175 lines
5.3 KiB
Plaintext
175 lines
5.3 KiB
Plaintext
---
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layout: commands
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page_title: 'Commands: KV Put'
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---
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# Consul KV Put
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Command: `consul kv put`
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The `kv put` command writes the data to the given path in the KV store.
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-> **Note**: When writing multiple entries at once, consider using
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[`kv import`](/commands/kv/import) instead. Alternatively, the
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[transaction API](/api-docs/txn) provides support for performing up to
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64 KV operations atomically.
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## Usage
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Usage: `consul kv put [options] KEY [DATA]`
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#### API Options
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@include 'http_api_options_client.mdx'
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@include 'http_api_options_server.mdx'
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#### Enterprise Options
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@include 'http_api_namespace_options.mdx'
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@include 'http_api_partition_options.mdx'
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#### KV Put Options
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- `-acquire` - Obtain a lock on the key. If the key does not exist, this
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operation will create the key and obtain the lock. The session must already
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exist and be specified via the -session flag. The default value is false.
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- `-base64` - Treat the data as base 64 encoded. The default value is false.
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- `-cas` - Perform a Check-And-Set operation. Specifying this value also
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requires the -modify-index flag to be set. The default value is false.
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- `-flags=<int>` - Unsigned integer value to assign to this KV pair. This
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value is not read by Consul, so clients can use this value however makes sense
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for their use case. The default value is 0 (no flags).
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- `-modify-index=<int>` - Unsigned integer representing the ModifyIndex of the
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key. This is used in combination with the -cas flag.
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- `-release` - Forfeit the lock on the key at the given path. This requires the
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-session flag to be set. The key must be held by the session in order to be
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unlocked. The default value is false.
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- `-session=<string>` - User-defined identifier for this session as a string.
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This is commonly used with the -acquire and -release operations to build
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robust locking, but it can be set on any key. The default value is empty (no
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session).
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## Examples
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To insert a value of "5" for the key named "redis/config/connections" in the
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KV store:
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```shell-session hideClipboard
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$ consul kv put redis/config/connections 5
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Success! Data written to: redis/config/connections
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```
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If no data is specified, the key will be created with empty data:
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```shell-session hideClipboard
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$ consul kv put redis/config/connections
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Success! Data written to: redis/config/connections
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```
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!> **Be careful of overwriting data!** The above operation would overwrite
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any existing value at the key to the empty value.
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### Base64 Encoded Values
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If the `-base64` flag is set, the given data will be Base64-decoded before writing:
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```shell-session hideClipboard
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$ consul kv put -base64 foo/encoded aGVsbG8gd29ybGQK
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Success! Data written to: foo/encoded
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```
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### Longer or Sensitive Values
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For longer or sensitive values, it is possible to read from a file by
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supplying its path prefixed with the `@` symbol:
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```shell-session hideClipboard
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$ consul kv put redis/config/password @password.txt
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Success! Data written to: redis/config/password
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```
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Or read values from stdin by specifying the `-` symbol:
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```shell-session hideClipboard
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$ echo "5" | consul kv put redis/config/connections -
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Success! Data written to: redis/config/connections
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```
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```shell-session hideClipboard
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$ consul kv put redis/config/connections -
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5
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<CTRL+D>
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Success! Data written to: redis/config/connections
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```
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```shell-session hideClipboard
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$ consul kv put leaderboard/scores - <<EOF
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{
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"user-a": 100,
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"user-b": 250,
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"user-c": 75
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}
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EOF
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Success! Data written to: leaderboard/scores
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```
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~> **Warning**: For secret and sensitive values, you should consider using a
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secret management solution like **[HashiCorp's Vault](https://learn.hashicorp.com/tutorials/vault/static-secrets?in=vault/secrets-management)**.
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While it is possible to encrpyt data before writing it to Consul's KV store,
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Consul provides no built-in support for encryption at-rest.
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### Atomic Check-And-Set (CAS)
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To only update a key if it has not been modified since a given index, specify
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the `-cas` and `-modify-index` flags:
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```shell-session hideClipboard
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$ consul kv get -detailed redis/config/connections | grep ModifyIndex
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ModifyIndex 456
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$ consul kv put -cas -modify-index=123 redis/config/connections 10
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Error! Did not write to redis/config/connections: CAS failed
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$ consul kv put -cas -modify-index=456 redis/config/connections 10
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Success! Data written to: redis/config/connections
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```
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### Locking Primitives
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To create or tune a lock, use the `-acquire` and `-session` flags. The session must already exist (this command will not create it or manage it):
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```shell-session hideClipboard
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$ consul kv put -acquire -session=abc123 redis/lock/update
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Success! Lock acquired on: redis/lock/update
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```
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When you are finished, release the lock:
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```shell-session hideClipboard
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$ consul kv put -release -session=acb123 redis/lock/update
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Success! Lock released on: redis/lock/update
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```
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~> **Warning!** If you are trying to build a locking mechanism with these
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low-level primitives, you may want to look at the [<tt>consul
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lock</tt>](/commands/lock) command. It provides higher-level
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functionality without exposing the internal APIs of Consul.
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### Flags
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To set user-defined flags on the entry, use the `-flags` option. These flags
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are completely controlled by the user and have no special meaning to Consul:
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```shell-session hideClipboard
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$ consul kv put -flags=42 redis/config/password s3cr3t
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Success! Data written to: redis/config/password
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```
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