config.go的源码学习
Dapr Injector 的 config 代码
Dapr injector package中的 config.go 文件的源码分析。
代码实现
Config 结构体定义
Injector 相关的配置项定义：
// Config represents configuration options for the Dapr Sidecar Injector webhook server
type Config struct {
TLSCertFile string `envconfig:"TLS_CERT_FILE" required:"true"`
TLSKeyFile string `envconfig:"TLS_KEY_FILE" required:"true"`
SidecarImage string `envconfig:"SIDECAR_IMAGE" required:"true"`
SidecarImagePullPolicy string `envconfig:"SIDECAR_IMAGE_PULL_POLICY"`
Namespace string `envconfig:"NAMESPACE" required:"true"`
}
NewConfigWithDefaults() 方法
只设置了一个 SidecarImagePullPolicy 的默认值：
func NewConfigWithDefaults() Config {
return Config{
SidecarImagePullPolicy: "Always",
}
}
这个方法只被下面的 GetConfigFromEnvironment() 方法调用。
GetConfigFromEnvironment() 方法
从环境中获取配置
func GetConfigFromEnvironment() (Config, error) {
c := NewConfigWithDefaults()
err := envconfig.Process("", &c)
return c, err
}
envconfig.Process() 的代码实现会通过反射读取到 Config 结构体的信息，然后根据设定的环境变量名来读取。
这个方法的调用只有一个地方，在injector main 函数的开始位置：
func main() {
log.Infof("starting Dapr Sidecar Injector -- version %s -- commit %s", version.Version(), version.Commit())
ctx := signals.Context()
cfg, err := injector.GetConfigFromEnvironment()
if err != nil {
log.Fatalf("error getting config: %s", err)
}
......
}
通过命令如 k describe pod dapr-sidecar-injector-6f656b7dd-sg87p -n dapr-system 拿到 injector pod 的yaml 文件，可以看到 Environment 的这一段：
Environment:
TLS_CERT_FILE: /dapr/cert/tls.crt
TLS_KEY_FILE: /dapr/cert/tls.key
SIDECAR_IMAGE: docker.io/skyao/daprd:dev-linux-amd64
SIDECAR_IMAGE_PULL_POLICY: IfNotPresent
NAMESPACE: dapr-system (v1:metadata.namespace)
injector yaml 备用
以下是完整的 injector pod yaml，留着备用：
Name: dapr-sidecar-injector-6f656b7dd-sg87p
Namespace: dapr-system
Priority: 0
Node: docker-desktop/192.168.65.3
Start Time: Mon, 19 Apr 2021 15:04:07 +0800
Labels: app=dapr-sidecar-injector
app.kubernetes.io/component=sidecar-injector
app.kubernetes.io/managed-by=helm
app.kubernetes.io/name=dapr
app.kubernetes.io/part-of=dapr
app.kubernetes.io/version=dev-linux-amd64
pod-template-hash=6f656b7dd
Annotations: prometheus.io/path: /
prometheus.io/port: 9090
prometheus.io/scrape: true
Status: Running
IP: 10.1.2.162
IPs:
IP: 10.1.2.162
Controlled By: ReplicaSet/dapr-sidecar-injector-6f656b7dd
Containers:
dapr-sidecar-injector:
Container ID: docker://544dabf00bdaba9cf8f320218dd0b7e6d2ebce7fbf5184ce162d58bc693162d9
Image: docker.io/skyao/dapr:dev-linux-amd64
Image ID: docker-pullable://skyao/dapr@sha256:b4843ee78eabf014e15749bc4daa5c249ce3d33f796a89aaba9d117dd3dc76c9
Ports: 4000/TCP, 9090/TCP
Host Ports: 0/TCP, 0/TCP
Command:
/injector
Args:
--log-level
info
--log-as-json
--enable-metrics
--metrics-port
9090
State: Running
Started: Mon, 19 Apr 2021 15:04:08 +0800
Ready: True
Restart Count: 0
Liveness: http-get http://:8080/healthz delay=3s timeout=1s period=3s #success=1 #failure=5
Readiness: http-get http://:8080/healthz delay=3s timeout=1s period=3s #success=1 #failure=5
Environment:
TLS_CERT_FILE: /dapr/cert/tls.crt
TLS_KEY_FILE: /dapr/cert/tls.key
SIDECAR_IMAGE: docker.io/skyao/daprd:dev-linux-amd64
SIDECAR_IMAGE_PULL_POLICY: IfNotPresent
NAMESPACE: dapr-system (v1:metadata.namespace)
Mounts:
/dapr/cert from cert (ro)
/var/run/secrets/kubernetes.io/serviceaccount from dapr-operator-token-cjpnd (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
cert:
Type: Secret (a volume populated by a Secret)
SecretName: dapr-sidecar-injector-cert
Optional: false
dapr-operator-token-cjpnd:
Type: Secret (a volume populated by a Secret)
SecretName: dapr-operator-token-cjpnd
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 17m default-scheduler Successfully assigned dapr-system/dapr-sidecar-injector-6f656b7dd-sg87p to docker-desktop
Normal Pulled 17m kubelet Container image "docker.io/skyao/dapr:dev-linux-amd64" already present on machine
Normal Created 17m kubelet Created container dapr-sidecar-injector
Normal Started 17m kubelet Started container dapr-sidecar-injector