Accessing File Systems from Running Functions

A function you've deployed to Oracle Functions can access the file system of the container in which it's running as follows:

  • the function can read files from all directories
  • the function can write files to the /tmp directory

For example, you might want a function to download an Excel file and then read its contents. To meet this requirement, you might create a function that writes the file to the /tmp directory in the container's filesystem, and then subsequently reads the file.

When writing files to the /tmp directory, the /tmp directory is generally always writable. However, the maximum allowable size of the /tmp directory depends on the maximum memory threshold specified for the function:

Maximum memory threshold for the function (MB) Maximum allowed size of /tmp (MB) Maximum allowed number of files (inodes) in /tmp
128MB 32MB 1024
256MB 64MB 2048
512MB 128MB 4096
1024MB 256MB 8192

Note that the /tmp directory might be shared by multiple invocations of the function. A file written by an earlier invocation of a function could still exist when the function is invoked a second time. It is your responsibility to delete any files to avoid unexpected behavior.