Playing around with the LakeFS API using the Java client, I started by running the sample on Getting Started, but I'm having some issues

Expected URL scheme 'http' or 'https' but no scheme was found for /api/v...

I think this connects to the right path but did not specify the host:

defaultClient.setBasePath("/api/v1")

with http://localhost:8000/api/v1 I get this error instead

Exception when calling ActionsApi#getRun

Status code: 404

Reason: {"message":"not found: not found"}

Response headers: {content-length=[35], content-type=[application/json], date=[Wed, 14 Feb 2024 125320 GMT], x-content-type-options=[nosniff], x-request-id=[79c62be2-5501-484d-b901-c4d0e9d4b690]}

io.lakefs.clients.sdk.ApiException: Message: Not Found

HTTP response code: 404

HTTP response body: {"message":"not found: not found"}

HTTP response headers: {content-length=[35], content-type=[application/json], date=[Wed, 14 Feb 2024 125320 GMT], x-content-type-options=[nosniff], x-request-id=[79c62be2-5501-484d-b901-c4d0e9d4b690]}

at io.lakefs.clients.sdk.ApiClient.handleResponse(ApiClient.java:1138)

at io.lakefs.clients.sdk.ApiClient.execute(ApiClient.java:1051)

at io.lakefs.clients.sdk.ActionsApi.getRunWithHttpInfo(ActionsApi.java:145)

at io.lakefs.clients.sdk.ActionsApi.access$100(ActionsApi.java:42)

at io.lakefs.clients.sdk.ActionsApi$APIgetRunRequest.execute(ActionsApi.java:199)

at com.example.ApplicationKt$configureRouting$1$1.invokeSuspend(Application.kt:77)

at com.example.ApplicationKt$configureRouting$1$1.invoke(Application.kt)

Hi Giuseppe, I'd start by reading the OpenAPI spec to understand what 404 means. I'd bet here that the run id does not exist.

what is the

runId

?

It will probably be easier to track the API after reading about actions and hooks. Run IDs are opaque, you can get them from lakeFS by doing things like listing, by API or lakectl or web-UI.

Actually, I'm not even sure I need to execute

apiInstance::getRun

, I was just eager to get anything running I'd be more than happy if I can get somehow this on the Java client

for change in client.diff(repo, from_ref, target_branch, prefix=prefix):

ApiClient

seems to have no

diff

or similar method available

1. You're definitely talking to your lakeFS. 2. The best guide for exploring our OpenAPI is the lakeFS API Reference. It is generated from swagger.yml, which is the definitive reference. You can search either one for "diff" to find diffBranch (difference between a branch and its staging area, aka uncommitted changes) and diffRefs (difference between two lakeFS refs). HTH.

sorry, but I still fail to grasp this in the LakeFS API Reference you linked, I found, for example, this

GET /repositories/{repository}/branches/{branch}/diff diff branch

Do you mean I shall manually create an Http GET to get the info I'd like to have?

That's the OpenAPI visualizer, which indeed primarily shows the REST API. Personally I usually prefer just to read the spec and use the generated SDK. If you go to the spec, that call is called diffBranch, and the generated JVM client uses that name. We committed as part of 1.0 to supply the REST API as an OpenAPI spec, and we additionally generate and publish clients for Python and the JVM.

at the end I could see the staging files with

val api = BranchesApi(defaultClient)
val diffList = api.diffBranch(schema.repositoryId, schema.branchId).execute()

where

schema

is the parsed class from the received text (I'm posting for others looking at the same problem)

Sure. There are actually no issues with multithreading or atomicity. For reading and writing in Python we recommend the higher level SDK. It makes things easier. lakeFSFS is a great solution for Hadoop-based work, for insurance in Spark. I would not recommend introducing Hadoop anywhere you don't need it.

yes, I saw that, but I'm looking for reading in the jvm world

We have currently have nothing similar for the Java world. Of course, with significant demand this may change.

looks like it's even simpler than that

val objectsApi = ObjectsApi(defaultClient)
    val objectStatsList = objectsApi.listObjects("quickstart", "main").execute()
    println(objectStatsList)
    val readme = objectStatsList.results.first { it.path == "README.md" }
    val readme2 = objectsApi.getObject("quickstart", "main", "README.md").execute()
    println(Path(readme.physicalAddress.substringAfter("local://")).readText())
    println(readme2.readText())

It has nothing to do with the quickstart. It should work the same way regardless of the repository and/or block store type. So, yes, it should work the same way with MinIO.

I see

InternalApi(defaultClient).lakeFSVersion

is marked as deprecate, what shall it be substituted with? Everything I can find still points to

InternalApi

It is an internal API, used by the GUI. Typical user programs should have little use for this API. Even the format of the reply strings might not be what you expect. "Internal" means that it is not subject to the lakFS compatibility guarantees. You may of course call whatever API you want, just please be mindful of the guarantees that we can provide.

I'm working with the client java api for our internal researchers and on the side, I'm trying to develop some sort of high level wrapper, counterpart of the python one already existing

The source of truth is the OpenAPI spec that I have linked. Cross-language specs cannot assume the same annotations across all languages, and indeed even in a single language or even platform such as the JVM there is no point in adding an annotation not supported by the toolchain.