This patch adds support for a custom check id and name when
registering a service.
This is achieved by adding a CheckID and a Name field to the
CheckType structure which is used to register checks with a
service and when returning health check definitions.
CheckDefinition is a superset of CheckType which duplicates
some of the fields of CheckType. This patch decouples these
two structures by removing the embedding of CheckType in
CheckDefinition.
Fixes#3047
This patch removes duplicate internal copies of constants in the structs
package which are also defined in the api package. The api.KVOp type
with all its values for the TXN endpoint and the api.HealthXXX constants
are now used throughout the codebase.
This resulted in some circular dependencies in the testutil package
which have been resolved by copying code and constants and moving the
WaitForLeader function into a separate testrpc package.
This experiment was brought about because of variable naming
confusion where name and checkIDs were interchanged. Gave CheckID
an Qualified Type Name and chased downstream changes.
Consolidate code duplication and tests into a single lib package. Most of these functions were from various **/util.go functions that couldn't be imported due to cyclic imports. The consul/lib package is intended to be a terminal node in an import DAG and a place to stash various consul-only helper functions. Pulled in hashicorp/go-uuid instead of consolidating UUID access.
Adds the ability to simply check whether a TCP socket accepts
connections to determine if it is healthy. This is a light-weight -
though less comprehensive than scripting - method of checking network
service health.
The check parameter `tcp` should be set to the `address:port`
combination for the service to be tested. Supports both IPv6 and IPv4,
in the case of a hostname that resolves to both, connections will be
attempted via both protocol versions, with the first successful
connection returning a successful check result.
Example check:
```json
{
"check": {
"id": "ssh",
"name": "SSH (TCP)",
"tcp": "example.com:22",
"interval": "10s"
}
}
```
This status must be one of the valid check statuses: 'passing', 'warning', 'critical', 'unknown'.
If the status field is not present or the empty string, the default of 'critical' is used.
For long (>10s) interval checks the http timeout is 10s, otherwise thetimeout is the interval. This means that a check *should* return
before the next check begins.
Frank Schroeder