Gsutil - How can I check if a file exists in a GCS bucket (a sub-directory) using Gsutil

Question

I have a GCS bucket containing some files in the path

gs://main-bucket/sub-directory-bucket/object1.gz

I would like to programmatically check if the sub-directory bucket contains one specific file. I would like to do this using gsutil.

How could this be done?

Solution 1

You can use the gsutil stat command.

Solution 2

Use the gsutil stat command. For accessing the sub-directories with more number of files use wildcards(*).

For example:

gsutil -q stat gs://some-bucket/some-subdir/*; echo $?

In your case:

gsutil -q stat gs://main-bucket/sub-directory-bucket/*; echo $?

Result 0 means exists; 1 means not exists

Solution 3

If your script allows for non-zero exit codes, then:

#!/bin/bash

file_path=gs://main-bucket/sub-directory-bucket/object1.gz
gsutil -q stat $file_path
status=$?

if [[ $status == 0 ]]; then
  echo "File exists"
else
  echo "File does not exist"
fi

But if your script is set to fail on error, then you can't use exit codes. Here is an alternative solution:

#!/bin/bash
trap 'exit' ERR

file_path=gs://main-bucket/sub-directory-bucket/object1.gz
result=$(gsutil -q stat $file_path || echo 1)
if [[ $result != 1 ]]; then
  echo "File exists"
else
  echo "File does not exist"
fi

Solution 4

There is also gsutil ls (https://cloud.google.com/storage/docs/gsutil/commands/ls)

e.g.

gsutil ls gs://my-bucket/foo.txt

Output is either that same filepath or "CommandException: One or more URLs matched no objects."

Solution 5

Simply using the ls command and counting the number of rows of the output.

If 0 then file not there, if 1 the file exists.

file_exists=$(gsutil ls gs://my_bucket/object1.gz | wc -l)

The same could be used for many files of course.

files_number=$(gsutil ls gs://my_bucket/object* | wc -l)

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