Dagger system shell : how to reuse / inherit container ?

[fierce ridge]

Hi
I try the new feature from 0.17: https://docs.dagger.io/features/shell/
here is my first file:

container |
  from alpine |
  with-exec apk add curl |
  with-exec -- sh -c 'curl -fsSL https://dl.dagger.io/dagger/install.sh | BIN_DIR=/bin sh'

how can I reuse this base for each other files ?

or how can I setup variables ?

[strange viper]

You can set variables, then reuse them in other pipelines

regular bash syntax, myctr=$(container | ...)

also you can use container | with-file /tmp/install.sh $(http https://dl.dagger.io/install.sh) | with-exec /tmp/install.sh

(to avoid installing curl, and get better caching on the download)

[fierce ridge]

is it possible to have multiple files ? or each variable (and logic) should be inside the same file ?

for example I do this:

docker=$(container |
  from alpine |
  with-exec apk add docker |
  with-unix-socket /var/run/docker.sock /var/run/docker.sock)

dagger=$($docker |
  with-exec apk add curl |
  with-exec -- sh -c 'curl -fsSL https://dl.dagger.io/dagger/install.sh | BIN_DIR=/bin sh'
)

# $dagger |
#   with-workdir /benchmark-go |
#   with-exec -- dagger init --sdk=go . |
#   with-exec time dagger functions |
#   stderr

$dagger |
  with-workdir /benchmark-php |
  with-exec -- dagger init --sdk=php . |
  with-exec time dagger functions |
  stderr

I would like to be able to test this for each versions of dagger, each sdk, ...

[fierce ridge]

the scripts need curl 🤷‍♂️ so I guess I will keep my version for now

[strange viper]

Ha ha 🙂 Didn't think of that

[strange viper]

You can use standard bash syntax like if/else/then; for; etc. At some point you may decide that it's too much for bash, in which case you would move it to a module, with small clean typed functions in a proper language 🙂

for simple cases you can also take advantage of the "fan-out" feature of dagger pipelines: if you call a function that returns a list of objects, the next function in the chain will be called against all elements of the array in parallel

[fierce ridge]

I see 🙂
if you have a link to the documentation, I take it

[strange viper]

For creating a module?

[fierce ridge]

the fan-out feature

[strange viper]

I'm not sure the fan-out feature is documented 😬 kind of a niche "advanced" feature. Let me check

The main reason is that the core API doesn't return a lot of lists of objects. But when you develop your own module, it becomes much more powerful, because you can write functions that return lists of objects, and so can other modules. That's when fan-out can become a nice cheat code

[fierce ridge]

Thank you Solomon 🙂

[strange viper]

np, keep me posted, I'm interested in seeing what you do with Dagger 🙂

[fierce ridge]

I rewrite it in Go: https://github.com/mykiwi/dagger-sdk-benchmark
but I'm still new with dagger and I don't know how to chain logic, for example in the README I did:

$ BASE_ID=$(dagger call container-base --dockerSocket /var/run/docker.sock)

$ CODE_PHP_ID=$(dagger call container-code --container $BASE_ID --language php)

but it does not works 🤔

[fierce ridge]

oh I think I get it... I must do this chaining inside an other go function

[strange viper]

yes it looks like what you want is to call some of your functions from others.

it looks like maybe containerCode() should call containerBase()?

@fierce ridge to chain from the command line you need to use the dagger shell, not dagger call.

[fierce ridge]

👌 thx