Gotenberg
A stateless API for converting Markdown files, HTML files and Office documents to PDF
---
At TheCodingMachine, we build a lot of web applications (intranets, extranets and so on) which require to generate PDF from
various sources. Each time, we ended up using some well known libraries like **wkhtmltopdf** or **unoconv** and kind of lost time by
reimplementing a solution from a project to another project. Meh.
# Menu
* [Usage](#usage)
* [Security](#security)
* [Scalability](#scalability)
* [Custom implementation](#custom-implementation)
* [Clients](#clients)
## Usage
Let's say you're starting the API using this simple command:
```sh
$ docker run --rm -p 3000:3000 thecodingmachine/gotenberg:2.0.0
```
The API is now available on your host under `http://127.0.0.1:3000`.
It accepts `POST` requests with a `multipart/form-data` Content-Type. Your form data should provide one or more files to convert.
The default image accepts the following:
* Markdown files
* HTML files
* Office documents (.docx, .doc, .odt, .pptx, .ppt, .odp and so on)
* PDF files
**Heads up:** the API relies on the file extension to determine which library to use for conversion.
There are two use cases:
* If you send one file, it will convert it and return the resulting PDF
* If many files, it will convert them to PDF, merge the resulting PDFs into a single PDF and return it
### Examples:
* One file
```sh
$ curl --request POST \
--url http://127.0.0.1:3000 \
--header 'Content-Type: multipart/form-data' \
--form files=@file.docx \
> result.pdf
```
* Many files
```sh
$ curl --request POST \
--url http://127.0.0.1:3000 \
--header 'Content-Type: multipart/form-data' \
--form files=@file.md \
--form files=@file.html \
--form files=@file.pdf \
--form files=@file.docx \
> result.pdf
```
## Security
The API does not provide any authentication mechanisms. Make sure to not put it on a public facing port and your client(s) should always
controls what is sent to the API.
## Scalability
Some libraries like **unoconv** cannot perform concurrent conversions. That's why the API does only one conversion at a time.
If your API is under heavy load, a request will take time to be processed.
Fortunately, you may pass through this limitation by scaling the API.
In the following example, I'll demonstrate how to do some vertical scaling (= on the same machine) with Docker Compose, but of course horizontal scaling works too!
```yaml
version: '3'
services:
# your others services
gotenberg:
image: thecodingmachine/gotenberg:2.0.0
```
You may now launch your services using:
```bash
docker-compose up --scale gotenberg=your_number_of_instances
```
When requesting the Gotenberg service with your client(s), Docker will automatically redirect a request to a Gotenberg container
according to the round-robin strategy.
## Custom implementation
The API relies on a simple YAML configuration file called `gotenberg.yml`. It allows you to tweak some values and even provides you
a way to change the commands called for each kind of conversion.
Below the default configuration file:
```yaml
# The port the application will listen to.
port: 3000
logs:
# Accepted values, in order of severity: DEBUG, INFO, WARN, ERROR, FATAL, PANIC.
# Messages at and above the selected level will be logged.
level: "INFO"
# Accepted values: text, json.
# When a TTY is not attached, the output will be in the defined format.
formatter: "text"
# You don't like a library which is used for a conversion? You want to handle a new file type?
# You may provide here your own implementation!
commands:
# Some libraries like unoconv cannot perform concurrent conversions. That's why the API does only one conversion at a time.
# If your current implementation uses libraries which are able to perform concurrent conversions, you may
# change this value to false.
lock: true
# Unlike others commands' templates, you have access to FilesPaths instead of FilePath: it gathers all PDF files which should be merged.
merge:
template: "pdftk {{ range $filePath := .FilesPaths }} {{ $filePath }} {{ end }} cat output {{ .ResultFilePath }}"
interpreter: "/bin/sh -c"
timeout: 30
# You may add more commands (or less, or even none).
conversions:
# The command template: you have access to FilePath and ResultFilePath variables.
- template: "markdown-pdf {{ .FilePath }} -o {{ .ResultFilePath }}"
# The binary which will call the command.
interpreter: "/bin/sh -c"
# Duration in seconds after which the command will be killed if it has not finished.
timeout: 30
# Files with the following extensions will be converted by the current command.
extensions:
- ".md"
- template: "xvfb-run -e /dev/stdout wkhtmltopdf {{ .FilePath }} {{ .ResultFilePath }}"
interpreter: "/bin/sh -c"
timeout: 30
extensions:
- ".html"
- ".htm"
- template: "unoconv --format pdf --output \"{{ .ResultFilePath }}\" \"{{ .FilePath }}\""
interpreter: "/bin/sh -c"
timeout: 30
extensions:
- ".doc"
- ".docx"
- ".odt"
- ".xls"
- ".xlsx"
- ".ods"
- ".ppt"
- ".pptx"
- ".odp"
```
We provide binaries for a wide range of OS and architecture in the [releases page](../../releases),
so feel free to create your own Docker image for your implementation of the Gotenberg API :metal:
## Clients
* https://github.com/thecodingmachine/gotenberg-php-client (PHP client)
* Add your own client by submitting a [pull request](../../pulls)!
---
Would you like to update this documentation ? Feel free to open an [issue](../../issues).