cat'a-dog

Quick start

git clone https://github.com/DataDog/catadog
cd catadog
bundle install
bundle exec catadog

Now start your agent and app!

Remember to do either one of:

• configure your app's agent connection to hit on the correct port
• configure your agent to listen to another port, and have catadog listen on 8126 as the default and point to the new agent's port by using the settings below

Examples

Change listening host and port (defaults to 127.0.0.1:8128)

bundle exec catadog -h 0.0.0.0 -p 8888

Change agent host and port to proxy to (defaults to 127.0.0.1:8126)

bundle exec catadog --agent-host 10.1.2.3 --agent-port 8127

Silence WEBrick logs (they're on stderr):

bundle exec catadog 2>/dev/null

Record stuff (they're on stdout):

bundle exec catadog > dump.json

Record stuff, one file per request:

bundle exec catadog --record

Use the sink mock, and don't forward to a real agent (mock route misses fall back to 404):

bundle exec catadog --mock :Sink --no-forward

Bring your own mock! (you can use --mock multuiple times)

bundle exec catadog --mock /path/to/mock.rb:MockMiddlewareClass --no-forward

Select specific areas:

bundle exec catadog | jq 'select(.kind=="info")'
bundle exec catadog | jq 'select(.kind=="traces")
bundle exec catadog | jq 'select(.kind=="telemetry")'
bundle exec catadog | jq 'select(.kind=="rc")'

Show only request body of traces that have a span name rack.request:

bundle exec catadog | jq 'select(.kind=="traces") | .request.body | .[] | select(.[].name == "rack.request")'

Ask telemetry if appsec is enabled:

bundle exec catadog | jq 'select(.kind=="telemetry") | .request.body | .payload.additional_payload | .[] | select(.name == "appsec.enabled")'

Ask telemetry the list of reported dependencies and their versions, formatted as tab separated:

bundle exec catadog | jq 'select(.kind=="telemetry") | .request.body | .payload.dependencies | .[] | [.name, .version] | @tsv' -r

Ask telemetry which integrations are enabled:

bundle exec catadog | jq 'select(.kind=="telemetry") | .request.body | .payload.integrations | .[] | select(.enabled)'

Show RC client config state as it evolves:

bundle exec catadog | jq 'select(.kind=="rc") | .request.body.client.state.config_states'

Show RC client cached targets as they evolve:

bundle exec catadog | jq 'select(.kind=="rc") | .request.body.cached_target_files'

Show RC targets as they are received:

bundle exec catadog | jq 'select(.kind=="rc") | .response.body.target_files'

Show RC targets in both request and response as they evolve:

bundle exec catadog | jq 'select(.kind=="rc") | { cached: .request.body.cached_target_files | map(.path), received: .response.body.targets.signed.targets }'

Show the contents of the ASM_DD product traget as it is received

bundle exec catadog | jq 'select(.kind=="rc") | .response.body.target_files | .[] | select(.path | test("ASM_DD"))'

Show the contents of the crs-913-110 rule as it is received:

bundle exec catadog | jq 'select(.kind=="rc") | .response.body.target_files | .[] | select(.path | test("ASM_DD")) | .parsed.rules | .[] | select(.id == "crs-913-110")'

Show the contents of the blocked ips list:

bundle exec catadog | jq 'select(.kind=="rc") | .response.body.target_files | .[] | select(.path | test("ASM_DATA/blocked_ips"))'

The big idea

dd-trace-cat

• at DataDog/dd-trace-cat
• node project
• sink for /v0.4/traces only
• dumb '200 OK' as response

catadog

• support everything else
• decode known encoded content
• use Unix as IDE
• answer properly

TODO:

• cli: better interface (command args)
• traces: output .dot format (graphviz + sixel)
• traces: GUI like dd-trace-cat
• all: mock (static, dynamic)
• all: record, replay