" json:"mountPath"`
+	Type      string `yaml:"type,omitempty" json:"type,omitempty"`
+	Init      string `yaml:"init,omitempty" json:"init,omitempty"`
+}
+
+func NewExchangeVolumes(data string) ([]*ExchangeVolume, error) {
+	mapping := []*ExchangeVolume{}
+
+	if err := yaml.Unmarshal([]byte(data), &mapping); err != nil {
+		return nil, err
+	}
+
+	return mapping, nil
+}