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env: rename methods and improve readability

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Signed-off-by: Paulo Pires <pjpires@gmail.com>
This commit is contained in:
Paulo Pires
2018-12-15 11:01:41 +00:00
parent 6f04b3102c
commit 8bcbbf58cd
1 changed files with 42 additions and 34 deletions
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76
vkubelet/env.go
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@@ -49,8 +49,7 @@ const (
)
// populateEnvironmentVariables populates the environment of each container (and init container) in the specified pod.
// NOTE: No other function in this file should be called from the outside.
// TODO: Make this the single exported function of a "pkg/environment" package in the future.
// TODO Make this the single exported function of a "pkg/environment" package in the future.
func populateEnvironmentVariables(ctx context.Context, pod *corev1.Pod, rm *manager.ResourceManager, recorder record.EventRecorder) error {
// Populate each init container's environment.
for idx := range pod.Spec.InitContainers {
@@ -70,29 +69,30 @@ func populateEnvironmentVariables(ctx context.Context, pod *corev1.Pod, rm *mana
// populateContainerEnvironment populates the environment of a single container in the specified pod.
func populateContainerEnvironment(ctx context.Context, pod *corev1.Pod, container *corev1.Container, rm *manager.ResourceManager, recorder record.EventRecorder) error {
// Create an "environment map" based on the value of the specified container's ".envFrom" field.
envOne, err := makeEnvironmentMapFromEnvFrom(ctx, pod, container, rm, recorder)
envFrom, err := makeEnvironmentMapBasedOnEnvFrom(ctx, pod, container, rm, recorder)
if err != nil {
return err
}
// Create an "environment map" based on the value of the specified container's ".env" field.
envTwo, err := makeEnvironmentMapFromEnv(ctx, pod, container, rm, recorder)
env, err := makeEnvironmentMapBasedOnEnv(ctx, pod, container, rm, recorder)
if err != nil {
return err
}
// Empty the container's ".envFrom" field and replace its ".env" field with the final, merged environment.
// Values in "envTwo" (sourced from ".env") will override any values with the same key defined in "envOne" (sourced from ".envFrom").
// Values in "env" (sourced from ".env") will override any values with the same key defined in "envFrom" (sourced from ".envFrom").
// This is in accordance with what the Kubelet itself does.
// https://github.com/kubernetes/kubernetes/blob/v1.13.0/pkg/kubelet/kubelet_pods.go#L557-L558
// https://github.com/kubernetes/kubernetes/blob/v1.13.1/pkg/kubelet/kubelet_pods.go#L557-L558
container.EnvFrom = []corev1.EnvFromSource{}
container.Env = makeEnvironment(envOne, envTwo)
container.Env = mergeEnvironments(envFrom, env)
return nil
}
// makeEnvironmentMapFromEnvFrom returns a map representing the resolved environment of the specified container after being populated from the entries in the ".envFrom" field.
func makeEnvironmentMapFromEnvFrom(ctx context.Context, pod *corev1.Pod, container *corev1.Container, rm *manager.ResourceManager, recorder record.EventRecorder) (map[string]string, error) {
// makeEnvironmentMapBasedOnEnvFrom returns a map representing the resolved environment of the specified container after being populated from the entries in the ".envFrom" field.
func makeEnvironmentMapBasedOnEnvFrom(ctx context.Context, pod *corev1.Pod, container *corev1.Container, rm *manager.ResourceManager, recorder record.EventRecorder) (map[string]string, error) {
// Create a map to hold the resulting environment.
res := make(map[string]string, 0)
// Iterate over "envFrom" references in order to populate the environment.
loop:
for _, envFrom := range container.EnvFrom {
switch {
// Handle population from a configmap.
@@ -114,7 +114,7 @@ func makeEnvironmentMapFromEnvFrom(ctx context.Context, pod *corev1.Pod, contain
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonFailedToReadOptionalConfigMap, "failed to read configmap %q", ef.Name)
}
// Continue on to the next reference.
continue
continue loop
}
// At this point we know the configmap reference is mandatory.
// Hence, we should return a meaningful error.
@@ -127,7 +127,9 @@ func makeEnvironmentMapFromEnvFrom(ctx context.Context, pod *corev1.Pod, contain
}
// At this point we have successfully fetched the target configmap.
// Iterate over the keys defined in the configmap and populate the environment accordingly.
// https://github.com/kubernetes/kubernetes/blob/v1.13.1/pkg/kubelet/kubelet_pods.go#L581-L595
invalidKeys := make([]string, 0)
mKeys:
for key, val := range m.Data {
// If a prefix has been defined, prepend it to the environment variable's name.
if len(envFrom.Prefix) > 0 {
@@ -137,7 +139,7 @@ func makeEnvironmentMapFromEnvFrom(ctx context.Context, pod *corev1.Pod, contain
// If it isn't, it should be appended to the list of invalid keys and skipped.
if errMsgs := apivalidation.IsEnvVarName(key); len(errMsgs) != 0 {
invalidKeys = append(invalidKeys, key)
continue
continue mKeys
}
// Add the key and its value to the environment.
res[key] = val
@@ -162,24 +164,26 @@ func makeEnvironmentMapFromEnvFrom(ctx context.Context, pod *corev1.Pod, contain
if errors.IsNotFound(err) {
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonOptionalSecretNotFound, "secret %q not found", ef.Name)
} else {
log.G(ctx).Warnf("failed to read configmap %q: %v", ef.Name, err)
log.G(ctx).Warnf("failed to read secret %q: %v", ef.Name, err)
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonFailedToReadOptionalSecret, "failed to read secret %q", ef.Name)
}
// Continue on to the next reference.
continue
continue loop
}
// At this point we know the secret reference is mandatory.
// Hence, we should return a meaningful error.
if errors.IsNotFound(err) {
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonMandatorySecretNotFound, "secret %q not found", ef.Name)
return nil, fmt.Errorf("configmap %q not found", ef.Name)
return nil, fmt.Errorf("secret %q not found", ef.Name)
}
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonFailedToReadMandatorySecret, "failed to read secret %q", ef.Name)
return nil, fmt.Errorf("failed to fetch configmap %q: %v", ef.Name, err)
return nil, fmt.Errorf("failed to fetch secret %q: %v", ef.Name, err)
}
// At this point we have successfully fetched the target secret.
// Iterate over the keys defined in the secret and populate the environment accordingly.
// https://github.com/kubernetes/kubernetes/blob/v1.13.1/pkg/kubelet/kubelet_pods.go#L581-L595
invalidKeys := make([]string, 0)
sKeys:
for key, val := range s.Data {
// If a prefix has been defined, prepend it to the environment variable's name.
if len(envFrom.Prefix) > 0 {
@@ -189,7 +193,7 @@ func makeEnvironmentMapFromEnvFrom(ctx context.Context, pod *corev1.Pod, contain
// If it isn't, it should be appended to the list of invalid keys and skipped.
if errMsgs := apivalidation.IsEnvVarName(key); len(errMsgs) != 0 {
invalidKeys = append(invalidKeys, key)
continue
continue sKeys
}
// Add the key and its value to the environment.
res[key] = string(val)
@@ -205,17 +209,18 @@ func makeEnvironmentMapFromEnvFrom(ctx context.Context, pod *corev1.Pod, contain
return res, nil
}
// makeEnvironmentMapFromEnv returns a map representing the resolved environment of the specified container after being populated from the entries in the ".env" field.
func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *corev1.Container, rm *manager.ResourceManager, recorder record.EventRecorder) (map[string]string, error) {
// makeEnvironmentMapBasedOnEnv returns a map representing the resolved environment of the specified container after being populated from the entries in the ".env" field.
func makeEnvironmentMapBasedOnEnv(ctx context.Context, pod *corev1.Pod, container *corev1.Container, rm *manager.ResourceManager, recorder record.EventRecorder) (map[string]string, error) {
// Create a map to hold the resolved environment variables.
res := make(map[string]string, len(container.Env))
// Iterate over environment variables in order to populate the map.
loop:
for _, env := range container.Env {
switch {
// Handle values that have been directly provided.
case env.Value != "":
res[env.Name] = env.Value
continue
continue loop
// Handle population from a configmap key.
case env.ValueFrom != nil && env.ValueFrom.ConfigMapKeyRef != nil:
// The environment variable must be set from a configmap.
@@ -223,10 +228,10 @@ func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *
// Check whether the key reference is optional.
// This will control whether we fail when unable to read the requested key.
optional := vf != nil && *vf.Optional
// Try to grab the referenced secret.
// Try to grab the referenced configmap.
m, err := rm.GetConfigMap(vf.Name, pod.Namespace)
if err != nil {
// We couldn't fetch the secret.
// We couldn't fetch the configmap.
// However, if the key reference is optional we should not fail.
if optional {
if errors.IsNotFound(err) {
@@ -236,7 +241,7 @@ func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonFailedToReadOptionalConfigMap, "skipping optional envvar %q: failed to read configmap %q", env.Name, vf.Name)
}
// Continue on to the next reference.
continue
continue loop
}
// At this point we know the key reference is mandatory.
// Hence, we should return a meaningful error.
@@ -259,7 +264,7 @@ func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *
if optional {
// Continue on to the next reference.
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonOptionalConfigMapKeyNotFound, "skipping optional envvar %q: key %q does not exist in configmap %q", env.Name, vf.Key, vf.Name)
continue
continue loop
}
// At this point we know the key reference is mandatory.
// Hence, we should fail.
@@ -268,7 +273,7 @@ func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *
}
// Populate the environment variable and continue on to the next reference.
res[env.Name] = keyValue
continue
continue loop
// Handle population from a secret key.
case env.ValueFrom != nil && env.ValueFrom.SecretKeyRef != nil:
vf := env.ValueFrom.SecretKeyRef
@@ -288,7 +293,7 @@ func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonFailedToReadOptionalSecret, "skipping optional envvar %q: failed to read secret %q", env.Name, vf.Name)
}
// Continue on to the next reference.
continue
continue loop
}
// At this point we know the key reference is mandatory.
// Hence, we should return a meaningful error.
@@ -311,7 +316,7 @@ func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *
if optional {
// Continue on to the next reference.
recorder.Eventf(pod, corev1.EventTypeWarning, ReasonOptionalSecretKeyNotFound, "skipping optional envvar %q: key %q does not exist in secret %q", env.Name, vf.Key, vf.Name)
continue
continue loop
}
// At this point we know the key reference is mandatory.
// Hence, we should fail.
@@ -320,30 +325,33 @@ func makeEnvironmentMapFromEnv(ctx context.Context, pod *corev1.Pod, container *
}
// Populate the environment variable and continue on to the next reference.
res[env.Name] = string(keyValue)
continue
continue loop
// Handle population from a field (downward API).
case env.ValueFrom != nil && env.ValueFrom.FieldRef != nil:
// TODO Implement the downward API.
continue
// https://github.com/virtual-kubelet/virtual-kubelet/issues/123
continue loop
// Handle population from a resource request/limit.
case env.ValueFrom != nil && env.ValueFrom.ResourceFieldRef != nil:
// TODO Implement populating resource requests.
continue
continue loop
}
}
// Return the populated environment.
return res, nil
}
// makeEnvironment creates the final environment for a container by merging the two specified "environment maps".
// Values in "envTwo" override any values with the same key defined in "envOne".
func makeEnvironment(envOne map[string]string, envTwo map[string]string) []corev1.EnvVar {
// mergeEnvironments creates the final environment for a container by merging "envFrom" and "env".
// Values in "env" override any values with the same key defined in "envFrom".
// This is in accordance with what the Kubelet itself does.
// https://github.com/kubernetes/kubernetes/blob/v1.13.1/pkg/kubelet/kubelet_pods.go#L557-L558
func mergeEnvironments(envFrom map[string]string, env map[string]string) []corev1.EnvVar {
tmp := make(map[string]string, 0)
res := make([]corev1.EnvVar, 0)
for key, val := range envOne {
for key, val := range envFrom {
tmp[key] = val
}
for key, val := range envTwo {
for key, val := range env {
tmp[key] = val
}
for key, val := range tmp {