Swarm is a distributed storage platform and content distribution service, a native base layer service of the ethereum web3 stack. The primary objective of Swarm is to provide a decentralized and redundant store for dapp code and data as well as block chain and state data. Swarm is also set out to provide various base layer services for web3, including node-to-node messaging, media streaming, decentralised database services and scalable state-channel infrastructure for decentralised service economies.
Table of Contents
- Building the source
- Running Swarm
- Developers Guide
- Public Gateways
- Swarm Dapps
Building the source
It's recommended to use Go 1.13 to build Swarm.
To simply compile the
swarm binary without a
$ git clone https://github.com/ethersphere/swarm $ cd swarm $ make swarm
You will find the binary under
To build a vendored
go get you must have
GOPATH set. Then run:
$ go get -d github.com/ethersphere/swarm $ go install github.com/ethersphere/swarm/cmd/swarm
If you don't have an account yet, then you will be prompted to create one and secure it with a password:
Your new account is locked with a password. Please give a password. Do not forget this password. Passphrase: Repeat passphrase:
If you have multiple accounts created, then you'll have to choose one of the accounts by using the
$ swarm --bzzaccount <your-account-here> # example $ swarm --bzzaccount 2f1cd699b0bf461dcfbf0098ad8f5587b038f0f1
Verifying that your local Swarm node is running
When running, Swarm is accessible through an HTTP API on port 8500.
Confirm that it is up and running by pointing your browser to http://localhost:8500
Ethereum Name Service resolution
The Ethereum Name Service is the Ethereum equivalent of DNS in the classic web. In order to use ENS to resolve names to Swarm content hashes (e.g.
swarm has to connect to a
geth instance, which is synced with the Ethereum mainnet. This is done using the
$ swarm --bzzaccount <your-account-here> \ --ens-api '$HOME/.ethereum/geth.ipc' # in our example $ swarm --bzzaccount 2f1cd699b0bf461dcfbf0098ad8f5587b038f0f1 \ --ens-api '$HOME/.ethereum/geth.ipc'
For more information on usage, features or command line flags, please consult the Documentation.
Swarm documentation can be found at https://swarm-guide.readthedocs.io.
Swarm container images are available at Docker Hub: ethersphere/swarm
latest- latest stable release
edge- latest build from
v0.x.y- specific stable release
Swarm command line arguments
All Swarm command line arguments are supported and can be sent as part of the CMD field to the Docker container.
Running a Swarm container from the command line
$ docker run -it ethersphere/swarm \ --debug \ --verbosity 4
Running a Swarm container with custom ENS endpoint
$ docker run -it ethersphere/swarm \ --ens-api http://22.214.171.124:8545 \ --debug \ --verbosity 4
Running a Swarm container with metrics enabled
$ docker run -it ethersphere/swarm \ --debug \ --metrics \ --metrics.influxdb.export \ --metrics.influxdb.endpoint "http://localhost:8086" \ --metrics.influxdb.username "user" \ --metrics.influxdb.password "pass" \ --metrics.influxdb.database "metrics" \ --metrics.influxdb.host.tag "localhost" \ --verbosity 4
Running a Swarm container with tracing and pprof server enabled
$ docker run -it ethersphere/swarm \ --debug \ --tracing \ --tracing.endpoint 127.0.0.1:6831 \ --tracing.svc myswarm \ --pprof \ --pprofaddr 0.0.0.0 \ --pprofport 6060
Running a Swarm container with a custom data directory mounted from a volume and a password file to unlock the swarm account
$ docker run -it -v $PWD/hostdata:/data \ -v $PWD/password:/password \ ethersphere/swarm \ --datadir /data \ --password /password \ --debug \ --verbosity 4
We assume that you have Go v1.11 installed, and
GOPATH is set.
You must have your working copy under
Most likely you will be working from your fork of
swarm, let's say from
github.com/nirname/swarm. Clone or move your fork into the right place:
$ git clone firstname.lastname@example.org:nirname/swarm.git $GOPATH/src/github.com/ethersphere/swarm
Vendoring is done by Makefile rule
make vendor which uses
go mod vendor and additionally copies cgo dependencies into
vendor directory from go modules cache.
If you want to add a new dependency, run
GO111MODULE=on go get <import-path>, vendor it
make vendor, then commit the result.
If you want to update all dependencies to their latest upstream version, run
GO111MODULE=on go get -u all and vendor them with
go tool will use dependencies defined in
go.mod file from modules cache. In order to import code from
vendor directory, an additional flag
-mod=vendor must be provided when calling
go build and
go install. If
vendor directory is in sync with
go.mod file by updating it with
make vendor, there should be no difference to use the flag or not. All Swarm build tools are using code only from the
vendor directory and it is encouraged to do the same in the development process, as well.
This section explains how to run unit, integration, and end-to-end tests in your development sandbox.
Testing one library:
$ go test -v -cpu 4 ./api
Note: Using options -cpu (number of cores allowed) and -v (logging even if no error) is recommended.
Testing only some methods:
$ go test -v -cpu 4 ./api -run TestMethod
Note: here all tests with prefix TestMethod will be run, so if you got TestMethod, TestMethod1, then both!
$ go test -v -cpu 4 -bench . -run BenchmarkJoin
This section explains how to add Go
pprof profiler to Swarm
swarm is started with the
--pprof option, a debugging HTTP server is made available on port 6060.
You can bring up http://localhost:6060/debug/pprof to see the heap, running routines etc.
By clicking full goroutine stack dump (clicking http://localhost:6060/debug/pprof/goroutine?debug=2) you can generate trace that is useful for debugging.
Metrics and Instrumentation in Swarm
This section explains how to visualize and use existing Swarm metrics and how to instrument Swarm with a new metric.
Swarm metrics system is based on the
The most common types of measurements we use in Swarm are
resetting timers. Consult the
go-metrics documentation for full reference of available types.
// incrementing a counter metrics.GetOrRegisterCounter("network.stream.received_chunks", nil).Inc(1) // measuring latency with a resetting timer start := time.Now() t := metrics.GetOrRegisterResettingTimer("http.request.GET.time"), nil) ... t := UpdateSince(start)
Swarm supports an InfluxDB exporter. Consult the help section to learn about the command line arguments used to configure it:
$ swarm --help | grep metrics
We use Grafana and InfluxDB to visualise metrics reported by Swarm. We keep our Grafana dashboards under version control at https://github.com/ethersphere/grafana-dashboards. You could use them or design your own.
We have built a tool to help with automatic start of Grafana and InfluxDB and provisioning of dashboards at https://github.com/nonsense/stateth, which requires that you have Docker installed.
Once you have
stateth installed, and you have Docker running locally, you have to:
statethand keep it running in the background
$ stateth --rm --grafana-dashboards-folder $GOPATH/src/github.com/ethersphere/grafana-dashboards --influxdb-database metrics
swarmwith at least the following params:
--metrics \ --metrics.influxdb.export \ --metrics.influxdb.endpoint "http://localhost:8086" \ --metrics.influxdb.username "admin" \ --metrics.influxdb.password "admin" \ --metrics.influxdb.database "metrics"
- Open Grafana at http://localhost:3000 and view the dashboards to gain insight into Swarm.
Swarm offers a local HTTP proxy API that Dapps can use to interact with Swarm. The Ethereum Foundation is hosting a public gateway, which allows free access so that people can try Swarm without running their own node.
The Swarm public gateways are temporary and users should not rely on their existence for production services.
The Swarm public gateway can be found at https://swarm-gateways.net and is always running the latest
stable Swarm release.
You can find a few reference Swarm decentralised applications at: https://swarm-gateways.net/bzz:/swarmapps.eth
Their source code can be found at: https://github.com/ethersphere/swarm-dapps
Thank you for considering to help out with the source code! We welcome contributions from anyone on the internet, and are grateful for even the smallest of fixes!
If you'd like to contribute to Swarm, please fork, fix, commit and send a pull request for the maintainers to review and merge into the main code base. If you wish to submit more complex changes though, please check up with the core devs first on our Swarm gitter channel to ensure those changes are in line with the general philosophy of the project and/or get some early feedback which can make both your efforts much lighter as well as our review and merge procedures quick and simple.
Please make sure your contributions adhere to our coding guidelines:
- Code must adhere to the official Go formatting guidelines (i.e. uses gofmt).
- Code must be documented adhering to the official Go commentary guidelines.
- Pull requests need to be based on and opened against the
- Code review guidelines.
- Commit messages should be prefixed with the package(s) they modify.
- E.g. "fuse: ignore default manifest entry"
The swarm library (i.e. all code outside of the
cmd directory) is licensed under the
GNU Lesser General Public License v3.0, also
included in our repository in the
The swarm binaries (i.e. all code inside of the
cmd directory) is licensed under the
GNU General Public License v3.0, also included
in our repository in the