316 lines
12 KiB
Plaintext
316 lines
12 KiB
Plaintext
---
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layout: api
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page_title: Transaction - HTTP API
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description: >-
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The /txn endpoint manages multiple operations in Consul, including catalog
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updates and fetches of multiple KV entries inside a single, atomic
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transaction.
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---
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# Transactions HTTP API
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The `/txn` endpoint manages multiple operations in Consul, including catalog
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updates and fetches of multiple KV entries inside a single, atomic
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transaction.
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## Create Transaction
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This endpoint permits submitting a list of operations to apply to Consul
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inside of a transaction. If any operation fails, the transaction is rolled back
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and none of the changes are applied.
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If the transaction does not contain any write operations then it will be
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fast-pathed internally to an endpoint that works like other reads, except that
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blocking queries are not currently supported. In this mode, you may supply the
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`?stale` or `?consistent` query parameters with the request to control
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consistency. To support bounding the acceptable staleness of data, read-only
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transaction responses provide the `X-Consul-LastContact` header containing the
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time in milliseconds that a server was last contacted by the leader node. The
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`X-Consul-KnownLeader` header also indicates if there is a known leader. These
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won't be present if the transaction contains any write operations, and any
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consistency query parameters will be ignored, since writes are always managed by
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the leader via the Raft consensus protocol.
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| Method | Path | Produces |
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| ------ | ------ | ------------------ |
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| `PUT` | `/txn` | `application/json` |
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The table below shows this endpoint's support for
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[blocking queries](/api-docs/features/blocking),
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[consistency modes](/api-docs/features/consistency),
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[agent caching](/api-docs/features/caching), and
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[required ACLs](/api#authentication).
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| Blocking Queries | Consistency Modes | Agent Caching | ACL Required |
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| ---------------- | ----------------- | ------------- | ---------------------------------------------------------------------------------------------- |
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| `NO` | `all`<sup>1</sup> | `none` | `key:read,key:write`<br />`node:read,node:write`<br />`service:read,service:write`<sup>2</sup> |
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<p>
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<sup>1</sup> For read-only transactions
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<br />
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<sup>2</sup> The ACL required depends on the operations in the transaction.
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</p>
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### Parameters
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- `dc` `(string: "")` - Specifies the datacenter to query. This will default
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to the datacenter of the agent being queried. This is specified as part of the
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URL as a query parameter.
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- `KV` operations have the following fields:
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- `Verb` `(string: <required>)` - Specifies the type of operation to perform.
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Please see the table below for available verbs.
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- `Key` `(string: <required>)` - Specifies the full path of the entry.
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- `Value` `(string: "")` - Specifies a **base64-encoded** blob of data. Values
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cannot be larger than 512kB.
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- `Flags` `(int: 0)` - Specifies an opaque unsigned integer that can be
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attached to each entry. Clients can choose to use this however makes sense
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for their application.
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- `Index` `(int: 0)` - Specifies an index. See the table below for more
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information.
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- `Session` `(string: "")` - Specifies a session. See the table below for more
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information.
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- `Namespace` `(string: "")` <EnterpriseAlert inline /> - Specifies the namespace to
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create the KV data If not provided, the namespace will be inherited from the
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request's ACL token or will default to the `default` namespace. Added in Consul 1.7.0.
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- `Node` operations have the following fields:
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- `Verb` `(string: <required>)` - Specifies the type of operation to perform.
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- `Node` `(Node: <required>)` - Specifies the node information to use
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for the operation. See the [catalog endpoint](/api-docs/catalog#parameters) for the fields in this object. Note the only the node can be specified here, not any services or checks - separate service or check operations must be used for those.
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- `Service` operations have the following fields:
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- `Verb` `(string: <required>)` - Specifies the type of operation to perform.
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- `Node` `(string: <required>)` = Specifies the name of the node to use for
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this service operation.
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- `Service` `(Service: <required>)` - Specifies the service instance information to use
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for the operation. See the [catalog endpoint](/api-docs/catalog#parameters) for the fields in this object.
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- `Check` operations have the following fields:
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- `Verb` `(string: <required>)` - Specifies the type of operation to perform.
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- `Check` `(Service: <required>)` - Specifies the check to use
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for the operation. See the [catalog endpoint](/api-docs/catalog#parameters) for the fields in this object.
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Please see the table below for available verbs.
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### Sample Payload
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The body of the request should be a list of operations to perform inside the
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atomic transaction. Up to 64 operations may be present in a single transaction.
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```json
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[
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{
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"KV": {
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"Verb": "<verb>",
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"Key": "<key>",
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"Value": "<Base64-encoded blob of data>",
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"Flags": <flags>,
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"Index": <index>,
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"Session": "<session id>"
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}
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},
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{
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"Node": {
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"Verb": "set",
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"Node": {
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"ID": "67539c9d-b948-ba67-edd4-d07a676d6673",
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"Node": "bar",
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"Address": "192.168.0.1",
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"Datacenter": "dc1",
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"Meta": {
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"instance_type": "m2.large"
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}
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}
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}
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},
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{
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"Service": {
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"Verb": "delete",
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"Node": "foo",
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"Service": {
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"ID": "db1"
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}
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}
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},
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{
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"Check": {
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"Verb": "cas",
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"Check": {
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"Node": "bar",
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"CheckID": "service:web1",
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"Name": "Web HTTP Check",
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"Status": "critical",
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"ServiceID": "web1",
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"ServiceName": "web",
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"ServiceTags": null,
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"Definition": {
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"HTTP": "http://localhost:8080",
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"Interval": "10s"
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},
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"ModifyIndex": 22
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}
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}
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}
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]
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```
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### Sample Request
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```shell-session
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$ curl \
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--request PUT \
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--data @payload.json \
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http://127.0.0.1:8500/v1/txn
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```
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### Sample Response
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If the transaction can be processed, a status code of 200 will be returned if it
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was successfully applied, or a status code of 409 will be returned if it was
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rolled back. If either of these status codes are returned, the response will
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look like this:
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```json
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{
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"Results": [
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{
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"KV": {
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"LockIndex": <lock index>,
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"Key": "<key>",
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"Flags": <flags>,
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"Value": "<Base64-encoded blob of data, or null>",
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"CreateIndex": <index>,
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"ModifyIndex": <index>
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}
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},
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{
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"Node": {
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"ID": "67539c9d-b948-ba67-edd4-d07a676d6673",
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"Node": "bar",
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"Address": "192.168.0.1",
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"Datacenter": "dc1",
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"TaggedAddresses": null,
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"Meta": {
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"instance_type": "m2.large"
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},
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"CreateIndex": 32,
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"ModifyIndex": 32
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}
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},
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{
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"Check": {
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"Node": "bar",
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"CheckID": "service:web1",
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"Name": "Web HTTP Check",
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"Status": "critical",
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"Notes": "",
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"Output": "",
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"ServiceID": "web1",
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"ServiceName": "web",
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"ServiceTags": null,
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"Definition": {
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"HTTP": "http://localhost:8080",
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"Interval": "10s"
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},
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"CreateIndex": 22,
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"ModifyIndex": 35
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}
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}
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],
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"Errors": [
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{
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"OpIndex": <index of failed operation>,
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"What": "<error message for failed operation>"
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},
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...
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]
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}
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```
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- `Results` has entries for some operations if the transaction was successful.
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To save space, the `Value` for KV results will be `null` for any `Verb` other than "get" or
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"get-tree". Like the `/v1/kv/<key>` endpoint, `Value` will be Base64-encoded
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if it is present. Also, no result entries will be added for verbs that delete
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keys.
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- `Errors` has entries describing which operations failed if the transaction was
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rolled back. The `OpIndex` gives the index of the failed operation in the
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transaction, and `What` is a string with an error message about why that
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operation failed.
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### Tables of Operations
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#### KV Operations
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The following tables summarize the available verbs and the fields that apply to
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those operations ("X" means a field is required and "O" means it is optional):
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| Verb | Operation | Key | Value | Flags | Index | Session |
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| ------------------ | --------------------------------------- | :-: | :---: | :---: | :---: | :-----: |
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| `set` | Sets the `Key` to the given `Value` | `x` | `x` | `o` | | |
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| `cas` | Sets, but with CAS semantics | `x` | `x` | `o` | `x` | |
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| `lock` | Lock with the given `Session` | `x` | `x` | `o` | | `x` |
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| `unlock` | Unlock with the given `Session` | `x` | `x` | `o` | | `x` |
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| `get` | Get the key, fails if it does not exist | `x` | | | | |
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| `get-tree` | Gets all keys with the prefix | `x` | | | | |
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| `check-index` | Fail if modify index != index | `x` | | | `x` | |
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| `check-session` | Fail if not locked by session | `x` | | | | `x` |
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| `check-not-exists` | Fail if key exists | `x` | | | | |
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| `delete` | Delete the key | `x` | | | | |
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| `delete-tree` | Delete all keys with a prefix | `x` | | | | |
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| `delete-cas` | Delete, but with CAS semantics | `x` | | | `x` | |
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#### Node Operations
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Node operations act on an individual node and require either a Node ID or name, giving precedence
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to the ID if both are set. Delete operations will not return a result on success.
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| Verb | Operation |
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| ------------ | -------------------------------------------------------- |
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| `set` | Sets the node to the given state |
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| `cas` | Sets, but with CAS semantics using the given ModifyIndex |
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| `get` | Get the node, fails if it does not exist |
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| `delete` | Delete the node |
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| `delete-cas` | Delete, but with CAS semantics |
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#### Service Operations
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Service operations act on an individual service instance on the given node name. Both a node name
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and valid service name are required. Delete operations will not return a result on success.
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| Verb | Operation |
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| ------------ | -------------------------------------------------------- |
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| `set` | Sets the service to the given state |
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| `cas` | Sets, but with CAS semantics using the given ModifyIndex |
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| `get` | Get the service, fails if it does not exist |
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| `delete` | Delete the service |
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| `delete-cas` | Delete, but with CAS semantics |
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#### Check Operations
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Check operations act on an individual health check instance on the given node name. Both a node name
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and valid check ID are required. Delete operations will not return a result on success.
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| Verb | Operation |
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| ------------ | -------------------------------------------------------- |
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| `set` | Sets the health check to the given state |
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| `cas` | Sets, but with CAS semantics using the given ModifyIndex |
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| `get` | Get the check, fails if it does not exist |
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| `delete` | Delete the check |
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| `delete-cas` | Delete, but with CAS semantics |
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