Import and export data

Export data or import data with W&B Public APIs.

Import data from MLFlow

W&B supports importing data from MLFlow, including experiments, runs, artifacts, metrics, and other metadata.

Install dependencies:

# note: this requires py38+
pip install wandb[importers]

Log in to W&B. Follow the prompts if you have not logged in before.

wandb login

Import all runs from an existing MLFlow server:

from wandb.apis.importers.mlflow import MlflowImporter

importer = MlflowImporter(mlflow_tracking_uri="...")

runs = importer.collect_runs()
importer.import_runs(runs)

By default, importer.collect_runs() collects all runs from the MLFlow server. If you prefer to upload a special subset, you can construct your own runs iterable and pass it to the importer.

import mlflow
from wandb.apis.importers.mlflow import MlflowRun

client = mlflow.tracking.MlflowClient(mlflow_tracking_uri)

runs: Iterable[MlflowRun] = []
for run in mlflow_client.search_runs(...):
    runs.append(MlflowRun(run, client))

importer.import_runs(runs)

To skip importing artifacts, you can pass artifacts=False:

importer.import_runs(runs, artifacts=False)

To import to a specific W&B entity and project, you can pass a Namespace:

from wandb.apis.importers import Namespace

importer.import_runs(runs, namespace=Namespace(entity, project))

Export Data

Use the Public API to export or update data that you have saved to W&B. Before using this API, log data from your script. Check the Quickstart for more details.

Use Cases for the Public API

• Export Data: Pull down a dataframe for custom analysis in a Jupyter Notebook. Once you have explored the data, you can sync your findings by creating a new analysis run and logging results, for example: wandb.init(job_type="analysis")
• Update Existing Runs: You can update the data logged in association with a W&B run. For example, you might want to update the config of a set of runs to include additional information, like the architecture or a hyperparameter that wasn’t originally logged.

See the Generated Reference Docs for details on available functions.

Create an API key

An API key authenticates your machine to W&B. You can generate an API key from your user profile.

1. Click your user profile icon in the upper right corner.
2. Select User Settings, then scroll to the API Keys section.
3. Click Reveal. Copy the displayed API key. To hide the API key, reload the page.

Find the run path

To use the Public API, you’ll often need the run path which is <entity>/<project>/<run_id>. In the app UI, open a run page and click the Overview tab to get the run path.

Export Run Data

Download data from a finished or active run. Common usage includes downloading a dataframe for custom analysis in a Jupyter notebook, or using custom logic in an automated environment.

import wandb

api = wandb.Api()
run = api.run("<entity>/<project>/<run_id>")

The most commonly used attributes of a run object are:

You can also modify or update the data of past runs. By default a single instance of an api object will cache all network requests. If your use case requires real time information in a running script, call api.flush() to get updated values.

Understanding the Different Attributes

For the below run

n_epochs = 5
config = {"n_epochs": n_epochs}
run = wandb.init(project=project, config=config)
for n in range(run.config.get("n_epochs")):
    run.log(
        {"val": random.randint(0, 1000), "loss": (random.randint(0, 1000) / 1000.00)}
    )
run.finish()

these are the different outputs for the above run object attributes

run.config

{"n_epochs": 5}

run.summary

{
    "_runtime": 4,
    "_step": 4,
    "_timestamp": 1644345412,
    "_wandb": {"runtime": 3},
    "loss": 0.041,
    "val": 525,
}

Sampling

The default history method samples the metrics to a fixed number of samples (the default is 500, you can change this with the samples __ argument). If you want to export all of the data on a large run, you can use the run.scan_history() method. For more details see the API Reference.

Querying Multiple Runs

• DataFrame and CSVs
• MongoDB Style

import pandas as pd
import wandb

api = wandb.Api()
entity, project = "<entity>", "<project>"
runs = api.runs(entity + "/" + project)

summary_list, config_list, name_list = [], [], []
for run in runs:
    # .summary contains output keys/values for
    # metrics such as accuracy.
    #  We call ._json_dict to omit large files
    summary_list.append(run.summary._json_dict)

    # .config contains the hyperparameters.
    #  We remove special values that start with _.
    config_list.append({k: v for k, v in run.config.items() if not k.startswith("_")})

    # .name is the human-readable name of the run.
    name_list.append(run.name)

runs_df = pd.DataFrame(
    {"summary": summary_list, "config": config_list, "name": name_list}
)

runs_df.to_csv("project.csv")

runs = api.runs(
    "username/project",
    {"$or": [{"config.experiment_name": "foo"}, {"config.experiment_name": "bar"}]},
)
print(f"Found {len(runs)} runs")

Calling api.runs returns a Runs object that is iterable and acts like a list. By default the object loads 50 runs at a time in sequence as required, but you can change the number loaded per page with the per_page keyword argument.

api.runs also accepts an order keyword argument. The default order is -created_at. To order results ascending, specify +created_at. You can also sort by config or summary values. For example, summary.val_acc or config.experiment_name.

Error Handling

If errors occur while talking to W&B servers a wandb.CommError will be raised. The original exception can be introspected via the exc attribute.

Get the latest git commit through the API

In the UI, click on a run and then click the Overview tab on the run page to see the latest git commit. It’s also in the file wandb-metadata.json . Using the public API, you can get the git hash with run.commit.

Get a run’s name and ID during a run

After calling wandb.init() you can access the random run ID or the human readable run name from your script like this:

• Unique run ID (8 character hash): wandb.run.id
• Random run name (human readable): wandb.run.name

If you’re thinking about ways to set useful identifiers for your runs, here’s what we recommend:

• Run ID: leave it as the generated hash. This needs to be unique across runs in your project.
• Run name: This should be something short, readable, and preferably unique so that you can tell the difference between different lines on your charts.
• Run notes: This is a great place to put a quick description of what you’re doing in your run. You can set this with wandb.init(notes="your notes here")
• Run tags: Track things dynamically in run tags, and use filters in the UI to filter your table down to just the runs you care about. You can set tags from your script and then edit them in the UI, both in the runs table and the overview tab of the run page. See the detailed instructions here.

Public API Examples

Export data to visualize in matplotlib or seaborn

Check out our API examples for some common export patterns. You can also click the download button on a custom plot or on the expanded runs table to download a CSV from your browser.

Read metrics from a run

This example outputs timestamp and accuracy saved with wandb.log({"accuracy": acc}) for a run saved to "<entity>/<project>/<run_id>".

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
if run.state == "finished":
    for i, row in run.history().iterrows():
        print(row["_timestamp"], row["accuracy"])

Filter runs

You can filters by using the MongoDB Query Language.

Date

runs = api.runs(
    "<entity>/<project>",
    {"$and": [{"created_at": {"$lt": "YYYY-MM-DDT##", "$gt": "YYYY-MM-DDT##"}}]},
)

Read specific metrics from a run

To pull specific metrics from a run, use the keys argument. The default number of samples when using run.history() is 500. Logged steps that do not include a specific metric will appear in the output dataframe as NaN. The keys argument will cause the API to sample steps that include the listed metric keys more frequently.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
if run.state == "finished":
    for i, row in run.history(keys=["accuracy"]).iterrows():
        print(row["_timestamp"], row["accuracy"])

Compare two runs

This will output the config parameters that are different between run1 and run2.

import pandas as pd
import wandb

api = wandb.Api()

# replace with your <entity>, <project>, and <run_id>
run1 = api.run("<entity>/<project>/<run_id>")
run2 = api.run("<entity>/<project>/<run_id>")


df = pd.DataFrame([run1.config, run2.config]).transpose()

df.columns = [run1.name, run2.name]
print(df[df[run1.name] != df[run2.name]])

Outputs:

              c_10_sgd_0.025_0.01_long_switch base_adam_4_conv_2fc
batch_size                                 32                   16
n_conv_layers                               5                    4
optimizer                             rmsprop                 adam

Update metrics for a run, after the run has finished

This example sets the accuracy of a previous run to 0.9. It also modifies the accuracy histogram of a previous run to be the histogram of numpy_array.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
run.summary["accuracy"] = 0.9
run.summary["accuracy_histogram"] = wandb.Histogram(numpy_array)
run.summary.update()

Rename a metric in a completed run

This example renames a summary column in your tables.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
run.summary["new_name"] = run.summary["old_name"]
del run.summary["old_name"]
run.summary.update()

Update config for an existing run

This examples updates one of your configuration settings.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
run.config["key"] = updated_value
run.update()

Export system resource consumptions to a CSV file

The snippet below would find the system resource consumptions and then, save them to a CSV.

import wandb

run = wandb.Api().run("<entity>/<project>/<run_id>")

system_metrics = run.history(stream="events")
system_metrics.to_csv("sys_metrics.csv")

Get unsampled metric data

When you pull data from history, by default it’s sampled to 500 points. Get all the logged data points using run.scan_history(). Here’s an example downloading all the loss data points logged in history.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
history = run.scan_history()
losses = [row["loss"] for row in history]

Get paginated data from history

If metrics are being fetched slowly on our backend or API requests are timing out, you can try lowering the page size in scan_history so that individual requests don’t time out. The default page size is 500, so you can experiment with different sizes to see what works best:

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
run.scan_history(keys=sorted(cols), page_size=100)

Export metrics from all runs in a project to a CSV file

This script pulls down the runs in a project and produces a dataframe and a CSV of runs including their names, configs, and summary stats. Replace <entity> and <project> with your W&B entity and the name of your project, respectively.

import pandas as pd
import wandb

api = wandb.Api()
entity, project = "<entity>", "<project>"
runs = api.runs(entity + "/" + project)

summary_list, config_list, name_list = [], [], []
for run in runs:
    # .summary contains the output keys/values
    #  for metrics such as accuracy.
    #  We call ._json_dict to omit large files
    summary_list.append(run.summary._json_dict)

    # .config contains the hyperparameters.
    #  We remove special values that start with _.
    config_list.append({k: v for k, v in run.config.items() if not k.startswith("_")})

    # .name is the human-readable name of the run.
    name_list.append(run.name)

runs_df = pd.DataFrame(
    {"summary": summary_list, "config": config_list, "name": name_list}
)

runs_df.to_csv("project.csv")

Get the starting time for a run

This code snippet retrieves the time at which the run was created.

import wandb

api = wandb.Api()

run = api.run("entity/project/run_id")
start_time = run.created_at

Upload files to a finished run

The code snippet below uploads a selected file to a finished run.

import wandb

api = wandb.Api()

run = api.run("entity/project/run_id")
run.upload_file("file_name.extension")

Download a file from a run

This finds the file “model-best.h5” associated with run ID uxte44z7 in the cifar project and saves it locally.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
run.file("model-best.h5").download()

Download all files from a run

This finds all files associated with a run and saves them locally.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
for file in run.files():
    file.download()

Get runs from a specific sweep

This snippet downloads all the runs associated with a particular sweep.

import wandb

api = wandb.Api()

sweep = api.sweep("<entity>/<project>/<sweep_id>")
sweep_runs = sweep.runs

Get the best run from a sweep

The following snippet gets the best run from a given sweep.

import wandb

api = wandb.Api()

sweep = api.sweep("<entity>/<project>/<sweep_id>")
best_run = sweep.best_run()

The best_run is the run with the best metric as defined by the metric parameter in the sweep config.

Download the best model file from a sweep

This snippet downloads the model file with the highest validation accuracy from a sweep with runs that saved model files to model.h5.

import wandb

api = wandb.Api()

sweep = api.sweep("<entity>/<project>/<sweep_id>")
runs = sorted(sweep.runs, key=lambda run: run.summary.get("val_acc", 0), reverse=True)
val_acc = runs[0].summary.get("val_acc", 0)
print(f"Best run {runs[0].name} with {val_acc}% val accuracy")

runs[0].file("model.h5").download(replace=True)
print("Best model saved to model-best.h5")

Delete all files with a given extension from a run

This snippet deletes files with a given extension from a run.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")

extension = ".png"
files = run.files()
for file in files:
    if file.name.endswith(extension):
        file.delete()

Download system metrics data

This snippet produces a dataframe with all the system resource consumption metrics for a run and then saves it to a CSV.

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")
system_metrics = run.history(stream="events")
system_metrics.to_csv("sys_metrics.csv")

Update summary metrics

You can pass a dictionary to update summary metrics.

summary.update({"key": val})

Get the command that ran the run

Each run captures the command that launched it on the run overview page. To pull this command down from the API, you can run:

import wandb

api = wandb.Api()

run = api.run("<entity>/<project>/<run_id>")

meta = json.load(run.file("wandb-metadata.json").download())
program = ["python"] + [meta["program"]] + meta["args"]