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node-lookup/AGENTS.md
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unkinben 103ebb2393
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Support comma-separated -F for querying multiple facts
`node-lookup -jF ipaddress,enc_role` returned `{}` because it queried a single
fact literally named "ipaddress,enc_role". Requesting several facts per host is
a natural need (e.g. pairing an address with its role).

- Split -F on commas (splitFactNames) and match any of them via an "or" over
  ["=","name",<n>] clauses (nameFilter); a single name keeps the plain "="
  form.
- Key JSON output by each result's real fact name so all requested facts appear
  under the host (previously keyed by the raw -F string).
- Update the -F flag help and add unit tests (split, single vs multi query
  shape, multi-fact JSON).
2026-07-05 17:16:07 +10:00

145 lines
6.7 KiB
Markdown

# AGENTS.md
## Project Overview
`node-lookup` is a Go CLI tool that queries a PuppetDB API to retrieve and filter node facts.
## Structure
```
main.go # entire application source
main_test.go # unit tests (mock PuppetDB via httptest, no live deps)
go.mod # Go module (module name: node-lookup)
go.sum # dependency checksums
Makefile # build / test / lint / completions / rpm / version-bump targets
packaging/nfpm.yaml # nfpm spec (envsubst-templated) for the RPM
scripts/build-rpm.sh # generates completions + packages the RPM with nfpm
.woodpecker/ # CI: build, test, pre-commit (PR) + release (tag)
dist/ # build output: binary, completions, RPM (not committed)
```
## Build
```bash
make build # -> dist/node-lookup (CGO disabled, static)
# or directly:
go build -o node-lookup ./...
```
Requires Go 1.21+. Dependencies: `github.com/spf13/cobra` (CLI), `gopkg.in/yaml.v3` (Ansible output).
## Packaging (RPM)
```bash
make rpm # build the binary + package it into dist/*.rpm via nfpm
```
`scripts/build-rpm.sh` generates bash/zsh/fish completions from the built binary
and bundles them alongside `/usr/bin/node-lookup`. On a `v*` tag the release
pipeline builds the RPM and `PUT`s it to the artifactapi `rpm-internal` repo.
## Shell completions
Cobra provides a `completion` subcommand:
```bash
node-lookup completion bash # or zsh / fish / powershell
```
The RPM installs completions to the standard system paths
(`/usr/share/bash-completion/completions/`, `/usr/share/zsh/site-functions/`,
`/usr/share/fish/vendor_completions.d/`), so they work automatically once
installed. To load ad-hoc in the current shell, e.g. zsh:
`source <(node-lookup completion zsh)`.
## Running the Tool
```bash
./node-lookup --help
./node-lookup -R # show all nodes with role fact
./node-lookup -n <hostname> # lookup a specific node
./node-lookup -F <fact_name> # filter by fact name
./node-lookup -jF ipaddress,enc_role # several facts at once (comma-separated)
./node-lookup -R -m <value> # exact value match (-m)
./node-lookup -R -pm <value> # partial/regex match (-p -m combined)
./node-lookup -R -im <value> # inverse exact match (-i -m combined)
./node-lookup -R -ipm <value> # inverse partial match (-i -p -m combined)
./node-lookup -R -p <value> # value may also be given positionally
./node-lookup -R -1 # node names only
./node-lookup -R -2 # values only
./node-lookup -R -C # count occurrences
./node-lookup -R -A # output as Ansible YAML inventory
./node-lookup -j # output as JSON { host → { fact → value } }
./node-lookup --url http://host:8080/... # override PuppetDB URL for this invocation
echo -e "node1\nnode2" | ./node-lookup -R # pipe node names via stdin
```
## Configuration
Precedence (lowest → highest): **defaults < config file < env vars < `--url` flag**
### Config file
XDG location: `$XDG_CONFIG_HOME/node-lookup/config.yaml` (default: `~/.config/node-lookup/config.yaml`)
```yaml
puppetdb_url: http://puppetdbapi.service.consul:8080/pdb/query/v4/facts
role_fact: enc_role
```
Generate the default config file:
```bash
./node-lookup config init
```
Show the active configuration (after all overrides applied):
```bash
./node-lookup config show
```
### Environment variables
| Variable | Config key | Description |
|---|---|---|
| `NODE_LOOKUP_URL` | `puppetdb_url` | PuppetDB facts endpoint |
| `NODE_LOOKUP_ROLE_FACT` | `role_fact` | Fact name used by `-R` flag |
### CLI flag
`--url <url>` overrides the PuppetDB URL for a single invocation (highest precedence).
## Code Patterns
- **`loadConfig()`**: reads config file → applies env vars → returns `config` struct. Called once at startup in `main()`.
- **`buildQuery()`**: returns a PuppetDB PQL-compatible JSON array string. Uses `roleFact` from config (not hardcoded). Match modifiers: `-p` (partial/regex, uses `~` op), `-i` (inverse, wraps with `not`), composable.
- **Multiple facts**: `-F` accepts a comma-separated list (`ipaddress,enc_role`). `splitFactNames()`/`nameFilter()` turn several names into an `or` over `["=","name",<n>]` clauses; JSON output keys each value by the fact's real name so all requested facts appear per host.
- **Match value / `matchValue()`**: the value to match comes from `-m/--match` or, if that is empty, an optional positional argument. The positional fallback exists because pflag does not attach a space-separated value to a string flag grouped with a bool flag, so in `-pm k8s` the `k8s` arrives as a positional. `-m` still wins when both are given.
- **`queryPuppetDB(url, query)`**: takes the URL as a parameter — never reads globals.
- **`processResults()`**: iterates facts, returns sorted `"certname value"` strings. JSON string values are unquoted; other JSON types rendered as compact JSON.
- **Output modes**: JSON (`-j`), count (`-C`), Ansible YAML (`-A`), node-only (`-1`), value-only (`-2`), default (node + value).
- **Stdin support**: `stdinReader()` reads node names from stdin only when it is a real pipe/redirect carrying data (and no `-n` given). Terminals, `/dev/null`, and empty/closed pipes fall through to a normal query — so running without a TTY (e.g. invoked by an agent or CI) behaves like an interactive run instead of consuming empty input.
- **SIGPIPE handling**: `signal.Ignore(syscall.SIGPIPE)` so pipes to `head` etc. work cleanly.
## CLI Framework
Uses [Cobra](https://github.com/spf13/cobra). Root command is the query command. `config` is a subcommand with `init` and `show` sub-subcommands.
## Testing
```bash
make test # go test -v -race ./...
```
`main_test.go` covers query construction (all `-m`/`-p`/`-i` combinations), value
rendering, result processing/counting, config precedence (defaults < file < env),
`writeDefaultConfig`, the `stdinReader` no-TTY behavior, and every `run()` output
mode (default, `-1`, `-2`, `-C`, `-j`, `-A`, `-a`). PuppetDB is stubbed with
`httptest` — no live Consul/PuppetDB access is required.
## Gotchas
- `-1`, `-2`, `-C`, and `-A` all require `-R` or `-F`; the tool exits with an error otherwise.
- `-C` (count) with stdin reads all lines as pre-fetched `"node value"` output for counting — it does **not** query PuppetDB per line.
- JSON output (`-j`) builds `{ hostname: { factname: value } }` keyed by each result's actual fact name (so `-F ipaddress,enc_role` yields both per host); it falls back to the `-F` value, the `role_fact` config value (if `-R`), or `"value"` only when a result carries no name.
- `config init` fails if the config file already exists (will not overwrite).