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name : "Running a Real Module Against This C++ SDK"
output : cpp-sdk-module-runtime.md
release : ""
intro : |
`logos-cpp-sdk` is the foundation every other Logos component is built on: it
pins nixpkgs/Qt and ships the SDK that `logos-liblogos` (`logos_host`,
`liblogos_core`), the module client, and every module compile and link against
— `LogosAPI`, `LogosResult`, the IPC layer, and the code generator. A change
here ripples through the entire stack, so the way to know it is safe is to run
a real module on top of it. This doc-test does exactly that, end-to-end through
the headless `logoscore` runtime:
1. Build the `logoscore` CLI, **overriding `logos-cpp-sdk` with the commit
under test** — and overriding it in the same way for every consumer in
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`logoscore`'s closure (`logos-liblogos` and the `capability_module`'s
`logos-module-builder`). Because the published flakes pin the SDK
independently (there is no single `follows` unifying them), all of these
must point at the same commit so the whole runtime is built and linked
against one consistent SDK ABI. Each `logos-qt-sdk` dragged onto the new
SDK also gets its sibling `logos-lidl` moved with it — see the note in
the first section.
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2. Build the `lgpm` local package manager.
3. Build the real [`accounts_module`](https://github.com/logos-co/logos-accounts-module)
as an `.lgx` package straight from its own flake — **also built against the
SDK commit under test** — and install it into a `./modules` directory with
`lgpm`.
4. Start `logoscore` in daemon mode (`-D`), load `accounts_module`, introspect
it, and call its methods — verifying a module compiled against this SDK
actually loads and round-trips real values over the SDK's IPC.
Because every layer (host, module loader, IPC, and the module itself) is built
against the SDK commit under test, a green run is real evidence that this
change keeps the module runtime working from the bottom of the stack up.
what_you_build : "The real `accounts_module`, installed with `lgpm` and called through a `logoscore` daemon — every layer compiled against this C++ SDK commit."
what_you_learn :
- How to build `logoscore` against a specific `logos-cpp-sdk` commit by overriding it across every consumer in the closure
- Why a foundational input pinned independently by several flakes needs the override applied at each consumer, not just once
- How to build a real module's `.lgx` against the same SDK commit
- How to install an `.lgx` into a modules directory with `lgpm`
- How to start the `logoscore` daemon, load a module, and call its methods
prerequisites :
- |
**Nix** with flakes enabled. Install from [nixos.org](https://nixos.org/download.html), then enable flakes:
```bash
mkdir -p ~/.config/nix
echo 'experimental-features = nix-command flakes' >> ~/.config/nix/nix.conf
```
Verify: `nix flake --help >/dev/null 2>&1 && echo "Flakes enabled"`
- "**git** — to clone the module repository."
- "A Linux or macOS machine."
sections :
- title : "Build logoscore against this C++ SDK"
step : true
text : |
Build the `logoscore` CLI from its published flake, but **override
`logos-cpp-sdk` to the commit under test** — and apply the same override to
every consumer that pins the SDK in `logoscore`'s closure. The result is
symlinked to `./logos/`.
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> Unlike a leaf input, the SDK is pinned independently by `logos-liblogos`
> and the `capability_module`'s `logos-module-builder` — there is no single
> `follows` tying them together in the published flakes. So we override it
> at each of those paths (e.g.
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> `--override-input logos-liblogos/logos-cpp-sdk …`) to keep the whole
> runtime on one consistent SDK ABI. Each override URL carries a `{release}`
> placeholder the doc-test runner expands to a concrete ref: locally that is
> this checkout's `HEAD` (see `run.sh`); in CI it is the commit being
> tested. With no pin it falls back to latest `master`.
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> **Why the `logos-qt-sdk/logos-lidl` overrides.** This SDK installs
> `share/lidl-frontend/lidl_compat.h`, and `logos-qt-sdk`'s
> `logos-qt-generator` *compiles* that header against **its own**
> `logos-lidl` input. `logos-lidl` is a **sibling** of `logos-cpp-sdk`
> under `logos-qt-sdk`, not a descendant, so overriding the SDK moves the
> header forward while qt-sdk keeps its older lidl — and the generator
> fails to compile the shim. Each `logos-qt-sdk` node that ends up on the
> SDK under test therefore needs its `logos-lidl` moved with it.
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steps :
- title : "Build the CLI with the SDK override"
run : |
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nix build 'github:logos-co/logos-logoscore-cli{release}' \
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--override-input logos-cpp-sdk 'github:logos-co/logos-cpp-sdk{release}' \
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--override-input logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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--override-input logos-liblogos/logos-cpp-sdk 'github:logos-co/logos-cpp-sdk{release}' \
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--override-input logos-liblogos/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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--override-input logos-capability-module/logos-module-builder 'github:logos-co/logos-module-builder{release}' \
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--override-input logos-capability-module/logos-module-builder/logos-cpp-sdk 'github:logos-co/logos-cpp-sdk{release}' \
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--override-input logos-capability-module/logos-module-builder/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
--override-input logos-capability-module/logos-module-builder/logos-test-framework/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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--out-link ./logos
code_block : |
nix build 'github:logos-co/logos-logoscore-cli' \
--override-input logos-cpp-sdk 'github:logos-co/logos-cpp-sdk' \
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--override-input logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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--override-input logos-liblogos/logos-cpp-sdk 'github:logos-co/logos-cpp-sdk' \
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--override-input logos-liblogos/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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--override-input logos-capability-module/logos-module-builder/logos-cpp-sdk 'github:logos-co/logos-cpp-sdk' \
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--override-input logos-capability-module/logos-module-builder/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
--override-input logos-capability-module/logos-module-builder/logos-test-framework/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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--out-link ./logos
check_file : "logos/bin/logoscore"
post_text : |
The build produces `logos/bin/logoscore` plus bundled runtime libraries
and a `logos/modules/` directory containing the built-in
`capability_module` (required for the auth handshake when loading
modules). Every overridden input resolves to the same SDK commit, so
`logos_host`, `liblogos_core`, the module client, and the capability
module are all rebuilt and linked against this SDK.
- title : "Build the lgpm package manager"
step : true
text : |
`lgpm` installs `.lgx` packages into a modules directory and scans what is
installed. Build it from the `logos-package-manager` flake and link it as
`./lgpm`. (`lgpm` is plain C++ with no SDK dependency, so it needs no
override.)
steps :
- title : "Build lgpm"
run : "nix build 'github:logos-co/logos-package-manager#cli' -o lgpm"
check_file : "lgpm/bin/lgpm"
post_text : "The executable is at `./lgpm/bin/lgpm`."
- title : "Build and install the accounts module against this SDK"
step : true
text : |
Clone [`logos-accounts-module`](https://github.com/logos-co/logos-accounts-module),
build its `.lgx` straight from its flake's `#lgx` output **against the SDK
commit under test**, and install it into a local `./modules` directory with
`lgpm`. Building the module against the same SDK as the runtime keeps the
plugin ABI-compatible with the host that will load it. Every module built
with [`logos-module-builder`](https://github.com/logos-co/logos-module-builder)
exposes a ready-to-install `#lgx`, and the builder owns the module's SDK
pin — so the override path here is
`logos-module-builder/logos-cpp-sdk`.
steps :
- title : "Clone the module"
text : |
We clone over HTTPS so the step works in CI; over SSH the URL is
`git@github.com:logos-co/logos-accounts-module.git`.
run : "git clone --depth 1 https://github.com/logos-co/logos-accounts-module.git"
check_file : "logos-accounts-module/flake.nix"
- title : "Build the module's .lgx against this SDK"
text : |
Build the `#lgx` output, overriding the module builder's `logos-cpp-sdk`
to the commit under test, and link it as `./accounts-lgx`. (This
compiles the module and its SDK dependencies through Nix, so the first
build is slow.)
run : |
nix build 'path:./logos-accounts-module#lgx' \
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--override-input logos-module-builder 'github:logos-co/logos-module-builder{release}' \
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--override-input logos-module-builder/logos-cpp-sdk 'github:logos-co/logos-cpp-sdk{release}' \
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--override-input logos-module-builder/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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-o accounts-lgx
code_block : |
# From inside the clone this is simply:
# nix build '.#lgx' --override-input logos-module-builder/logos-cpp-sdk 'github:logos-co/logos-cpp-sdk'
nix build 'path:./logos-accounts-module#lgx' \
--override-input logos-module-builder/logos-cpp-sdk 'github:logos-co/logos-cpp-sdk' \
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--override-input logos-module-builder/logos-qt-sdk/logos-lidl 'github:logos-co/logos-lidl' \
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-o accounts-lgx
post_text : "The `.lgx` package is now under `./accounts-lgx/`:"
extra_run :
run : "ls accounts-lgx/*.lgx"
- title : "Seed the modules directory with the bundled capability module"
text : |
`accounts_module` is loaded through the host's capability layer, so the
modules directory also needs the `capability_module` that ships with
`logoscore` (and that we just rebuilt against this SDK). Copy it across
first.
run : |
mkdir -p modules
cp -RL ./logos/modules/. ./modules/
check_file : "modules/capability_module/manifest.json"
- title : "Install the .lgx with lgpm"
text : |
Install the freshly-built package into `./modules`. `accounts_module` is
a `core` module, so it goes to `--modules-dir`. The package is unsigned
(a local dev build), so we pass `--allow-unsigned`.
run : "./lgpm/bin/lgpm --modules-dir ./modules --allow-unsigned install --file accounts-lgx/*.lgx"
expect_contains :
- "Installed to:"
- title : "Confirm the install"
text : "Scan the directory and confirm the module landed:"
run : "./lgpm/bin/lgpm --modules-dir ./modules list"
expect_contains :
- "accounts_module"
check_file : "modules/accounts_module/manifest.json"
- title : "Run the daemon and call the module"
step : true
text : |
Start `logoscore` in daemon mode pointed at `./modules`, then use the client
subcommands to load `accounts_module`, introspect it, and call its methods.
Daemon output is captured in `logs.txt`.
steps :
- title : "Start the daemon"
text : |
Start logoscore in daemon mode in the background, capturing output to
`logs.txt`:
run : "sh -c './logos/bin/logoscore -D -m ./modules > logs.txt 2>&1 &'"
code_block : "logoscore -D -m ./modules > logs.txt &"
post_text : |
The `-D` flag starts the daemon. The client subcommands below connect to
this running process via the config written under `~/.logoscore/`.
- run : "sleep 3"
- title : "Inspect the startup log"
text : "Review the daemon's startup output:"
run : "cat logs.txt"
- title : "Check daemon status"
text : "Verify the daemon is running:"
run : "./logos/bin/logoscore status"
code_block : "logoscore status"
- title : "List discovered modules"
text : "`accounts_module` should be visible in the scan directory:"
run : "./logos/bin/logoscore list-modules"
code_block : "logoscore list-modules"
expect_contains :
- "accounts_module"
- title : "Load the module"
text : "Load `accounts_module` into the running daemon:"
run : "./logos/bin/logoscore load-module accounts_module"
code_block : "logoscore load-module accounts_module"
expect_contains :
- "accounts_module"
- title : "Confirm the module is loaded"
text : |
Re-run `status`; the module that was `not_loaded` before now reports
`loaded`:
run : "./logos/bin/logoscore status"
code_block : "logoscore status"
expect_contains :
- "accounts_module"
- '"status":"loaded"'
- title : "Introspect the module with module-info"
text : |
`module-info` lists the `Q_INVOKABLE` methods the module exposes — the
same methods you can `call`. Each one is dispatched over the SDK's IPC
layer:
run : "./logos/bin/logoscore module-info accounts_module"
code_block : "logoscore module-info accounts_module"
expect_contains :
- "accounts_module"
- "createRandomMnemonic"
- title : "Call a method"
text : |
Generate a fresh 12-word BIP-39 mnemonic. `createRandomMnemonic` takes
the word count and returns the phrase — a real round-trip dispatched
over the SDK's IPC layer into the module compiled against this SDK:
run : "./logos/bin/logoscore call accounts_module createRandomMnemonic 12"
code_block : "logoscore call accounts_module createRandomMnemonic 12"
expect_contains :
- '"result"'
- title : "Call a second method"
text : |
`lengthToEntropyStrength` maps a mnemonic word count to its entropy
strength in bits — 12 words is 128 bits. This exercises an `int`
round-trip through `LogosResult` over the SDK's IPC:
run : "./logos/bin/logoscore call accounts_module lengthToEntropyStrength 12"
code_block : "logoscore call accounts_module lengthToEntropyStrength 12"
expect_contains :
- '"result":128'
- title : "Stop the daemon"
text : "Shut the daemon down cleanly:"
run : "./logos/bin/logoscore stop"
code_block : "logoscore stop"
post_text : |
The daemon removes its state file and exits.
- run : "sleep 2"
- title : "Confirm the daemon has stopped"
text : |
With no daemon running, the client reports `not_running` and exits
non-zero, so we add `|| true` to let the doc-test assert on the output:
run : "./logos/bin/logoscore status || true"
code_block : "logoscore status"
expect_contains :
- '"status":"not_running"'