SPDX-License-Identifier: CC-BY-SA-3.0
{% endcomment %}
+{% comment %}
+A note about scope for future authors: This page is meant to be a general guide to using the API client. It is intentionally limited to using the general resource methods as examples, because those are widely available and should be sufficient to give the reader a general understanding of how the API client works. In my opinion we should not cover resource-specific API methods here, and instead prefer to cover them in the cookbook or reference documentation, which have a more appropriate scope. --Brett 2022-12-06
+{% endcomment %}
The Arvados Python SDK provides a complete client interface to the "Arvados API":{{site.baseurl}}/api/index.html. You can use this client interface directly to send requests to your Arvados API server, and many of the higher-level interfaces in the Python SDK accept a client object in their constructor for their use. Any Arvados software you write in Python will likely use these client objects.
Each resource object has a method that corresponds to each API method supported by that resource type. You call these methods with the keyword arguments and values documented in the API reference. They return an API request object.
-Each API request object has an @execute()@ method. You may pass a @num_retries@ integer argument to retry the operation that many times, with exponential back-off, in case of temporary errors like network problems. If it ultimately succeeds, it returns the kind of object documented in the API reference for that method. Usually that's a dictionary with details about the object you requested. If there's a problem, it raises an exception.
+Each API request object has an @execute()@ method. If it succeeds, it returns the kind of object documented in the API reference for that method. Usually that's a dictionary with details about the object you requested. If there's a problem, it raises an exception.
Putting it all together, basic API requests usually look like:
arv_object = arv_client.resource_type().api_method(
argument=...,
other_argument=...,
-).execute(num_retries=3)
+).execute()
{% endcodeblock %}
-The following sections detail how to call "common resource methods in the API":{{site.baseurl}}/api/methods.html with more concrete examples. Additional methods may be available on specific resource types.
+Later sections detail how to call "common resource methods in the API":{{site.baseurl}}/api/methods.html with more concrete examples. Additional methods may be available on specific resource types.
+
+h3. Retrying failed requests
+
+If you execute an API request and it fails because of a temporary error like a network problem, the SDK waits with randomized exponential back-off, then retries the request. You can specify the maximum number of retries by passing a @num_retries@ integer to either @arvados.api@ or the @execute()@ method; the SDK will use whichever number is greater. The default number of retries is 10, which means that an API request could take up to about 35 minutes if the temporary problem persists that long. To disable automatic retries, just pass @num_retries=0@ to @arvados.api@:
+
+{% codeblock as python %}
+import arvados
+arv_client = arvados.api('v1', num_retries=0, ...)
+{% endcodeblock %}
h2. get method
print(f"{container['uuid']}: {container['exit_code']}")
{% endcodeblock %}
-If you need to retrieve all of the results for a list, you need to call the list method multiple times with the same search criteria and increasing @offset@ arguments until no more items are returned. The SDK function @arvados.util.keyset_list_all@ can orchestrate this for you. Call it with the @list@ method you want to query (don't call it yourself!) and the same keyword arguments you would pass to that method. You can control ordering by passing an @order_key@ string that names the field to use, and an @ascending@ bool that indicates whether that key should be sorted in ascending or descending order.
+If you need to retrieve all of the results for a query, you may need to call the @list@ method multiple times: the default @limit@ is 100 items, and the API server will never return more than 1000. The SDK function @arvados.util.keyset_list_all@ can help orchestrate this for you. Call it with the @list@ method you want to query (don't call it yourself!) and the same keyword arguments you would pass to that method. You can control ordering by passing an @order_key@ string that names the field to use, and an @ascending@ bool that indicates whether that key should be sorted in ascending or descending order. The function returns an iterator of dictionaries, where each dictionary corresponds to an Arvados object that matched your query.
{% codeblock as python %}
# Output all the portable data hashes in a project.
h2. update method
-To modify an existing Arvados object, call the @update@ method for that resource type. You must pass a @uuid@ string argument that identifies the object to update, and a @body@ dictionary @body@ with a single item. Its key is the resource type you're creating as a string, and its value is dictionary of data fields to update on the resource. The method returns a dictionary with the updated object's fields.
+To modify an existing Arvados object, call the @update@ method for that resource type. You must pass a @uuid@ string argument that identifies the object to update, and a @body@ dictionary with a single item. Its key is the resource type you're creating as a string, and its value is dictionary of data fields to update on the resource. The method returns a dictionary with the updated object's fields.
If the resource type has a @name@ field, you may pass an @ensure_unique_name@ boolean argument. If true, the method will automatically update the name of the new object to make it unique if necessary.
projects / arvados.git / blobdiff