Fail to start frontend if datanode is not started yet

[killme2008]

Start the frontend by cargo run -- frontend start, it fails with error:

2022-10-19T06:53:12.655693Z ERROR greptime: Fatal error occurs! err.msg=Failed to start frontend, source: Failed to connect Datanode at http://127.0.0.1:3001, source: Connect failed to http://127.0.0.1:3001, source: transport error err.code=InvalidArguments err.source=Failed to connect Datanode at http://127.0.0.1:3001, source: Connect failed to http://127.0.0.1:3001, source: transport error err.source.sources=[Connect failed to http://127.0.0.1:3001, source: transport error, transport error, error trying to connect: tcp connect error: Connection refused (os error 61), tcp connect error: Connection refused (os error 61), Connection refused (os error 61)] err.backtrace= 0 backtrace::backtrace::libunwind::trace::hcdfd8b20f85c976d
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.66/src/backtrace/libunwind.rs:93
   backtrace::backtrace::trace_unsynchronized::h92cf28ac583400a8
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.66/src/backtrace/mod.rs:66
 1 backtrace::backtrace::trace::h6b7004ab3cf91bc8
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.66/src/backtrace/mod.rs:53
 2 backtrace::capture::Backtrace::create::h3c74948d4e1cf141
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.66/src/capture.rs:176
 3 backtrace::capture::Backtrace::new::h7226af6750c0259f
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.66/src/capture.rs:140
 4 <snafu::backtrace_shim::Backtrace as snafu::GenerateImplicitData>::generate::h56a4c240894038fb
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/snafu-0.7.1/src/backtrace_shim.rs:15
   <client::error::ConnectFailedSnafu<__T0> as snafu::IntoError<client::error::Error>>::into_error::h07cffbdc2895730f
   /Users/dennis/programming/rust/greptimedb/src/client/src/error.rs:8
 5 <core::result::Result<T,E> as snafu::ResultExt<T,E>>::context::h3058afa5a0d39e9c
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/snafu-0.7.1/src/lib.rs:674
 6 client::client::Client::start::{{closure}}::h46a485a286c6b20d
   /Users/dennis/programming/rust/greptimedb/src/client/src/client.rs:18
 7 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h585b84001f933bc7
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
 8 client::database::Database::start::{{closure}}::hc1e0be2e20571fef
   /Users/dennis/programming/rust/greptimedb/src/client/src/database.rs:47
 9 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hb6691742c4ba1e24
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
10 frontend::instance::Instance::start::{{closure}}::hc032239d31f7e9e9
   /Users/dennis/programming/rust/greptimedb/src/frontend/src/instance.rs:49
11 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h275a4199379b94e5
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
12 frontend::frontend::Frontend::start::{{closure}}::h488858e4fbce1e98
   /Users/dennis/programming/rust/greptimedb/src/frontend/src/frontend.rs:65
13 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::he1b755ca15b90727
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
14 cmd::frontend::StartCommand::run::{{closure}}::h6379ae181be28c70
   /Users/dennis/programming/rust/greptimedb/src/cmd/src/frontend.rs:59
15 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h7e86ac04211df4b8
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
16 cmd::frontend::SubCommand::run::{{closure}}::h14c38beb8ebc3cf0
   /Users/dennis/programming/rust/greptimedb/src/cmd/src/frontend.rs:32
17 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hf5cd7ca36acebdc2
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
18 cmd::frontend::Command::run::{{closure}}::h37fc5c822209c937
   /Users/dennis/programming/rust/greptimedb/src/cmd/src/frontend.rs:20
19 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hbc1c7e9dfb681b08
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
20 greptime::SubCommand::run::{{closure}}::hfe34efcf57c821f6
   /Users/dennis/programming/rust/greptimedb/src/cmd/src/bin/greptime.rs:42
21 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::ha526081ffc686e05
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
22 greptime::Command::run::{{closure}}::hc3027e6bb054dfe3
   /Users/dennis/programming/rust/greptimedb/src/cmd/src/bin/greptime.rs:24
23 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h3e5c38c8b319c69e
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
24 greptime::main::{{closure}}::{{closure}}::h150227f052a748d4
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/macros/select.rs:507
25 <tokio::future::poll_fn::PollFn<F> as core::future::future::Future>::poll::h58ab895b1dc999f9
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/future/poll_fn.rs:38
26 greptime::main::{{closure}}::h131592af6dbe6a67
   /Users/dennis/programming/rust/greptimedb/src/cmd/src/bin/greptime.rs:71
27 <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::heca362505c43b233
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/future/mod.rs:91
28 tokio::park::thread::CachedParkThread::block_on::{{closure}}::haf5c2f7e3989929f
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/park/thread.rs:267
29 tokio::coop::with_budget::{{closure}}::h1f9c60441039674f
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/coop.rs:102
30 std::thread::local::LocalKey<T>::try_with::h9dd221d1bee65b98
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/thread/local.rs:445
31 std::thread::local::LocalKey<T>::with::h6ff59a675c53bfac
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/thread/local.rs:421
32 tokio::coop::with_budget::h8ae5fc82bb0ff555
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/coop.rs:95
   tokio::coop::budget::h07be502f023e7655
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/coop.rs:72
   tokio::park::thread::CachedParkThread::block_on::hee85c74ff6d8f673
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/park/thread.rs:267
33 tokio::runtime::enter::Enter::block_on::h56c42704226ce532
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/runtime/enter.rs:152
34 tokio::runtime::scheduler::multi_thread::MultiThread::block_on::ha98b099dcd7f847d
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/runtime/scheduler/multi_thread/mod.rs:79
35 tokio::runtime::Runtime::block_on::h25766516a8db7c6c
   /Users/dennis/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.21.1/src/runtime/mod.rs:492
36 greptime::main::h722aca8b4183f11b
   /Users/dennis/programming/rust/greptimedb/src/cmd/src/bin/greptime.rs:82
37 core::ops::function::FnOnce::call_once::h7129db01a69a9e6f
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/ops/function.rs:248
38 std::sys_common::backtrace::__rust_begin_short_backtrace::hc879d1a4845a6974
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/sys_common/backtrace.rs:122
39 std::rt::lang_start::{{closure}}::h1bee260c82f085d9
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/rt.rs:145
40 core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::hed516d662f36277a
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/core/src/ops/function.rs:280
   std::panicking::try::do_call::h91daf232e24a6a7e
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/panicking.rs:492
   std::panicking::try::h2c57c968d638ad44
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/panicking.rs:456
   std::panic::catch_unwind::h025a44fc3d544096
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/panic.rs:137
   std::rt::lang_start_internal::{{closure}}::h82476584b98e23f5
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/rt.rs:128
   std::panicking::try::do_call::h1fb3106e2c2e2c17
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/panicking.rs:492
   std::panicking::try::h41dca1e11e9d8387
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/panicking.rs:456
   std::panic::catch_unwind::h22e1c738a7065c7a
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/panic.rs:137
   std::rt::lang_start_internal::h2eada4ac4f4ee168
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/rt.rs:128
41 std::rt::lang_start::hdb5853e943c99a9a
   /rustc/87588a2afd9ca903366f0deaf84d805f34469384/library/std/src/rt.rs:144

We should not allow startup order dependencies between applications, it's not friendly for PaaS layer and users.

[zyy17]

@MichaelScofield Are you already working on this issue? If not, you can assign to me, should be very easy to me 😊

[MichaelScofield]

Close as resolved.