Advanced usage

Environment variables

Several environment variables can be passed to Gokapi. They can be used to modify settings that are not present during setup or to pass cloud storage credentials without saving them to the filesystem.

Passing environment variables to Gokapi

Docker

Pass the variable with the -e argument. Example for setting the port in use to 12345 and the database filename to database.sqlite:

docker run -it -e GOKAPI_PORT=12345 -e GOKAPI_DB_NAME=database.sqlite f0rc3/gokapi:latest

Native Deployment

Linux / Unix

For Linux / Unix environments, execute the binary in this format:

GOKAPI_PORT=12345 GOKAPI_DB_NAME=database.sqlite [...] ./Gokapi

Windows

For Windows environments, you need to run setx first, e.g.:

setx GOKAPI_PORT 12345
setx GOKAPI_DB_NAME database.sqlite
[...]
Gokapi.exe

Available environment variables

Name	Action	Persistent [*]	Default
GOKAPI_CHUNK_SIZE_MB	Sets the size of chunks that are uploaded in MB	Yes	45
GOKAPI_CONFIG_DIR	Sets the directory for the config file	No	config
GOKAPI_CONFIG_FILE	Sets the name of the config file	No	config.json
GOKAPI_DATA_DIR	Sets the directory for the data	Yes	data
GOKAPI_DATABASE_URL	Sets the type and location of the database. See Databases	Yes	sqlite://[data folder]/gokapi.sqlite
GOKAPI_LENGTH_ID	Sets the length of the download IDs. Value needs to be 5 or more	Yes	15
GOKAPI_MAX_FILESIZE	Sets the maximum allowed file size in MB	Yes	102400 (100GB)
GOKAPI_MAX_MEMORY_UPLOAD	Sets the amount of RAM in MB that can be allocated for an upload chunk or file Any chunk or file with a size greater than that will be written to a temporary file	Yes	50
GOKAPI_MAX_PARALLEL_UPLOADS	Set the amount of chunks that are uploaded in parallel for a single file	Yes	4
GOKAPI_PORT	Sets the webserver port	Yes	53842
GOKAPI_DISABLE_CORS_CHECK	Disables the CORS check on startup and during setup, if set to “true”	No	false
GOKAPI_LOG_STDOUT	Also outputs all log file entries to the console output	No	false
DOCKER_NONROOT	Docker only: Runs the binary in the container as a non-root user, if set to “true”	No	false
TMPDIR	Sets the path which contains temporary files	No	Non-Docker: Default OS path Docker: [DATA_DIR]
GOKAPI_DB_NAME (deprecated)	Sets the name for the database file. Deprecated: Only used during update. Will be removed with v1.10.0	No	gokapi.sqlite

[*]

Variables that are persistent must be submitted during the first start when Gokapi creates a new config file. They can be omitted afterwards. Non-persistent variables need to be set on every start.

All values that are described in Cloudstorage can be passed as environment variables as well. No values are persistent; therefore, they need to be set on every start.

Name	Action	Example
GOKAPI_AWS_BUCKET	Sets the bucket name	gokapi
GOKAPI_AWS_REGION	Sets the region name	eu-central-000
GOKAPI_AWS_KEY	Sets the API key	123456789
GOKAPI_AWS_KEY_SECRET	Sets the API key secret	abcdefg123
GOKAPI_AWS_ENDPOINT	Sets the endpoint	eu-central-000.provider.com
GOKAPI_AWS_PROXY_DOWNLOAD	If true, users will not be redirected to a pre-signed S3 URL for downloading. Instead, Gokapi will download the file and proxy it to the user	true (default:false)

Databases

By default, Gokapi uses an SQLite database for data storage, which should suffice for most use cases. Additionally, Redis is available as an experimental option.

Migrating to a different database

To switch to a different database, Gokapi provides a migration tool. By running:

gokapi --migrate [old Database URL] [new Database URL]

all existing data, except for user sessions, will be transferred to the new database. After the migration, you will need to rerun the setup and specify the new database location. For details on the correct database URL format, refer to the section Database URL format.

For Docker users, the command is:

docker run --rm -v gokapi-data:/app/data f0rc3/gokapi:latest /app/run.sh [old Database URL] [new Database URL]

Database URL format

Database URLs must start with either sqlite:// or redis://.

For SQLite, the path to the database follows the prefix. No additional options are allowed.

For Redis, the URL can include authentication credentials (username and password), an optional prefix for keys, and parameter to use SSL.

A Redis URL has the following structure:

redis://[username:password@]host[:port][?options]

• username: (optional) The username for authentication.

• password: (optional) The password for authentication.

• host: (required) The address of the Redis server.

• port: (optional) The port of the Redis server (default is 6379).

• options: (optional) Additional options such as SSL (ssl=true) and key prefix (prefix=).

Examples

Migrating SQLite (/app/data/gokapi.sqlite) to Redis (127.0.0.1:6379):

gokapi --migrate sqlite:///app/data/gokapi.sqlite redis://127.0.0.1:6379

Migrating SQLite (/app/data/gokapi.sqlite) to SQLite (./data/gokapi.sqlite):

gokapi --migrate sqlite:///app/data/gokapi.sqlite sqlite://./data/gokapi.sqlite

Migrating Redis (127.0.0.1:6379, User: test, Password: 1234, Prefix: gokapi_, using SSL) to SQLite (./data/gokapi.sqlite):

gokapi --migrate "redis://test:1234@127.0.0.1:6379?prefix=gokapi_&ssl=true" sqlite://./data/gokapi.sqlite

API

Gokapi offers an API that can be reached at http(s)://your.gokapi.url/api/. You can find the current documentation with an overview of all API functions and examples at http(s)://your.gokapi.url/apidocumentation/.

Interacting with the API

All API calls will need an API key as authentication. An API key can be generated in the web UI in the menu “API”. The API key needs to be passed as a header.

Example: Getting a list of all stored files with curl

curl -X GET "https://your.gokapi.url/api/files/list" -H "accept: application/json" -H "apikey: secret"

Some calls expect parameters as form/post parameter, others as headers. Please refer to the current API documentation.

Example: Uploading a file

curl -X POST "https://your.gokapi.url/api/files/add" -H "accept: application/json" -H "apikey: secret" -H "Content-Type: multipart/form-data" -F "allowedDownloads=1" -F "expiryDays=5" -F "password=" -F "file=@yourfile.dat"

Example: Deleting a file

curl -X DELETE "https://your.gokapi.url/api/files/delete" -H "accept: */*" -H "id: PFnh2DlQRS2PVKM" -H "apikey: secret"

Chunk Sizes / Considerations for servers with limited or high amount of RAM

By default, Gokapi uploads files in 45MB chunks stored in RAM. Up to 4 chunks are sent in parallel to enhance upload speed, requiring up to 200MB of RAM per file during upload in the standard configuration.

Servers with limited RAM

To conserve RAM, you can either

• configure Gokapi to save the chunks on disk instead of RAM, by setting the MaxMemory setting to a value lower than your chunk size

• reduce the chunk size by setting the ChunkSize to a lower value

• decrease the amount of parallel uploads by setting MaxParallelUploads to a lower value

Refer to Changing the configuration for instructions on changing these values.

Servers with high amount of RAM

If your server has a lot of available RAM, you can improve upload speed by increasing the chunk size, which reduces overhead during upload.

• Increase the chunk size by setting the ChunkSize to a larger value

• Make sure that the MaxMemory setting is a higher value than your chunk size

• Consider increasing the amount of parallel uploads by setting MaxParallelUploads to a higher value

Refer to Changing the configuration for instructions on changing these values.

Note

Ensure your reverse proxy and CDN (if applicable) support the chosen chunk size. Cloudflare users on the free tier are limited to 100MB file chunks.

Changing the configuration

If you have not completed the Gokapi setup yet, you can set all the values mentioned above using environment variables. See Passing environment variables to Gokapi for instructions. If the setup is complete, Gokapi will ignore these environment variables, and you’ll need to modify the configuration file (by default: config.json in the folder config). See the table below on how to change the values:

Configuration	Environment Variable	Configuration File Entry	Default
Chunk size for uploads	GOKAPI_CHUNK_SIZE_MB	ChunkSize	45
Maximum size for chunks or whole files to store in RAM during upload	GOKAPI_MAX_MEMORY_UPLOAD	MaxMemory	50
Parallel uploads per file	GOKAPI_MAX_PARALLEL_UPLOADS	MaxParallelUploads	4

Automatic Deployment

It is possible to deploy Gokapi without having to run the setup. You will need to complete the setup on a temporary instance first. This is to create the configuration files, which can then be used for deployment.

Configuration Files

The configuration consists of up to two files in the configuration directory (default: config). All files can be read-only, however config.json might need write access in some situations.

cloudconfig.yml

Stores the access data for cloud storage. This can be reused without modification, however all fields can also be set with environment variables. The file does not exist if no cloud storage is used and can always be read-only.

config.json

Contains the server configuration. If you want to deploy Gokapi in multiple instances for redundancy (e.g. all instances share the same data), then the configuration file can be reused without modification. Otherwise you need to modify it before deploying (see below). Can be read-only, but might need write access when upgrading Gokapi to a newer version. Needs write access when re-running setup or changing the admin password.

Modifying config.json to deploy without setup

If you want to deploy Gokapi to multiple instances that contain different data, you have to modify the config.json. Open it and change the following fields:

Field	Operation	Example
SaltAdmin	Change to empty value	“SaltAdmin”: “”,
SaltFiles	Change to empty value	“SaltFiles”: “”,
Password	Change to empty value	“Password”: “”,
Username	Change to the username of your preference, if you are using internal username/password authentication	“Username”: “admin”,

Setting an admin password

If you are using internal username/password authentication, run the binary with the parameter --deployment-password [YOUR_PASSWORD]. This sets the password and also generates a new salt for the password. This has to be done before Gokapi is run for the first time on the new instance. Alternatively you can do this on the orchestrating machine and then copy the configuration file to the new instance.

If you are using a Docker image, this has to be done by starting a container with the entrypoint /app/run.sh, for example:

docker run --rm -v gokapi-data:/app/data -v gokapi-config:/app/config  f0rc3/gokapi:latest /app/run.sh --deployment-password newPassword

Customising

By default, all files are included in the executable. If you want to change the layout (e.g. add your company logo or change the app name etc.), follow these steps:

1. Download the source code for the Gokapi version you are using. It is either attached to the specific release on Github or you can clone the repository and checkout the tag for the specific version.

2. Copy either the folder static, templates or both from the internal/webserver/web folder to the directory where the executable is located (if you are using Docker, mount the folders into the the /app/ directory, e.g. /app/templates).

3. Make changes to the folders. static contains images, CSS files and JavaScript. templates contains the HTML code.

4. Restart the server. If the folders exist, the server will use the local files instead of the embedded files.

5. Optional: To embed the files permanently, copy the modified files back to the original folders and recompile with go generate ./... and then go build github.com/forceu/gokapi/cmd/gokapi.