# Installing Kapow! Kapow! has a reference implementation in Go that is under active development right now. If you want to start using Kapow! you can: * Download a binary (linux, at this moment) from our [releases](https://github.com/BBVA/kapow/releases) section * Install the package with the `get` command (you need the Go runtime installed and [configured](https://golang.org/cmd/go/)) ```sh go get -u github.com/BBVA/kapow ``` # Examples Below are some examples on how to define and invoke routes in Kapow! As you will see `kapow` binary is both a server and a CLI that you can use to configure a running server. The server exposes an [API](/spec#http-control-api) that you can use directly if you want. In order to get information from the request that fired the script execution and to help you compose the response, the server exposes some [resources](/spec#handlers) to interact with from the script. ## The mandatory Hello World (for WWW fans) First, you create a pow file named `greet.pow` with the following contents: ```sh kapow route add /greet -c 'name=$(kapow get /request/params/name); echo Hello ${name:-World} | kapow set /response/body' ``` note that you have to escape it as the command will run on a shell itself. Then, you execute: ```sh kapow server greet.pow ``` to start a Kapow! server exposing your service. Now you can check that it works as intended with good ole’ `curl`: ```sh curl localhost:8080/greet Hello World curl localhost:8080/greet?name=friend Hello friend ``` If you want to work with JSON you can use this version of the pow `greet-json.pow` ```sh kapow route add -X POST /greet -c 'who=$(kapow get /request/body | jq -r .name); kapow set /response/status 201; jq --arg value "${who:-World}" -n \{name:\$value\} | kapow set /response/body' ``` that uses [jq](https://stedolan.github.io/jq/) to allow you to work with JSON from the command line. Check that it works with ```sh curl -X POST -H 'Content-Type: application/json' -d '{"name": "friend"}' localhost:8080/greet {"name": "friend" } curl -X POST -H 'Content-Type: application/json' -d '' localhost:8080/greet {"name": "World"} ``` ## The mandatory Echo (for UNIX fans) First, you create a pow file named `echo.pow` with the following contents: ```sh kapow route add -X POST /echo -c 'kapow get /request/body | kapow set /response/body' ``` then, you execute: ```sh kapow server echo.pow ``` and you can check that it works as intended with good ole’ `curl`: ```sh curl -X POST -d '1,2,3... testing' localhost:8080/echo 1, 2, 3, 4, 5, 6, 7, 8, 9, testing ``` If you send a big file and want to see the content back as a real-time stream you can use this version `echo-stream.pow` ```sh kapow route add -X POST /echo -c 'kapow get /request/body | kapow set /response/stream' ``` ## The multiline fun Unless you're a hardcore Perl golfer, you'll probably need to write your stuff over more than one line in order to avoid the mess we saw on our JSON greet version. Don't worry, we need to write several lines, too. Bash, in its magnificent UNIX® style, provides us with the [here-documents](https://www.gnu.org/software/bash/manual/bash.html#Here-Documents) mechanism that we can leverage precisely for this purpose. Imagine that we want to return both the standard output and a generated file from a command execution. Let's write a `log-and-stuff.pow` file with the following content: ```sh kapow route add /log_and_stuff - <<-'EOF' echo this is a quite long sentence and other stuff | tee log.txt | kapow set /response/body cat log.txt | kapow set /response/body EOF ``` then we serve it with `kapow`: ```sh kapow server log-and-stuff.pow ``` Yup. As simple as that. You can check it. ```sh curl localhost:8080/log_and_stuff this is a quite long sentence and other stuff this is a quite long sentence and other stuff ``` ## Interact with other systems You can leverage all the power of the shell in your scripts and interact with other systems by using all the available tools. Write a `log-and-stuff-callback.pow` file with the following content: ```sh kapow route add /log_and_stuff - <<-'EOF' callback_url="$(kapow get /request/params/callback)" echo this is a quite long sentence and other stuff | tee log.txt | kapow set /response/body echo sending to $callback_url | kapow set /response/body curl -X POST --data-binary @log.txt $callback_url | kapow set /response/body EOF ``` serve it with `kapow`: ```sh kapow server log-and-stuff-callback.pow ``` and finally check it. ```sh curl localhost:8080/log_and_stuff?callback=nowhere.com this is a quite long sentence and other stuff sending to nowhere.com 405 Not Allowed

405 Not Allowed

nginx
``` You must be aware that you must have all the dependencies you use in your scripts installed in the host that will run the Kapow! server. In addition, a pow file can contain as many routes as you like, so you can start a server with several routes configured in one shot. # Sample Docker usage ## Clone the project ```sh git clone https://github.com/BBVA/kapow.git ``` ## Build the kapow! docker image ```sh make docker ``` Now you have a container image with all the above pow files copied in /tmp so you can start each example by running ```sh docker run --rm -p 8080:8080 docker server example.pow ``` ## Build a docker image for running the nmap example ```sh cd /path/to/kapow/poc/examples/nmap; docker build -t kapow-nmap . ``` ## Run kapow ```sh docker run \ -d \ -p 8080:8080 \ kapow-nmap ``` which will output something like this: ```sh e7da20c7d9a39624b5c56157176764671e5d2d8f1bf306b3ede898d66fe3f4bf ``` ## Test /list endpoint In another terminal, try running: ```sh curl http://localhost:8080/list/github.com ``` which will respond something like: ```sh Starting Nmap 7.70 ( https://nmap.org ) at 2019-05-10 14:01 UTC Nmap scan report for github.com (140.82.118.3) rDNS record for 140.82.118.3: lb-140-82-118-3-ams.github.com Nmap done: 1 IP address (0 hosts up) scanned in 0.04 seconds ``` et voilà ! # License This project is distributed under the [Apache License 2.0](/LICENSE).