open-consul/website/pages/api-docs/discovery-chain.mdx

566 lines
15 KiB
Plaintext
Raw Normal View History

2020-04-06 20:27:35 +00:00
---
layout: api
page_title: Discovery Chain - HTTP API
sidebar_title: Discovery Chain
2020-04-07 18:55:19 +00:00
description: The /discovery-chain endpoints are for interacting with the discovery chain.
2020-04-06 20:27:35 +00:00
---
-> **1.6.0+:** The discovery chain API is available in Consul versions 1.6.0 and newer.
# Discovery Chain HTTP Endpoint
~> This is a low-level API primarily targeted at developers building external
2020-04-09 23:46:54 +00:00
[Connect proxy integrations](/docs/connect/proxies/integrate). Future
2020-04-06 20:27:35 +00:00
high-level proxy integration APIs may obviate the need for this API over time.
The `/discovery-chain` endpoint returns the compiled [discovery
2020-04-09 23:46:54 +00:00
chain](/docs/internals/discovery-chain) for a service.
2020-04-06 20:27:35 +00:00
This will fetch all related [configuration
2020-04-09 23:46:54 +00:00
entries](/docs/agent/config_entries) and render them into a form suitable
for use by a [connect proxy](/docs/connect/proxies) implementation. This
2020-04-06 20:27:35 +00:00
is a key component of [L7 Traffic
2020-04-09 23:46:54 +00:00
Management](/docs/connect/l7-traffic-management).
2020-04-06 20:27:35 +00:00
## Read Compiled Discovery Chain
If overrides are needed they are passed as the JSON-encoded request body and
the `POST` method must be used, otherwise `GET` is sufficient.
| Method | Path | Produces |
| ------------------ | --------------------------- | ------------------ |
| `GET` | `/discovery-chain/:service` | `application/json` |
| `POST`<sup>1</sup> | `/discovery-chain/:service` | `application/json` |
2020-04-07 18:55:19 +00:00
<p>
<sup>1</sup> Both GET and POST are for <strong>read</strong> operations. GET
requests do not permit request bodies so a POST is required if override
parameters are needed.
</p>
2020-04-06 20:27:35 +00:00
The table below shows this endpoint's support for
2020-04-09 23:46:54 +00:00
[blocking queries](/api/features/blocking),
[consistency modes](/api/features/consistency),
[agent caching](/api/features/caching), and
2020-04-09 23:20:00 +00:00
[required ACLs](/api#authentication).
2020-04-06 20:27:35 +00:00
| Blocking Queries | Consistency Modes | Agent Caching | ACL Required |
| ---------------- | ----------------- | -------------------- | -------------- |
| `YES` | `all` | `background refresh` | `service:read` |
### URL Parameters
- `service` `(string: <required>)` - Specifies the service to query when
compiling the discovery chain. This is provided as part of the URL.
- `compile-dc` `(string: "")` - Specifies the datacenter to use as the basis of
compilation. This will default to the datacenter of the agent being queried.
This is specified as part of the URL as a query parameter.
This value comes from an [upstream
2020-04-09 23:46:54 +00:00
configuration](/docs/connect/registration/service-registration#upstream-configuration-reference)
[`datacenter`](/docs/connect/registration/service-registration#datacenter)
2020-04-06 20:27:35 +00:00
parameter.
### POST Body Parameters
- `OverrideConnectTimeout` `(duration: 0s)` - Overrides the final [connect
2020-04-09 23:46:54 +00:00
timeout](/docs/agent/config-entries/service-resolver#connecttimeout) for
2020-04-06 20:27:35 +00:00
any service resolved in the compiled chain.
This value comes from the `connect_timeout_ms` key in an [upstream
2020-04-09 23:46:54 +00:00
configuration](/docs/connect/registration/service-registration#upstream-configuration-reference)
2020-04-06 20:27:35 +00:00
opaque
2020-04-09 23:46:54 +00:00
[`config`](/docs/connect/registration/service-registration#config-1)
2020-04-06 20:27:35 +00:00
parameter.
- `OverrideProtocol` `(string: "")` - Overrides the final
2020-04-09 23:46:54 +00:00
[protocol](/docs/agent/config-entries/service-defaults#protocol) used in
2020-04-06 20:27:35 +00:00
the compiled discovery chain.
If the chain ordinarily would be TCP and an L7 protocol is passed here the
chain will still not include Routers or Splitters. If the chain ordinarily
would be L7 and TCP is passed here the chain will not include Routers or
Splitters.
This value comes from the `protocol` key in an [upstream
2020-04-09 23:46:54 +00:00
configuration](/docs/connect/registration/service-registration#upstream-configuration-reference)
2020-04-06 20:27:35 +00:00
opaque
2020-04-09 23:46:54 +00:00
[`config`](/docs/connect/registration/service-registration#config-1)
2020-04-06 20:27:35 +00:00
parameter.
- `OverrideMeshGateway` `(MeshGatewayConfig: <optional>)` - Overrides the final
2020-04-09 23:46:54 +00:00
[mesh gateway configuration](/docs/connect/mesh_gateway#connect-proxy-configuration)
2020-04-06 20:27:35 +00:00
for this any service resolved in the compiled chain.
This value comes from either the [proxy
2020-04-09 23:46:54 +00:00
configuration](/docs/connect/registration/service-registration#complete-configuration-example)
[`mesh_gateway`](/docs/connect/registration/service-registration#mesh_gateway)
2020-04-06 20:27:35 +00:00
parameter or an [upstream
2020-04-09 23:46:54 +00:00
configuration](/docs/connect/registration/service-registration#upstream-configuration-reference)
[`mesh_gateway`](/docs/connect/registration/service-registration#mesh_gateway-1)
2020-04-06 20:27:35 +00:00
parameter. If both are present the value defined on the upstream is used.
- `Mode` `(string: "")` - One of `none`, `local`, or `remote`.
### Sample Compilations
Full documentation for the output fields is found on the [discovery chain
2020-04-09 23:46:54 +00:00
internals](/docs/internals/discovery-chain#compileddiscoverychain)
2020-04-06 20:27:35 +00:00
page.
#### Multi-Datacenter Failover
Config entries defined:
```hcl
kind = "service-resolver"
name = "web"
connect_timeout = "15s"
failover = {
"*" = {
datacenters = ["dc3", "dc4"]
}
}
```
Request:
```text
$ curl http://127.0.0.1:8500/v1/discovery-chain/web
```
Response:
```json
{
"Chain": {
"ServiceName": "web",
"Namespace": "default",
"Datacenter": "dc1",
"Protocol": "tcp",
"StartNode": "resolver:web.default.dc1",
"Nodes": {
"resolver:web.default.dc1": {
"Type": "resolver",
"Name": "web.default.dc1",
"Resolver": {
"ConnectTimeout": "15s",
"Target": "web.default.dc1",
"Failover": {
"Targets": ["web.default.dc3", "web.default.dc4"]
}
}
}
},
"Targets": {
"web.default.dc1": {
"ID": "web.default.dc1",
"Service": "web",
"Namespace": "default",
"Datacenter": "dc1",
"MeshGateway": {},
"Subset": {},
"SNI": "web.default.dc1.internal.47e25151-6212-ba25-8b7e-81adbbbab461.consul",
"Name": "web.default.dc1.internal.47e25151-6212-ba25-8b7e-81adbbbab461.consul"
},
"web.default.dc3": {
"ID": "web.default.dc3",
"Service": "web",
"Namespace": "default",
"Datacenter": "dc3",
"MeshGateway": {},
"Subset": {},
"SNI": "web.default.dc3.internal.47e25151-6212-ba25-8b7e-81adbbbab461.consul",
"Name": "web.default.dc3.internal.47e25151-6212-ba25-8b7e-81adbbbab461.consul"
},
"web.default.dc4": {
"ID": "web.default.dc4",
"Service": "web",
"Namespace": "default",
"Datacenter": "dc4",
"MeshGateway": {},
"Subset": {},
"SNI": "web.default.dc4.internal.47e25151-6212-ba25-8b7e-81adbbbab461.consul",
"Name": "web.default.dc4.internal.47e25151-6212-ba25-8b7e-81adbbbab461.consul"
}
}
}
}
```
#### Datacenter Redirect with Overrides
Config entries defined:
```hcl
kind = "service-resolver"
name = "web"
redirect {
datacenter = "dc2"
}
```
Request:
```text
$ curl -X POST \
-d'
{
"OverrideConnectTimeout": "7s",
"OverrideProtocol": "grpc",
"OverrideMeshGateway": {
"Mode": "remote"
}
}
' http://127.0.0.1:8500/v1/discovery-chain/web
```
Response:
```json
{
"Chain": {
"ServiceName": "web",
"Namespace": "default",
"Datacenter": "dc1",
"CustomizationHash": "b94f529a",
"Protocol": "grpc",
"StartNode": "resolver:web.default.dc2",
"Nodes": {
"resolver:web.default.dc2": {
"Type": "resolver",
"Name": "web.default.dc2",
"Resolver": {
"ConnectTimeout": "7s",
"Target": "web.default.dc2"
}
}
},
"Targets": {
"web.default.dc2": {
"ID": "web.default.dc2",
"Service": "web",
"Namespace": "default",
"Datacenter": "dc2",
"MeshGateway": {
"Mode": "remote"
},
"Subset": {},
"SNI": "web.default.dc2.internal.59c17fd4-8dfa-f54a-ae71-855b26faf637.consul",
"Name": "web.default.dc2.internal.59c17fd4-8dfa-f54a-ae71-855b26faf637.consul"
}
}
}
}
```
#### Version Split For Alternate Datacenter
Config entries defined:
```hcl
kind = "service-resolver"
name = "web"
default_subset = "v1"
subsets = {
"v1" = {
filter = "Service.Meta.version == v1"
}
"v2" = {
filter = "Service.Meta.version == v2"
}
}
# ---------------------------
kind = "service-defaults"
name = "web"
protocol = "http"
# ---------------------------
kind = "service-splitter"
name = "web"
splits = [
{
weight = 90
service_subset = "v1"
},
{
weight = 10
service_subset = "v2"
},
]
```
Request:
```text
$ curl http://127.0.0.1:8500/v1/discovery-chain/web?compile-dc=dc2
```
Response:
```json
{
"Chain": {
"ServiceName": "web",
"Namespace": "default",
"Datacenter": "dc2",
"Protocol": "http",
"StartNode": "splitter:web",
"Nodes": {
"resolver:v1.web.default.dc2": {
"Type": "resolver",
"Name": "v1.web.default.dc2",
"Resolver": {
"ConnectTimeout": "5s",
"Target": "v1.web.default.dc2"
}
},
"resolver:v2.web.default.dc2": {
"Type": "resolver",
"Name": "v2.web.default.dc2",
"Resolver": {
"ConnectTimeout": "5s",
"Target": "v2.web.default.dc2"
}
},
"splitter:web": {
"Type": "splitter",
"Name": "web",
"Splits": [
{
"Weight": 90,
"NextNode": "resolver:v1.web.default.dc2"
},
{
"Weight": 10,
"NextNode": "resolver:v2.web.default.dc2"
}
]
}
},
"Targets": {
"v1.web.default.dc2": {
"ID": "v1.web.default.dc2",
"Service": "web",
"ServiceSubset": "v1",
"Namespace": "default",
"Datacenter": "dc2",
"MeshGateway": {},
"Subset": {
"Filter": "Service.Meta.version == v1"
},
"SNI": "v1.web.default.dc2.internal.6c9594ec-d798-28b9-d084-aa03e81cf078.consul",
"Name": "v1.web.default.dc2.internal.6c9594ec-d798-28b9-d084-aa03e81cf078.consul"
},
"v2.web.default.dc2": {
"ID": "v2.web.default.dc2",
"Service": "web",
"ServiceSubset": "v2",
"Namespace": "default",
"Datacenter": "dc2",
"MeshGateway": {},
"Subset": {
"Filter": "Service.Meta.version == v2"
},
"SNI": "v2.web.default.dc2.internal.6c9594ec-d798-28b9-d084-aa03e81cf078.consul",
"Name": "v2.web.default.dc2.internal.6c9594ec-d798-28b9-d084-aa03e81cf078.consul"
}
}
}
}
```
#### HTTP Path Routing
Config entries defined:
```hcl
kind = "service-resolver"
name = "web"
subsets = {
"canary" = {
filter = "Service.Meta.flavor == canary"
}
}
# ---------------------------
kind = "proxy-defaults"
name = "web"
config {
protocol = "http"
}
# ---------------------------
kind = "service-router"
name = "web"
routes = [
{
match {
http {
path_prefix = "/admin"
}
}
destination {
service = "admin"
prefix_rewrite = "/"
request_timeout = "15s"
}
},
{
match {
http {
header = [
{
name = "x-debug"
exact = "1"
},
]
}
}
destination {
service = "web"
service_subset = "canary"
num_retries = 5
retry_on_connect_failure = true
retry_on_status_codes = [401, 409]
}
},
]
```
Request:
```text
$ curl http://127.0.0.1:8500/v1/discovery-chain/web
```
Response:
```json
{
"Chain": {
"ServiceName": "web",
"Namespace": "default",
"Datacenter": "dc1",
"Protocol": "http",
"StartNode": "router:web",
"Nodes": {
"resolver:admin.default.dc1": {
"Type": "resolver",
"Name": "admin.default.dc1",
"Resolver": {
"ConnectTimeout": "5s",
"Default": true,
"Target": "admin.default.dc1"
}
},
"resolver:canary.web.default.dc1": {
"Type": "resolver",
"Name": "canary.web.default.dc1",
"Resolver": {
"ConnectTimeout": "5s",
"Target": "canary.web.default.dc1"
}
},
"resolver:web.default.dc1": {
"Type": "resolver",
"Name": "web.default.dc1",
"Resolver": {
"ConnectTimeout": "5s",
"Target": "web.default.dc1"
}
},
"router:web": {
"Type": "router",
"Name": "web",
"Routes": [
{
"Definition": {
"Match": {
"HTTP": {
"PathPrefix": "/admin"
}
},
"Destination": {
"RequestTimeout": "15s",
"Service": "admin",
"PrefixRewrite": "/"
}
},
"NextNode": "resolver:admin.default.dc1"
},
{
"Definition": {
"Match": {
"HTTP": {
"Header": [
{
"Name": "x-debug",
"Exact": "1"
}
]
}
},
"Destination": {
"Service": "web",
"ServiceSubset": "canary",
"NumRetries": 5,
"RetryOnConnectFailure": true,
"RetryOnStatusCodes": [401, 409]
}
},
"NextNode": "resolver:canary.web.default.dc1"
},
{
"Definition": {
"Match": {
"HTTP": {
"PathPrefix": "/"
}
},
"Destination": {
"Service": "web"
}
},
"NextNode": "resolver:web.default.dc1"
}
]
}
},
"Targets": {
"admin.default.dc1": {
"ID": "admin.default.dc1",
"Service": "admin",
"Namespace": "default",
"Datacenter": "dc1",
"MeshGateway": {},
"Subset": {},
"SNI": "admin.default.dc1.internal.fce8a058-0981-2c04-d23c-b7375af64ce8.consul",
"Name": "admin.default.dc1.internal.fce8a058-0981-2c04-d23c-b7375af64ce8.consul"
},
"canary.web.default.dc1": {
"ID": "canary.web.default.dc1",
"Service": "web",
"ServiceSubset": "canary",
"Namespace": "default",
"Datacenter": "dc1",
"MeshGateway": {},
"Subset": {
"Filter": "Service.Meta.flavor == canary"
},
"SNI": "canary.web.default.dc1.internal.fce8a058-0981-2c04-d23c-b7375af64ce8.consul",
"Name": "canary.web.default.dc1.internal.fce8a058-0981-2c04-d23c-b7375af64ce8.consul"
},
"web.default.dc1": {
"ID": "web.default.dc1",
"Service": "web",
"Namespace": "default",
"Datacenter": "dc1",
"MeshGateway": {},
"Subset": {},
"SNI": "web.default.dc1.internal.fce8a058-0981-2c04-d23c-b7375af64ce8.consul",
"Name": "web.default.dc1.internal.fce8a058-0981-2c04-d23c-b7375af64ce8.consul"
}
}
}
}
```