Tempo Coordinator K8S
| Channel | Revision | Published | Runs on |
|---|---|---|---|
| 1/stable | 79 | 16 May 2025 | |
| 1/candidate | 79 | 16 May 2025 | |
| 1/beta | 79 | 16 May 2025 | |
| 1/edge | 79 | 08 May 2025 | |
| 2/edge | 116 | 11 Sep 2025 |
juju deploy tempo-coordinator-k8s --channel 1/stable
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Platform:
charms.tempo_coordinator_k8s.v0.tempo_api
-
- Last updated 25 Aug 2025
- Revision Library version 0.4
tempo_api.
This library implements endpoint wrappers for the tempo-api interface. The tempo-api interface is used to transfer information about an instance of Tempo, such as how to access and uniquely identify it. Typically, this is useful for charms that operate a Tempo instance to give other applications access to Tempo's HTTP API.
Usage
Requirer
TempoApiRequirer is a wrapper for pulling data from the tempo-api interface. To use it in your charm:
- observe the relation-changed event for this relation wherever your charm needs to use this data (this endpoint wrapper DOES NOT automatically observe any events)
- wherever you need access to the data, call
TempoApiRequirer(...).get_data()
An example implementation is:
class FooCharm(CharmBase):
def __init__(self, framework):
super().__init__(framework)
tempo_api = TempoApiRequirer(self.model.relations, "tempo-api")
self.framework.observe(
self.on["tempo-api"].relation_changed, self._on_tempo_api_changed
)
def do_something_with_metadata(self):
data = tempo_api.get_data()
...
Where you also add relation to your charmcraft.yaml or metadata.yaml (note that TempoApiRequirer is designed for
relating to a single application and must be used with limit=1 as shown below):
requires:
tempo-api:
limit: 1
interface: tempo_api
Provider
TempoApiProvider is a wrapper for publishing data to charms related using the tempo-api interface. Note that
TempoApiProvider does not manage any events, but instead provides a publish method for sending data to
all related applications. Triggering publish appropriately is left to the charm author, although generally you want
to do this at least during the relation_joined and leader_elected events. An example implementation is:
class FooCharm(CharmBase):
def __init__(self, framework):
super().__init__(framework)
self.tempo_api = TempoApiProvider(
relations=self.model.relations,
relation_name="tempo-api",
app=self.app,
)
self.framework.observe(self.on.leader_elected, self.do_something_to_publish)
self.framework.observe(
self._charm.on["tempo-api"].relation_joined, self.do_something_to_publish
)
self.framework.observe(
self.on.some_event_that_changes_tempos_url, self.do_something_to_publish
)
def do_something_to_publish(self, e):
self.tempo_api.publish(...)
Where you also add the following to your charmcraft.yaml or metadata.yaml:
provides:
tempo-api:
interface: tempo_api
Index
class TempoApiUrls
Description
Data model for urls Tempo offers for query access, for a given protocol. None
class TempoApiAppData
Description
Data model for the tempo-api interface. None
class TempoApiRequirer
Description
Endpoint wrapper for the requirer side of the tempo-api relation. None
Methods
TempoApiRequirer. __init__( self , relation_mapping: RelationMapping , relation_name: str )
Initialize the TempoApiRequirer object.
Arguments
The RelationMapping of a charm (typically self.model.relations from within a charm
object).
The name of the wrapped relation.
Description
This object is for accessing data from relations that use the tempo-api interface. It does not autonomously handle the events associated with that relation. It is up to the charm using this object to observe those events as they see fit. Typically, that charm should observe this relation's relation-changed event.
This object requires the relation has limit=1 set in charmcraft.yaml, otherwise it will raise a ValueError exception.
TempoApiRequirer. relations( self )
Description
Return the relation instances for applications related to us on the monitored relation. None
TempoApiRequirer. get_data( self )
Return data from the relation.
Description
Returns None if no data is available, either because no applications are related to us, or because the related application has not sent data. To distinguish between these cases, check if len(tempo_api_requirer.relations)==0.
class TempoApiProvider
Description
The provider side of the tempo-api relation. None
Methods
TempoApiProvider. __init__( self , relation_mapping: RelationMapping , relation_name: str , app: Application )
Initialize the TempoApiProvider object.
Arguments
The RelationMapping of a charm (typically self.model.relations from within a charm
object).
This application.
The name of the wrapped relation.
Description
This object is for serializing and sending data to a relation that uses the tempo-api interface - it does not automatically observe any events for that relation. It is up to the charm using this to call publish when it is appropriate to do so, typically on at least the charm's leader_elected event and this relation's relation_joined event.
TempoApiProvider. relations( self )
Description
Return the applications related to us under the monitored relation. None
TempoApiProvider. publish( self , direct_url_http , direct_url_grpc , ingress_url_http , ingress_url_grpc )
Post tempo-api to all related applications.
Arguments
The cluster-internal URL at which this application can be reached for an http connection. Typically, this is a Kubernetes FQDN like name.namespace.svc.cluster.local for connecting to the tempo http api from inside the cluster, with scheme and maybe port.
The cluster-internal URL at which this application can be reached for a grpc connection. Typically, this is a Kubernetes FQDN like name.namespace.svc.cluster.local for connecting to the tempo grpc api from inside the cluster, with scheme.
The non-internal URL at which this application can be reached for an http connection. Typically, this is an ingress URL.
The non-internal URL at which this application can be reached for a grpc connection. Typically, this is an ingress URL.
Description
This method writes to the relation's app data bag, and thus should never be called by a unit that is not the leader otherwise ops will raise an exception.