ServiceDiscovery / Client / discover_instances
discover_instances#
- ServiceDiscovery.Client.discover_instances(**kwargs)#
Discovers registered instances for a specified namespace and service. You can use
DiscoverInstances
to discover instances for any type of namespace.DiscoverInstances
returns a randomized list of instances allowing customers to distribute traffic evenly across instances. For public and private DNS namespaces, you can also use DNS queries to discover instances.See also: AWS API Documentation
Request Syntax
response = client.discover_instances( NamespaceName='string', ServiceName='string', MaxResults=123, QueryParameters={ 'string': 'string' }, OptionalParameters={ 'string': 'string' }, HealthStatus='HEALTHY'|'UNHEALTHY'|'ALL'|'HEALTHY_OR_ELSE_ALL' )
- Parameters:
NamespaceName (string) –
[REQUIRED]
The
HttpName
name of the namespace. It’s found in theHttpProperties
member of theProperties
member of the namespace.ServiceName (string) –
[REQUIRED]
The name of the service that you specified when you registered the instance.
MaxResults (integer) – The maximum number of instances that you want Cloud Map to return in the response to a
DiscoverInstances
request. If you don’t specify a value forMaxResults
, Cloud Map returns up to 100 instances.QueryParameters (dict) –
Filters to scope the results based on custom attributes for the instance (for example,
{version=v1, az=1a}
). Only instances that match all the specified key-value pairs are returned.(string) –
(string) –
OptionalParameters (dict) –
Opportunistic filters to scope the results based on custom attributes. If there are instances that match both the filters specified in both the
QueryParameters
parameter and this parameter, all of these instances are returned. Otherwise, the filters are ignored, and only instances that match the filters that are specified in theQueryParameters
parameter are returned.(string) –
(string) –
HealthStatus (string) –
The health status of the instances that you want to discover. This parameter is ignored for services that don’t have a health check configured, and all instances are returned.
HEALTHY
Returns healthy instances.
UNHEALTHY
Returns unhealthy instances.
ALL
Returns all instances.
HEALTHY_OR_ELSE_ALL
Returns healthy instances, unless none are reporting a healthy state. In that case, return all instances. This is also called failing open.
- Return type:
dict
- Returns:
Response Syntax
{ 'Instances': [ { 'InstanceId': 'string', 'NamespaceName': 'string', 'ServiceName': 'string', 'HealthStatus': 'HEALTHY'|'UNHEALTHY'|'UNKNOWN', 'Attributes': { 'string': 'string' } }, ], 'InstancesRevision': 123 }
Response Structure
(dict) –
Instances (list) –
A complex type that contains one
HttpInstanceSummary
for each registered instance.(dict) –
In a response to a DiscoverInstances request,
HttpInstanceSummary
contains information about one instance that matches the values that you specified in the request.InstanceId (string) –
The ID of an instance that matches the values that you specified in the request.
NamespaceName (string) –
The
HttpName
name of the namespace. It’s found in theHttpProperties
member of theProperties
member of the namespace.ServiceName (string) –
The name of the service that you specified when you registered the instance.
HealthStatus (string) –
If you configured health checking in the service, the current health status of the service instance.
Attributes (dict) –
If you included any attributes when you registered the instance, the values of those attributes.
(string) –
(string) –
InstancesRevision (integer) –
The increasing revision associated to the response Instances list. If a new instance is registered or deregistered, the
InstancesRevision
updates. The health status updates don’t updateInstancesRevision
.
Exceptions
ServiceDiscovery.Client.exceptions.ServiceNotFound
ServiceDiscovery.Client.exceptions.NamespaceNotFound
ServiceDiscovery.Client.exceptions.InvalidInput
ServiceDiscovery.Client.exceptions.RequestLimitExceeded
Examples
Example: Discover registered instances
response = client.discover_instances( HealthStatus='ALL', MaxResults=10, NamespaceName='example.com', ServiceName='myservice', ) print(response)
Expected Output:
{ 'Instances': [ { 'Attributes': { 'AWS_INSTANCE_IPV4': '172.2.1.3', 'AWS_INSTANCE_PORT': '808', }, 'HealthStatus': 'UNKNOWN', 'InstanceId': 'myservice-53', 'NamespaceName': 'example.com', 'ServiceName': 'myservice', }, ], 'ResponseMetadata': { '...': '...', }, }