Host Troubleshooting
The primary wasmCloud host runtime is the wasmcloud-host
, which you'll be using if you're running the host from wash, a released binary, or with the wasmcloud docker image.
The Javascript host has different log messages, and it's recommended to create an issue in the wasmcloud-js repo if you are running into errors in the browser.
The first place to check when troubleshooting the host is logs. wasmCloud host logs include the following:
- Logs from the host runtime
- Logs from actors
- Logs from capability providers
Finding the Logs​
- wash
- Docker
If you followed the installation guide, then you likely started the host by running wash up
. By default, the logs will be printed to the screen, but if you ran the host using --detached
, the logs will be written to ~/.wash/downloads/wasmcloud.log
.
At the start of this logfile you'll see something like:
2023-12-19T21:36:49.708714Z INFO async_nats::options: event: connected
2023-12-19T21:36:49.708910Z INFO async_nats::options: event: connected
2023-12-19T21:36:49.711351Z INFO wasmcloud_host::wasmbus: bucket already exists. Skipping creation. bucket=LATTICEDATA_default
2023-12-19T21:36:49.712048Z INFO wasmcloud_host::wasmbus: bucket already exists. Skipping creation. bucket=CONFIGDATA_default
2023-12-19T21:36:49.714279Z INFO wasmcloud_host::wasmbus: wasmCloud host started host_id="NBNHZROISSPTB4U77L53USB47S5A7HWETPCVAENGYLTWHMKR2B7Q37VT"
Logs are appended to the end of this file as they are generated, so for the latest logs, you'll want to check the end of the file. On Unix systems, you can use the tail
command to see the last several lines of the file, and you can use tail -f
to stream new logs as they are written.
If you ran the wasmCloud host inside a docker container, you can use the docker logs
command to view the logs. To find the name of the wasmCloud host container, run:
docker ps -a --format "table {{.Image}}\t{{.Names}}"
You should see output like:
IMAGE NAMES
wasmcloud/wasmcloud:latest docker-wasmcloud-1
Then you can view the logs by running:
docker logs -f docker-wasmcloud-1
Changing the log level​
To configure the log level, you can use the --log-level
flag, or set the WASMCLOUD_LOG_LEVEL
environment variable, when starting the host.
The wasmCloud host supports the following log levels:
error
warn
info
(default)debug
trace
If you want to configure the log level for a specific library, you can set the RUST_LOG
environment variable. For example, to change the log level of async-nats
to warn
while keeping the host at debug
, you could run:
RUST_LOG=async_nats=warn,debug wasmcloud --log-level debug
Note that all actors and providers inherit the same log level settings as the host itself.
Log Format​
By default, the wasmCloud host emits logs as unstructured text. However, structured logs can be enabled via the --enable-structured-logging
flag, or by setting the WASMCLOUD_STRUCTURED_LOGGING_ENABLED
environment variable to true
. Structured logs are convenient when forwarding logs to an aggregation tool.
Structured logs look like the following:
{"timestamp":"2023-12-19T22:16:06.389492Z","level":"INFO","fields":{"message":"event: connected"},"target":"async_nats::options"}
{"timestamp":"2023-12-19T22:16:06.390689Z","level":"INFO","fields":{"message":"event: connected"},"target":"async_nats::options"}
{"timestamp":"2023-12-19T22:16:06.401737Z","level":"INFO","fields":{"message":"bucket already exists. Skipping creation.","bucket":"LATTICEDATA_default"},"target":"wasmcloud_host::wasmbus"}
{"timestamp":"2023-12-19T22:16:06.402034Z","level":"INFO","fields":{"message":"bucket already exists. Skipping creation.","bucket":"CONFIGDATA_default"},"target":"wasmcloud_host::wasmbus"}
{"timestamp":"2023-12-19T22:16:06.406203Z","level":"INFO","fields":{"message":"wasmCloud host started","host_id":"NC3CUT4IP43REAEQDE33652YNK4Z7KFE7KI3XGUMHVNSP2TNY3CFAH4M"},"target":"wasmcloud_host::wasmbus"}