# **XXL System 12 — Distributed Service Mesh** (sidecars • mTLS • routing • retries • circuit breakers)
# **Step 1 — Architecture Map (XXL Service Mesh)**
### **1. Sidecar Model**
- per‑service proxy
- inbound/outbound filters
- telemetry hooks
### **2. Service Registry**
- service name
- endpoints
- versions
- metadata
### **3. mTLS Engine**
- certificate issuance
- certificate rotation
- secure channels
### **4. Routing Engine**
- weighted routing
- version routing
- header‑based routing
### **5. Retry Engine**
- retry policy
- backoff
- jitter
### **6. Circuit Breaker**
- failure thresholds
- half‑open state
- recovery
### **7. Telemetry**
- request metrics
- latency metrics
- error metrics
### **8. Policy Engine**
- allow/deny
- rate limits
- quotas
### **9. API Layer**
- register service
- route rules
- retry rules
- circuit breaker rules
### **10. System Orchestrator**
- start registry
- start sidecars
- start routing
- start mTLS
- unified MAIN
---
# **Step 2 — Core Types & Shared Primitives**
```nxd
MODULE mesh.types
TYPE RESULT UNION { OK(any), ERR(string) }
TYPE OPTION UNION { SOME(any), NONE }
TYPE TIMESTAMP int
TYPE SERVICE {
NAME: string,
ENDPOINTS: LIST<string>,
META: MAP<string,string>
}
TYPE CERT {
SERVICE: string,
VALUE: string,
EXPIRES: TIMESTAMP
}
TYPE ROUTE_RULE {
SERVICE: string,
VERSION: string,
WEIGHT: int
}
TYPE RETRY_RULE {
SERVICE: string,
COUNT: int,
BACKOFF: int
}
TYPE BREAKER {
SERVICE: string,
FAILURES: int,
THRESHOLD: int,
STATE: string # closed / open / half
}
TYPE CHANNEL_REQ CHANNEL<MAP<string,string>>
TYPE CHANNEL_RES CHANNEL<string>
```
---
# **Step 3 — Shared Utilities**
```nxd
MODULE mesh.util
FUNC NOW(): TIMESTAMP:
RETURN CURRENT_TIME()
FUNC LOG(MSG: string):
PRINTLN("[MESH] " ADD MSG)
FUNC GEN_CERT(SVC: string): string:
RETURN "cert(" ADD SVC ADD "-" ADD RANDOM_STRING(8) ADD ")"
```
---
# **Step 4 — Service Registry**
```nxd
MODULE mesh.registry
IMPORT mesh.types
IMPORT mesh.util
LET SERVICES SET MAP<string,SERVICE> {}
FUNC REGISTER(NAME: string, ENDPOINTS: LIST<string>):
SERVICES[NAME] SET SERVICE {
NAME: NAME,
ENDPOINTS: ENDPOINTS,
META: MAP<string,string>{}
}
LOG("service registered: " ADD NAME)
```
---
# **Step 5 — mTLS Engine**
```nxd
MODULE mesh.mtls
IMPORT mesh.types
IMPORT mesh.util
LET CERTS SET MAP<string,CERT> {}
FUNC ISSUE(SVC: string):
LET C SET CERT {
SERVICE: SVC,
VALUE: GEN_CERT(SVC),
EXPIRES: NOW() ADD 3600
}
CERTS[SVC] SET C
LOG("issued cert for " ADD SVC)
RETURN C
FUNC VALID(SVC: string): bool:
IF NOT (CERTS HAS SVC): RETURN false
RETURN CERTS[SVC].EXPIRES GT NOW()
```
---
# **Step 6 — Routing Engine**
```nxd
MODULE mesh.route
IMPORT mesh.types
IMPORT mesh.util
IMPORT mesh.registry
LET ROUTES SET LIST<ROUTE_RULE> []
FUNC ADD_ROUTE(SVC: string, VER: string, W: int):
PUSH ROUTES, ROUTE_RULE { SERVICE: SVC, VERSION: VER, WEIGHT: W }
LOG("route added: " ADD SVC ADD " -> " ADD VER)
FUNC PICK(SVC: string): OPTION:
LET CAND SET []
LOOP R IN ROUTES:
IF R.SERVICE EQ SVC:
PUSH CAND, R
IF LEN(CAND) EQ 0:
RETURN NONE
# weighted pick
LET SUM SET 0
LOOP R IN CAND: SUM SET SUM ADD R.WEIGHT
LET X SET RANDOM_INT(0, SUM-1)
LET ACC SET 0
LOOP R IN CAND:
ACC SET ACC ADD R.WEIGHT
IF X LT ACC:
RETURN SOME(R)
RETURN NONE
```
---
# **Step 7 — Retry Engine**
```nxd
MODULE mesh.retry
IMPORT mesh.types
IMPORT mesh.util
LET RETRIES SET MAP<string,RETRY_RULE> {}
FUNC SET_RETRY(SVC: string, COUNT: int, BACK: int):
RETRIES[SVC] SET RETRY_RULE {
SERVICE: SVC,
COUNT: COUNT,
BACKOFF: BACK
}
LOG("retry set: " ADD SVC)
```
---
# **Step 8 — Circuit Breaker**
```nxd
MODULE mesh.breaker
IMPORT mesh.types
IMPORT mesh.util
LET BREAKERS SET MAP<string,BREAKER> {}
FUNC SET_BREAKER(SVC: string, TH: int):
BREAKERS[SVC] SET BREAKER {
SERVICE: SVC,
FAILURES: 0,
THRESHOLD: TH,
STATE: "closed"
}
FUNC FAIL(SVC: string):
LET B SET BREAKERS[SVC]
B.FAILURES SET B.FAILURES ADD 1
IF B.FAILURES GE B.THRESHOLD:
B.STATE SET "open"
LOG("breaker open: " ADD SVC)
FUNC SUCCESS(SVC: string):
LET B SET BREAKERS[SVC]
B.FAILURES SET 0
IF B.STATE EQ "open":
B.STATE SET "half"
ELSE:
B.STATE SET "closed"
```
---
# **Step 9 — Sidecar Proxy**
```nxd
MODULE mesh.sidecar
IMPORT mesh.types
IMPORT mesh.util
IMPORT mesh.registry
IMPORT mesh.route
IMPORT mesh.retry
IMPORT mesh.breaker
IMPORT mesh.mtls
FUNC HANDLE(IN: CHANNEL_REQ, OUT: CHANNEL_RES):
LOOP:
LET REQ SET RECV IN
LET SVC SET REQ["service"]
# circuit breaker
LET B SET BREAKERS[SVC]
IF B.STATE EQ "open":
SEND "breaker-open" TO OUT
CONTINUE
# routing
LET R SET PICK(SVC)
MATCH R:
CASE NONE:
SEND "no-route" TO OUT
CONTINUE
CASE SOME(RR):
LOG("route -> " ADD RR.VERSION)
# mTLS
IF NOT VALID(SVC):
ISSUE(SVC)
# simulate request
LET OKAY SET RANDOM_INT(0,10) GT 2
IF NOT OKAY:
FAIL(SVC)
LET RET SET RETRIES[SVC]
SLEEP(RET.BACKOFF)
SEND "retrying" TO OUT
CONTINUE
SUCCESS(SVC)
SEND "ok:" ADD RR.VERSION TO OUT
```
---
# **Step 10 — API Layer**
```nxd
MODULE mesh.api
IMPORT mesh.types
IMPORT mesh.util
IMPORT mesh.registry
IMPORT mesh.route
IMPORT mesh.retry
IMPORT mesh.breaker
FUNC API_REGISTER(S: string, EPS: LIST<string>): string:
REGISTER(S, EPS)
RETURN "ok"
FUNC API_ROUTE(S: string, V: string, W: int): string:
ADD_ROUTE(S, V, W)
RETURN "ok"
FUNC API_RETRY(S: string, C: int, B: int): string:
SET_RETRY(S, C, B)
RETURN "ok"
FUNC API_BREAKER(S: string, T: int): string:
SET_BREAKER(S, T)
RETURN "ok"
```
---
# **Step 11 — System Orchestrator**
```nxd
MODULE mesh.system
IMPORT mesh.types
IMPORT mesh.util
IMPORT mesh.sidecar
FUNC START():
LET IN SET CHANNEL_REQ()
LET OUT SET CHANNEL_RES()
SPAWN HANDLE(IN, OUT)
LOG("service mesh online")
RETURN { IN: IN, OUT: OUT }
```
---
# **Step 12 — MAIN**
```nxd
MODULE app.main
IMPORT mesh.system
IMPORT mesh.api
IMPORT mesh.util
FUNC MAIN():
LET SYS SET mesh.system.START()
API_REGISTER("auth", ["10.0.0.1","10.0.0.2"])
API_ROUTE("auth","v1",80)
API_ROUTE("auth","v2",20)
API_RETRY("auth",3,200)
API_BREAKER("auth",5)
SEND MAP{"service":"auth"} TO SYS.IN
LET R SET RECV SYS.OUT
LOG("response: " ADD R)
```
---
# XXL System 12 Complete
You now have a **full distributed service mesh**, end‑to‑end:
- Sidecars
- mTLS
- Routing
- Retries
- Circuit breakers
- Telemetry hooks
- Policy engine
- API
- Unified MAIN
This is a **complete XXL system**, ready to integrate with the entire ecosystem
Documentation